I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
plan on buying 220 machines when ever possible. While doing my research,
I've heard people mention single phase and three phase power but without the
benefits or limitations of each. Can anyone help me understand this a little
bit more or point me in a direction? -mike
>I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
>plan on buying 220 machines when ever possible. While doing my research,
>I've heard people mention single phase and three phase power but without the
>benefits or limitations of each. Can anyone help me understand this a little
>bit more or point me in a direction? -mike
>
>
Three phase is more economical to run, and the motors are cheaper. It also
allows you to instantly reverse the motor (without allowing it to coast to a
stop or to slow way down, as you do with a single phase motor).
But, three phase power is generally very expensive to bring into a residence.
Except for a few special metalworking machines where the instant reversing is a
plus - such as for some tapping and lathe operations - you would always choose
a single phase machine in a home or small shop.
If you get a used three phase machine, you can run it on single phase current
by using a phase converter or a VFD (variable frequency drive).
John Martin
I was about to say that. :)
dave
Scott Lurndal wrote:
> Bay Area Dave <[email protected]> writes:
>
>>Rico wrote
>>Bay Area Dave wrote:
>>
>>
>>>guess I didn't make myself clear, Doug. I live in San Jose, but had a
>>>business in Santa Clara. The VOLTAGE is 208 in Santa Clara, as opposed
>>>to 220 (or thereabouts) in San Jose. NOW do you understand what I was
>>>getting at? I thought you'd understand my business was in an industrial
>>>area since I had 3 phase power!!!
>>>
>>
>>that I don't know, since I was only concerned about the voltage in the
>>shop I leased
>>
>
>
> Santa Clara doesn't have _a_ voltage. Power is brought into Santa Clara
> via high-tension transmission lines where the voltage is somewhere around
> 115,000 volts (115kv). It hits a substation where it is transformed to
> lower voltages for distribution (22kv is common in south san jose, for
> instance, although newer systems use higher voltages). The 22kv is
> then distributed to home, commercial and industrial users. The 22kv will
> be transformed to 240v (nominal) single-phase for home users, and typically
> 480v three phase for commercial (office parks et. al.) and higher voltages for industrial
> users. Commercial and industrial users have on-site transformers to produce
> various voltages for various purposes - 240/277/208 volt systems are quite
> common in commerical and industrial facilities - 277v is very efficient for
> flourescent lights while 240/208 is used for industrial purposes. 240 can be
> centertapped to ground to provide the common 120 (as is done by the grounded
> conductor at your home service entrance, for example). In all cases, the
> 22kv distribution will be three phase and where the commercial or industrial
> entity has its own transformer, the three phase will be distributed to the
> business. To save wiring costs, three phase isn't distributed typically
> within residential neighborhoods (past the 22kv stepdown transformer).
>
> scott
Hope your shop is in commercial space and not your home.
John
Mike B wrote:
>I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
>plan on buying 220 machines when ever possible. While doing my research,
>I've heard people mention single phase and three phase power but without the
>benefits or limitations of each. Can anyone help me understand this a little
>bit more or point me in a direction? -mike
>
>
>
>
Mike, discussions of 3-phase may well be moot if you're in the US. It's
what industrial users of 5+ HP motors use, and not normally available to
residential customers. This is probably a good thing to examine
http://www.woodweb.com/knowledge_base/When_is_threephase_power.html
It's like having current at 180Hz providing a more constant push, though at
the same potential (power) as single. You can get a converter to generate a
close clone to 3-phase, but it's going to use enough power to negate any
gain you might make. For lathes and such, varying the phase angle in the
converter is used to control speed without a significant loss of torque
above a minimum speed.
BTW, capacitor starters generate pulses to get a single-phase motor running,
then cut out. Capacitor run motors use an interboost from the run capacitor
to get greater output from a smaller motor.
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
> plan on buying 220 machines when ever possible. While doing my research,
> I've heard people mention single phase and three phase power but without
the
> benefits or limitations of each. Can anyone help me understand this a
little
> bit more or point me in a direction? -mike
>
>
"Jon" <[email protected]> writes:
>220 is single phase. Your wise in utilizing it. Upgrading to 3-phase power
>would require a whole new "service entrance", main panel, and perhaps "line
>work" to replace the line transformer feeding your location.
>Heck, you might not even have it available at the pole in your location.
I'm pretty sure the power poles running along the front of my lot are
three phase. I really doubt the power company would install a transformer
and the underground feed to my shop that would provide me with three phase
power, even if it is there. If they did do it, they would probably charge
an arm and a leg.
I actually called one time to inquire about three phase and just got
shuffled from department to department and gave up at the time.
The power for my house actually comes from poles run down the center of my
two lots. There was an alley easement, but it was vacated many years ago.
The power company has to drive on customer driveways and across customer
yards to access their poles and wires.
Brian Elfert
Count the wires up to your pole.
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> Is there anyway to determine what I have short of having an electrician
come
> out? Thanks for the responses. -mike
"Jon" <[email protected]> writes:
>> I actually called one time to inquire about three phase and just got
>> shuffled from department to department and gave up at the time.
>If you called your local power co. I can believe that. You'd have gotten
>some real answers from a contractor. You know.. in regards to quoting a
>possible job.
A contractor has nothing to do with getting power to a meter socket. I
could have a contractor put in a meter scoket and service, and then have
the contractor call for a hookup and find it won't happen or only for big
bucks.
I bet most residential electricians have never wired a house for three
phase and have no idea if the power company would even do it.
Brian Elfert
On Fri, 24 Oct 2003 14:38:49 GMT, "Mike B" <[email protected]> wrote:
>I've heard people mention single phase and three phase power but without the
>benefits or limitations of each.
Best explanation I've seen is on the Old Woodworking Machines site
http://www.oldwwmachines.com/FAQ/
3 phase, what it does, how to convert one to the other.
(Even if the bunch of tightasses don't think _my_ saw is good enough!)
If you've got it, or can get it cheaply, three phase every time.
--
Die Gotterspammerung - Junkmail of the Gods
Three phase power is more efficient. Typically 3 phase power is only
available in commercial and industrial locations. One doesn't usually find
it in a residence. Three phase motors require a magnetic motor starter with
short circuit and overload protection.
Ms Leslie
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
> plan on buying 220 machines when ever possible. While doing my research,
> I've heard people mention single phase and three phase power but without
the
> benefits or limitations of each. Can anyone help me understand this a
little
> bit more or point me in a direction? -mike
>
>
>
>Three phase power is more efficient. Typically 3 phase power is only
>available in commercial and industrial locations. One doesn't usually find
>it in a residence. Three phase motors require a magnetic motor starter with
>short circuit and overload protection.
>
>Ms Leslie
>
Correct on everything but the starter. Overload protection is a good idea for
any motor, but you don't need it for either single phase or three phase.
John Martin
>Correct on everything but the starter. Overload protection is a good idea
>for
>any motor, but you don't need it for either single phase or three phase.
>
>
Did they just repeal part III of article 430 and not tell me. I hate it when
that happens. ;-)
It's true that a high percentage of motors, particularly those sold retail,
have internal overload protection (check the labels on the motor) but it still
needs to be there somewhere. The branch circuit breaker is sized to the
starting current, not the full load current and can typically be 250% of what
the motor will safely run at. (see table 430-52) That can also be more than
twice the regular ampacity of the wire feeding the motor. (stuff like 40a
breakers on 14ga wire<legal>). It is the overload protection that keeps this
safe.
>
>>Correct on everything but the starter. Overload protection is a good idea
>>for
>>any motor, but you don't need it for either single phase or three phase.
>>
>>
>
>Did they just repeal part III of article 430 and not tell me. I hate it when
>that happens. ;-)
>It's true that a high percentage of motors, particularly those sold retail,
>have internal overload protection (check the labels on the motor) but it
>still
>needs to be there somewhere. The branch circuit breaker is sized to the
>starting current, not the full load current and can typically be 250% of what
>the motor will safely run at. (see table 430-52) That can also be more than
>twice the regular ampacity of the wire feeding the motor. (stuff like 40a
>breakers on 14ga wire<legal>). It is the overload protection that keeps this
>safe.
>
>
Greg:
I'm not an electrician, and don't have easy access to the National Electrical
Code. Are you really telling me that the Code requires overload protection for
every motor? Because if you are, I guess I've seen an awful lot of machines
that don't appear to meet that requirement.
I just took a look at all of the motors in my shop. All of those, at least,
that I could read the labels on without pulling them off the machine or
resorting to a mirror.
three phase
horizontal mill, static converter
single phase 220V
table saw
thickness planer
dust collector
single phase 110V
drill press
metal shaper
wood shaper
wood/metal band saw
wood lathe
metal lathe
None of the motor labels that I could see said anything about overload
protection. The only machine that I know has it is the table saw, but that is
a manual starter with heater coils. Am I missing something on the labels? I
do remember a few motors with reset buttons, but not of these have them.
I have on a few occasions run the bandsaw hard enough to kick the overload. 1
HP Baldor motor, 12 amps at 110V. It kicks the 20 amp breaker, though, not
anything in the motor.
John Martin
>
>>Am I missing something on the labels?
>
>It may say "thermally protected" or something similar or there could be a pop
>out button on the tool itself.
>There are some exceptions to the rule for small, cord and plug connected,
>fractional HP motors but most motors will have some kind of overload
>protection.
>
>
Greg:
The Delco motor on my metal lathe does say "Thermotron" on the label, but other
than the "40 degree" rise rating on most of the motors, there is nothing
referring to any overload or thermal protection on any of the others. No pop
out buttons, either. These range from a big old GE motor probably from the
1920s to a Baldor from the mid-1980s. Oh, and in my earlier email I forgot the
110V scroll saw and jointer.
On those of the motors that I've had apart for cleaning or new bearings, the
only obvious switches that I recall seeing were the centrifugal starting
switches.
If I'm reading you right, you are saying that:
1. Most of these motors do incorporate internal overload protection, even
though they don't mention it.
2. The electrical code requires that these machines be equipped with overload
protection in addition to the circuit breaker.
Looking at a circa 1985 McMaster Carr catalog. Capacitor start single phase
motors. Copy states "Enclosed motors with rubber mount feature automatic
thermal protection - not for use where unexpected restarting might be a
hazard". That copy, though, leads me to believe that the motors offered which
were not enclosed, or were not rubber mounted, had no thermal protection. And
only a few of those offered were enclosed and rubber mounted.
Not trying to be a PITA, I'd just like to know. Thanks.
John Martin
You have me curious now. As I said there is an exception for small motors used
intermittantly, basically like drill motors and such but even those Chinese $15
box fans have a thermal fuse.
I haven't really looked at my tools but I know my Makita side grinder, Sears
table saw and drill press have protection.
In the case of the fractional HP induction motors like my drill press uses the
thermal is in the windings. That is a cradle mount motor like you were talking
about tho.
he table saw has a pop out in the frame of the saw, The Makita has a button on
the end.
Article 430 can usually get a fist fight started at an inspector meeting so I
am not surprised that there can be confusion with cord and plug consumer
products.
If something get's a U/L listing we are pretty much stuck with it, whether it
meets the letter of the NEC or not.
>Looking at a circa 1985 McMaster Carr catalog. Capacitor start single phase
>motors. Copy states "Enclosed motors with rubber mount feature automatic
>thermal protection - not for use where unexpected restarting might be a
>hazard". That copy, though, leads me to believe that the motors offered
>which
>were not enclosed, or were not rubber mounted, had no thermal protection.
>And
>only a few of those offered were enclosed and rubber mounted.
>
>Not trying to be a PITA, I'd just like to know. Thanks.
>
>John Martin
WARNING!!!
OT, long boring code dissertation
OK I did some looking.
The first thing you need to define is "Continuous duty motor"
***NEC2002
430.22(E)
Note: Any motor application shall be considered as continuous duty unless the
nature of the apparatus it drives is such that the motor will not operate
continuously with load under any condition of use.
***
***NEC2002
430.32 Continuous-Duty Motors.
(A) More Than 1 Horsepower. Each continuous-duty motor rated more than 1 hp
shall be protected against overload by one of the means in 430.32(A)(1) through
(A)(4).
OK that's a slam dunk
Now how about a non-continuous duty motor
***NEC2002
430.33 Intermittent and Similar Duty.
A motor used for a condition of service that is inherently short-time,
intermittent, periodic, or varying duty, as illustrated by Table 430.22(E),
shall be permitted to be protected against overload by the branch-circuit
short-circuit and ground-fault protective device, provided the protective
device rating or setting does not exceed that specified in Table 430.52.
Any motor application shall be considered to be for continuous duty unless the
nature of the apparatus it drives is such that the motor cannot operate
continuously with load under any condition of use.
If a motor is selected for duty-cycle service (short-time, intermittent,
periodic, or varying), it can be assumed that the motor will not operate
continuously, due to the nature of the apparatus or machinery it drives.
Therefore, prolonged overloads are rare unless mechanical failure in the driven
apparatus stalls the motor; in this case, however, the branch-circuit
protective device would open the circuit. The omission of overload protective
devices for such motors is based on the type of duty and not on the time rating
of the motor.
***
IF the branch circuit O/C device <fuse/breaker> is sized properly for the motor
and the motor can't be locked on (I.E.trigger control with no "lock on" button)
you can do without overload protection. Bear in mind this limits the size of
the motor you can use. If it's too small the typical 15/20a branch circuit O/C
device will not adequately protect the motor. That's why we see thermal fuses
in those cheap fans. This was written, assuming you would size the branch
circuit to a particular motor.
If you have more than one motor on a branch circuit they must have overload
protection.
***NEC2002
430.53 Several Motors or Loads on One Branch Circuit.
Two or more motors or one or more motors and other loads shall be permitted to
be connected to the same branch circuit under conditions specified in 430.53(D)
and in 430.53(A), (B), or (C).
(A) Not Over 1 Horsepower. Several motors, each not exceeding 1 hp in rating,
shall be permitted on a nominal 120-volt branch circuit protected at not over
20 amperes or a branch circuit of 600 volts, nominal, or less, protected at not
over 15 amperes, if all of the following conditions are met:
(1) The full-load rating of each motor does not exceed 6 amperes.
(2) The rating of the branch-circuit short-circuit and ground-fault
protective device marked on any of the controllers is not exceeded.
(3) Individual overload protection conforms to 430.32.
Two or more motors or one or more motors and other loads may be connected to
the same 120-volt, 15- or 20-ampere, single-phase lighting circuit as long as
each motor is rated not more than 1 hp, the full-load rating of each motor does
not exceed 6 amperes, and the rating of the branch-circuit protective device is
not exceeded.
The requirements for overload protection, as provided in 430.32, must be
applied in all cases, regardless of the number (one or more) of motors or the
type of branch circuit.
***
This brings is to something more relevant to what we use.
***NEC2002
430.42 Motors on General-Purpose Branch Circuits.
Overload protection for motors used on general-purpose branch circuits as
permitted in Article 210 shall be provided as specified in 430.42(A), (B), (C),
or (D).
(A) Not Over 1 Horsepower. One or more motors without individual overload
protection shall be permitted to be connected to a general-purpose branch
circuit only where the installation complies with the limiting conditions
specified in 430.32(B) and (D) and 430.53(A)(1) and (A)(2).
(B) Over 1 Horsepower. Motors of ratings larger than specified in 430.53(A)
shall be permitted to be connected to general-purpose branch circuits only
where each motor is protected by overload protection selected to protect the
motor as specified in 430.32. Both the controller and the motor overload device
shall be approved for group installation with the short-circuit and
ground-fault protective device selected in accordance with 430.53
(C) Cord-and-Plug Connected. Where a motor is connected to a branch circuit by
means of an attachment plug and receptacle and individual overload protection
is omitted as provided in 430.42(A), the rating of the attachment plug and
receptacle shall not exceed 15 amperes at 125 volts or 250 volts. Where
individual overload protection is required as provided in 430.42(B) for a motor
or motor-operated appliance that is attached to the branch circuit through an
attachment plug and receptacle, the overload device shall be an integral part
of the motor or of the appliance. The rating of the attachment plug and
receptacle shall determine the rating of the circuit to which the motor may be
connected, as provided in Article 210.
***
You see why someone could get confused??
Basically I wouldn't want anything that didn't have some kind of overload
protection unless it was a throw away tool or something you only run
intermittantly with a trigger. Certainly any kind of a free standing tool like
a planer, jointer or table saw that has an on/off switch requires O/L
protection because it is capable of "continuous duty".
IMHO ... and that is how the fist fights begin at the inspector meetings ;-)
you aren't likely to have 3 phase power unless you are in an industrial
zoned area. your home would be single phase.
dave
Mike B wrote:
> I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
> plan on buying 220 machines when ever possible. While doing my research,
> I've heard people mention single phase and three phase power but without the
> benefits or limitations of each. Can anyone help me understand this a little
> bit more or point me in a direction? -mike
>
>
All of Santa Clara, or just industrial areas?
208v/120v is common in an industrial area.
http://www.dataforth.com/catalog/pdf/an110.pdf
Bay Area Dave wrote:
> guess I didn't make myself clear, Doug. I live in San Jose, but had a
> business in Santa Clara. The VOLTAGE is 208 in Santa Clara, as opposed
> to 220 (or thereabouts) in San Jose. NOW do you understand what I was
> getting at? I thought you'd understand my business was in an industrial
> area since I had 3 phase power!!!
>
> dave
>
> Doug Miller wrote:
> > In article <[email protected]>, Bay Area Dave <[email protected]> wrote:
> >
> >>If he lives in Santa Clara, CA, the power is only 208. I used to have a
> >>business there, so I went with a 208V 3 phase 5HP motor on my compressor.
> >>
> >
> > Dave, the key word there is "business". It's *very* rare in the US to have
> > 3-phase power in a residence.
> >
> > --
> > Regards,
> > Doug Miller (alphageek-at-milmac-dot-com)
>
>
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
Unless you already have 3 phase feeding your shop and pay for it, I think
you will find that the power company will charge a premium to supply it to
you. It requires more equipment on their part to supply it to you and they
in return expect higher useage to justify it. Check with your utility
company to see what your costs to get 3 phase would be, before you even
entertain which is better for a saw.
Bob
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
> plan on buying 220 machines when ever possible. While doing my research,
> I've heard people mention single phase and three phase power but without
the
> benefits or limitations of each. Can anyone help me understand this a
little
> bit more or point me in a direction? -mike
>
>
If he lives in Santa Clara, CA, the power is only 208. I used to have a
business there, so I went with a 208V 3 phase 5HP motor on my compressor.
Wade Lippman wrote:
> "Mike B" <[email protected]> wrote in message
> news:[email protected]...
>
>>Is there anyway to determine what I have short of having an electrician
>
> come
>
>>out? Thanks for the responses. -mike
>>
>
>
> Yes, real easy. 220 (actually 240v) is single phase. It would be real
> strange for a residence to have three phase.
> So, you have single phase.
>
> Your question should be whether to use 240v or 120v.
>
> If you have 240v in your shop, then you should use it. It simply works
> better; do a search and see what people say about it.
> If you don't have 240v, then 120v should be okay also.
>
>
Good stuff. Thanks for the input everyone! -mike
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
> plan on buying 220 machines when ever possible. While doing my research,
> I've heard people mention single phase and three phase power but without
the
> benefits or limitations of each. Can anyone help me understand this a
little
> bit more or point me in a direction? -mike
>
>
In article <[email protected]>, Bay Area Dave <[email protected]> wrote:
>If he lives in Santa Clara, CA, the power is only 208. I used to have a
>business there, so I went with a 208V 3 phase 5HP motor on my compressor.
>
Dave, the key word there is "business". It's *very* rare in the US to have
3-phase power in a residence.
--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)
On Fri, 24 Oct 2003 15:58:47 GMT, [email protected] (Doug Miller)
wrote:
>It's *very* rare in the US to have
>3-phase power in a residence.
I thought some of you guys had (domestic) heating that ran off it ?
Here in the UK it depends how your power is delivered. If it's
underground (nearly everyone) then it's a serious spend to get 3
phase. If it's an overhead feed (just the rustics) then it's a lot
cheaper as there's normally line-of-sight to a suitable transformer.
--
Die Gotterspammerung - Junkmail of the Gods
>I thought some of you guys had (domestic) heating that ran off it ?
>
>Here in the UK it depends how your power is delivered. If it's
>underground (nearly everyone) then it's a serious spend to get 3
>phase. If it's an overhead feed (just the rustics) then it's a lot
>cheaper as there's normally line-of-sight to a suitable transformer.
We use single phase 120/240 with the 240 feeding large loads. It is derived
from a single phase center tapped transformer. In fact you don't see 3 phase
transformers until you get to very large industrial pad mounted units.
The norm here (US) is a smaller single phase transformer hanging on the pole
and serving 2-3 homes. If the 3 phases are available on the pole, usually only
if you live on a main power route, it is possible to add one more transformer
and provide "open vee" 3p delta with a centertap. That uses the existing
service and adds the extra transformer to get the 3d phase. That arrangement
isn't perfect 3 phase and can get some strange phase shifts with unbalanced
loads between phase ab and bc but it does work, particularly if you are just
feeding motor loads that balance out fairly well.
For a bit more money they will add the 3d transformer and give you true 240v
delta or, more common 208v wye with 3 120v to ground legs.
On 25 Oct 2003 01:47:48 GMT, [email protected] (Gfretwell) wrote:
>For a bit more money they will add the 3d transformer and give you true 240v
>delta or, more common 208v wye with 3 120v to ground legs.
American electrics terrify me (a lot of your working practices are
seen as screaming nightmares in our standards documents). And you do
it in timber framed buildings too !
But I really don't understand how you can operate a system with such a
mixture of 240 / 208 and 110 / 120 V systems. It must keep the
motor-swap shops in business.
Here in Europe we just have single phase and three phase. Then barring
the half-a-dozen different socket outlet styles, I can move any
appliance around between _any_ two European countries and have it
work, straight off. Standard voltage, right across the continent.
Even dodgy old places like Spain and Greece are now getting their acts
together (15 years ago I installed VFDs in a Spanish factory where we
barely had a working phoneline)
--
Die Gotterspammerung - Junkmail of the Gods
>American electrics terrify me (a lot of your working practices are
>seen as screaming nightmares in our standards documents)
It is what happens when you invent something and never abandon any idea each
inventor came up with.
You folks were helped a lot by a war that destroyed enough of your
infrastructure that you had to build it all back at one time, with uniform
standards. We still have major utilities that date back to Thomas Edison.
I have always said, the best thing we could have done was bomb all of our
infrastructure to the ground in 1945 and build new stuff so we would be on
equal footing with the rest of the world. In the long run we would have saved
money.
>But I really don't understand how you can operate a system with such a
>mixture of 240 / 208 and 110 / 120 V systems. It must keep the
>motor-swap shops in business.
Most commercial grade motors can be tapped for any of those voltages by
swapping a couple wires in the bell.
Gfretwell wrote:
> infrastructure to the ground in 1945 and build new stuff so we would be on
> equal footing with the rest of the world. In the long run we would have
> saved money.
Don't give Al Qaeda any ideas...
--
Michael McIntyre ---- Silvan <[email protected]>
Linux fanatic, and certified Geek; registered Linux user #243621
http://www.geocities.com/Paris/Rue/5407/
"Andy Dingley" <[email protected]> wrote in message
news:[email protected]...
> On 25 Oct 2003 01:47:48 GMT, [email protected] (Gfretwell) wrote:
>
> >For a bit more money they will add the 3d transformer and give you true
240v
> >delta or, more common 208v wye with 3 120v to ground legs.
>
> American electrics terrify me (a lot of your working practices are
> seen as screaming nightmares in our standards documents). And you do
> it in timber framed buildings too !
>
> But I really don't understand how you can operate a system with such a
> mixture of 240 / 208 and 110 / 120 V systems. It must keep the
> motor-swap shops in business.
It is not a hard concept. You only make a mistake once! <g>
Really, the 110 plug will not fit in the 220, and also the other way around.
If you don't understand it, don't play with it. A few do get it wrong, but
not many.
It is nice to run 220 a greater distance, with lighter wires, and less
voltage loss. You can't claim that as a disadvantage for us.
--
Jim in NC
In article <[email protected]>,
Greg O <[email protected]> wrote:
>
>
>
>"Al Reid" <[email protected]> wrote in message
>news:[email protected]...
>> Look at the main breaker in your distribution panel. If it has two
>handles tied together then you gave 220v single phase. If there
>> are three , then you have 3 phase. If it is a residential installation, I
>doubt you have 3-phase power.
>>
>> --
>>
>
>Might not help. Some main breakers are a one molded-one piece affair. Not
>easy to tell the difference by just looking at it. On the other hand there
>should be some printing on the breaker that will tell the difference.
>Greg
The easy way is to _count_the_wires_ tied to the master breaker. this
works *regardless* of whether it's a "molded one-piece affair", or not.
<grin>
that I don't know, since I was only concerned about the voltage in the
shop I leased
dave
Rico wrote:
> All of Santa Clara, or just industrial areas?
>
> 208v/120v is common in an industrial area.
>
> http://www.dataforth.com/catalog/pdf/an110.pdf
>
>
> Bay Area Dave wrote:
>
>>guess I didn't make myself clear, Doug. I live in San Jose, but had a
>>business in Santa Clara. The VOLTAGE is 208 in Santa Clara, as opposed
>>to 220 (or thereabouts) in San Jose. NOW do you understand what I was
>>getting at? I thought you'd understand my business was in an industrial
>>area since I had 3 phase power!!!
>>
>>dave
>>
>>Doug Miller wrote:
>>
>>>In article <[email protected]>, Bay Area Dave <[email protected]> wrote:
>>>
>>>
>>>>If he lives in Santa Clara, CA, the power is only 208. I used to have a
>>>>business there, so I went with a 208V 3 phase 5HP motor on my compressor.
>>>>
>>>
>>>Dave, the key word there is "business". It's *very* rare in the US to have
>>>3-phase power in a residence.
>>>
>>>--
>>>Regards,
>>> Doug Miller (alphageek-at-milmac-dot-com)
>>
>>
>
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> -----== Over 100,000 Newsgroups - 19 Different Servers! =-----
Is there anyway to determine what I have short of having an electrician come
out? Thanks for the responses. -mike
"Erik Ahrens" <erikl_nospam_@_nospam_syserco.com> wrote in message
news:[email protected]...
> I can think of two benefits of 3-phase -
> More HP in a smaller frame motor.
> Reduced electrical cost both in demand and KW.
>
> Keep in mind that having 220 in your shop doesn't mean you have 3-phase
> available.
>
> Erik
>
>
> "Mike B" <[email protected]> wrote in message
> news:[email protected]...
> > I'm looking to purchase a cabinet saw. I have 220 in my shop currently
and
> > plan on buying 220 machines when ever possible. While doing my research,
> > I've heard people mention single phase and three phase power but without
> the
> > benefits or limitations of each. Can anyone help me understand this a
> little
> > bit more or point me in a direction? -mike
> >
> >
>
>
"Bay Area Dave" <[email protected]> wrote in message
news:[email protected]...
> guess I didn't make myself clear, Doug. I live in San Jose, but had a
> business in Santa Clara. The VOLTAGE is 208 in Santa Clara, as opposed
> to 220 (or thereabouts) in San Jose. NOW do you understand what I was
> getting at? I thought you'd understand my business was in an industrial
> area since I had 3 phase power!!!
>
>
An office I used to work in had 2 phases of 3 phase supplied to them, so
they had 208v.
It still isn't 3 phase, since they did not get the 3rd phase.
A factory I worked at had real 3 phase, so they used mainly 208v motors,
though some of the big ones were true 3 phase.
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> Is there anyway to determine what I have short of having an electrician
come
> out? Thanks for the responses. -mike
>
Yes, real easy. 220 (actually 240v) is single phase. It would be real
strange for a residence to have three phase.
So, you have single phase.
Your question should be whether to use 240v or 120v.
If you have 240v in your shop, then you should use it. It simply works
better; do a search and see what people say about it.
If you don't have 240v, then 120v should be okay also.
"Mike D2" <[email protected]> wrote:
> look at the number of lines coming from your transformer into your shop. 3
> lines = 3 phase, 2 lines = 1 phase.
Maybe. I've got 3 wires coming to my house. It's 240V single phase.
There's two hot legs plus a neutral. On the overhead drop from the pole
on the street, the neutral is bare, but once it goes into a conduit down
the side of the house to the meter and panel box, all three are
insulated.
This is dangerous stuff to be guessing about. If you're not sure, the
best thing to do is call an electrician. He'll be able to tell you what
you've got in about 30 seconds by looking at it. Might cost you a few
bucks for his time, but it beats burning your house down.
Bay Area Dave <[email protected]> writes:
>Rico wrote
> Bay Area Dave wrote:
>
>>guess I didn't make myself clear, Doug. I live in San Jose, but had a
>>business in Santa Clara. The VOLTAGE is 208 in Santa Clara, as opposed
>>to 220 (or thereabouts) in San Jose. NOW do you understand what I was
>>getting at? I thought you'd understand my business was in an industrial
>>area since I had 3 phase power!!!
>>
>that I don't know, since I was only concerned about the voltage in the
>shop I leased
>
Santa Clara doesn't have _a_ voltage. Power is brought into Santa Clara
via high-tension transmission lines where the voltage is somewhere around
115,000 volts (115kv). It hits a substation where it is transformed to
lower voltages for distribution (22kv is common in south san jose, for
instance, although newer systems use higher voltages). The 22kv is
then distributed to home, commercial and industrial users. The 22kv will
be transformed to 240v (nominal) single-phase for home users, and typically
480v three phase for commercial (office parks et. al.) and higher voltages for industrial
users. Commercial and industrial users have on-site transformers to produce
various voltages for various purposes - 240/277/208 volt systems are quite
common in commerical and industrial facilities - 277v is very efficient for
flourescent lights while 240/208 is used for industrial purposes. 240 can be
centertapped to ground to provide the common 120 (as is done by the grounded
conductor at your home service entrance, for example). In all cases, the
22kv distribution will be three phase and where the commercial or industrial
entity has its own transformer, the three phase will be distributed to the
business. To save wiring costs, three phase isn't distributed typically
within residential neighborhoods (past the 22kv stepdown transformer).
scott
look at the number of lines coming from your transformer into your shop. 3
lines = 3 phase, 2 lines = 1 phase.
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> Is there anyway to determine what I have short of having an electrician
come
> out? Thanks for the responses. -mike
>
> "Erik Ahrens" <erikl_nospam_@_nospam_syserco.com> wrote in message
> news:[email protected]...
> > I can think of two benefits of 3-phase -
> > More HP in a smaller frame motor.
> > Reduced electrical cost both in demand and KW.
> >
> > Keep in mind that having 220 in your shop doesn't mean you have 3-phase
> > available.
> >
> > Erik
> >
> >
> > "Mike B" <[email protected]> wrote in message
> > news:[email protected]...
> > > I'm looking to purchase a cabinet saw. I have 220 in my shop currently
> and
> > > plan on buying 220 machines when ever possible. While doing my
research,
> > > I've heard people mention single phase and three phase power but
without
> > the
> > > benefits or limitations of each. Can anyone help me understand this a
> > little
> > > bit more or point me in a direction? -mike
> > >
> > >
> >
> >
>
>
On Fri, 24 Oct 2003 14:15:46 -0500, Lazarus Long
<[email protected]> wrote:
>the neutral at my address is uninsulated. So it isn't always
>insulated.
Stop it ! You're scaring the Europeans 8-)
In article <[email protected]>, Andy Dingley
<[email protected]> wrote:
> On-site, we use 240V -> 110V isolation transformers, centre-tapped and
> earthed. So there's never any more than 55V earth difference on either
> leg, thus the tool is safe for on-site work.
That system makes sense. In household mains, is it a two-wire system,
with the normal potential 240V to earth (ground)?
Do you have a safety (fault) ground (earth)?
Kevin
On Fri, 24 Oct 2003 11:42:39 -0700, Rico <[email protected]> wrote:
>
>Neutral is typically (always?) insulated in a single phase
>system. Single phase = 3 insulated wires plus uninsulated
>ground.
>
>Rico
>
the neutral at my address is uninsulated. So it isn't always
insulated.
Rico <[email protected]> writes:
>Gfretwell wrote:
>> >look at the number of lines coming from your transformer into your shop. 3
>> >lines = 3 phase, 2 lines = 1 phase.
>> >
>>
>> The number of INSULATED lins ...
>> There is also a neutral that is typically uninsulated.
>> Total is 4 wires for 3p, 3 wires for 1p (in the US).
>>
>
>Neutral is typically (always?) insulated in a single phase
>system. Single phase = 3 insulated wires plus uninsulated
>ground.
While the grounded (aka neutral) conductor in premises
wiring is indeed typically insulated, the original poster was
refering to the service drop, where in most cases the
grounded conductor (neutral) is uninsulated.
scott
Gfretwell wrote:
> >look at the number of lines coming from your transformer into your shop. 3
> >lines = 3 phase, 2 lines = 1 phase.
> >
>
> The number of INSULATED lins ...
> There is also a neutral that is typically uninsulated.
> Total is 4 wires for 3p, 3 wires for 1p (in the US).
>
Neutral is typically (always?) insulated in a single phase
system. Single phase = 3 insulated wires plus uninsulated
ground.
Rico
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
Rico wrote...
> > The number of INSULATED lins ...
> > There is also a neutral that is typically uninsulated.
> > Total is 4 wires for 3p, 3 wires for 1p (in the US).
> >
>
> Neutral is typically (always?) insulated in a single phase
> system. Single phase = 3 insulated wires plus uninsulated
> ground.
Careful! Let's not get neutral and ground wires confused.
Jim
"Blair" <[email protected]> writes:
>"Scott Lurndal" <[email protected]> wrote in message
>news:[email protected]...
>> Rico <[email protected]> writes:
>> >Gfretwell wrote:
>> >> >look at the number of lines coming from your transformer into your
>shop. 3
>> >> >lines = 3 phase, 2 lines = 1 phase.
>> >> >
>> >>
>> >> The number of INSULATED lins ...
>> >> There is also a neutral that is typically uninsulated.
>> >> Total is 4 wires for 3p, 3 wires for 1p (in the US).
>> >>
>> >
>> >Neutral is typically (always?) insulated in a single phase
>> >system. Single phase = 3 insulated wires plus uninsulated
>> >ground.
>>
>> While the grounded (aka neutral) conductor in premises
>> wiring is indeed typically insulated, the original poster was
>> refering to the service drop, where in most cases the
>> grounded conductor (neutral) is uninsulated.
>>
>> scott
>>
>Are you referring to neutral supported cable as it comes overhead to your
>home?
>
Premises Wiring == Within the premises.
Service Drop == From the utility company to the service entrance
Service Entrance == Meter base and premises disconnect.
Are you referring to neutral supported cable as it comes overhead to your
home?
"Scott Lurndal" <[email protected]> wrote in message
news:[email protected]...
> Rico <[email protected]> writes:
> >Gfretwell wrote:
> >> >look at the number of lines coming from your transformer into your
shop. 3
> >> >lines = 3 phase, 2 lines = 1 phase.
> >> >
> >>
> >> The number of INSULATED lins ...
> >> There is also a neutral that is typically uninsulated.
> >> Total is 4 wires for 3p, 3 wires for 1p (in the US).
> >>
> >
> >Neutral is typically (always?) insulated in a single phase
> >system. Single phase = 3 insulated wires plus uninsulated
> >ground.
>
> While the grounded (aka neutral) conductor in premises
> wiring is indeed typically insulated, the original poster was
> refering to the service drop, where in most cases the
> grounded conductor (neutral) is uninsulated.
>
> scott
>
On Fri, 24 Oct 2003 23:06:16 +0100, Andy Dingley
<[email protected]> wrote:
>On Fri, 24 Oct 2003 14:15:46 -0500, Lazarus Long
><[email protected]> wrote:
>
>>the neutral at my address is uninsulated. So it isn't always
>>insulated.
>
>Stop it ! You're scaring the Europeans 8-)
What? This isn't common? It's that way on all the houses I can see
around here. Nobody's place is going up in flames, at least not
because of anything the power companies doing.
How's it done in Europe?
On Fri, 24 Oct 2003 22:59:04 -0500, Lazarus Long
<[email protected]> wrote:
>How's it done in Europe?
We do bind our earths (grounds) to our neutrals, but we only do it at
our substations, not at each premises (actually there are earthing
systems where this is done, but it's not the usual way). So it's
accepted that neutral may well be at some considerable potential w.r.
to earth (depending on soil conditions) and thus should be insulated.
We generally regard electricity supply as a "3 wire" deal, where the
electricity company feed offers live, neutral and earth as a package,
and they're all treated separately inside the premises.
--
Die Gotterspammerung - Junkmail of the Gods
On Sat, 25 Oct 2003 12:06:26 +0100, Andy Dingley
<[email protected]> brought forth from the murky depths:
>On Fri, 24 Oct 2003 22:59:04 -0500, Lazarus Long
><[email protected]> wrote:
>
>>How's it done in Europe?
>
>We do bind our earths (grounds) to our neutrals, but we only do it at
>our substations, not at each premises (actually there are earthing
>systems where this is done, but it's not the usual way). So it's
>accepted that neutral may well be at some considerable potential w.r.
>to earth (depending on soil conditions) and thus should be insulated.
Crikey, it sounds like yet another Lucas scheme to badly
ground the world. I'll bet you can see 50v floating grounds
in that system.
>We generally regard electricity supply as a "3 wire" deal, where the
>electricity company feed offers live, neutral and earth as a package,
>and they're all treated separately inside the premises.
So measuring each wire to earth, you get 220v on the live
and zero on the neutral? Here, we measure 120v from each
of the lives to ground, and 240v across them.
Here, we have two lives and a ground. Neutrals appear in
the house as feedbacks to ground. The two lives are carried
through the house singularly as 120v lives and the neutrals
run back to the service panel (you might call that the mains
box or something similar) and are tied to the same bar as
ground. Grounding rods are at the telephone poles (old style)
and at each house (newer).
=====================================================================
-=Everything in Moderation,=- NoteSHADES(tm) glare guards
-=including moderation.=- http://www.diversify.com
=====================================================================
On Sat, 25 Oct 2003 16:32:43 GMT, Larry Jaques <jake@di\/ersify.com>
wrote:
>Here, we have two lives and a ground.
We have a similar system to that for on-site work.
50V is "safe". It must be safe, because that's what the telephone
system runs on, which is owned by the post office, so it would cost
The Man a bunch of money to insulate. So 50V is regarded as the
borderline between "compleely safe" and "instantly lethal".
On-site, we use 240V -> 110V isolation transformers, centre-tapped and
earthed. So there's never any more than 55V earth difference on either
leg, thus the tool is safe for on-site work.
--
Die Gotterspammerung - Junkmail of the Gods
On Sun, 26 Oct 2003 01:11:20 GMT, Kevin Craig <[email protected]>
wrote:
>In household mains, is it a two-wire system,
>with the normal potential 240V to earth (ground)?
Cable is three core; live (red), neutral (black), earth, where earth
is a bare wire inside the overall jacket.
We have two systems of wiring.
Radials are wired with a low-value fuse or breaker at the panel,
appropriate to what's connected to the circuit and the cable it's
wired in. Most of Europe uses this system.
The UK has fused plugs throughout, so you can have an appropriate fuse
for each appliance, plugged into high capacity sockets. This also
allows us to use our "ring main" system, which is the best way to do
house wiring I've seen.
Each floor (up to a maximum floor area per ring) has a ring of heavy
(2.5mm^2) cable laid in a loop, supplied by a 32A breaker. You can
hang as many sockets off this as you like. Each appliance then has
its own cable and fused plug, up to a max of 13A per appliance.
Although there's not much call for these, you can have 3kW on a
portable appliance and plug it into any socket in any house in the
country. It's a good system.
Although the ring main was originally developed to save copper
post-war, it's also a key part of our national passion for tea
drinking. A kitchen kettle is 3kW of sheer rapid boiling power and
we'd never be seen dead with that American abomination of the warm,
damp, Liptons bag in a cup.
We never went for aluminium wiring. Thank goodness.
We're not allowed sockets or light switches in bathrooms. However
"bathroom" literally meant a room with a bath in it, and shower rooms
never came under this rule. Recently things have changed and there's
now a more sensible system based on zones (is it reachable from the
bath or shower ?) and sockets are permitted with some rules.
Earth leakage breakers (RCD) came in in the early '70s but weren't
used widely until 1990-ish. Now all new fitments have a 100mA breaker
on the main panel and individual circuits may have 30mA RCDs where
useful (external sockets, kitchens, etc.) Better designed systems use
split load panels, where only half the circuits share the common
ground fault RCD, so that the lights and freezer don't go off if the
garden pond pump springs a leak.
>Do you have a safety (fault) ground (earth)?
Yes. All cable is three core, and everything gets bonded, right down
to the lampshades. There are also rules for wet rooms like kitchens
where metalwork must have supplementary bonding.
I sincerely believe that UK house wiring (to current standards) is the
world's best system for doing it. It's a simple system, but it's
efficient on materials and the standardisation amongst appliances is a
great convenience.
--
Die Gotterspammerung - Junkmail of the Gods
On Sun, 26 Oct 2003 01:40:10 +0100, Andy Dingley
<[email protected]> brought forth from the murky depths:
>On Sat, 25 Oct 2003 16:32:43 GMT, Larry Jaques <jake@di\/ersify.com>
>wrote:
>
>>Here, we have two lives and a ground.
>
>We have a similar system to that for on-site work.
>
>50V is "safe".
Sure, if you like being nibbled by the 'lectricity.
=====================================================================
-=Everything in Moderation,=- NoteSHADES(tm) glare guards
-=including moderation.=- http://www.diversify.com
=====================================================================
guess I didn't make myself clear, Doug. I live in San Jose, but had a
business in Santa Clara. The VOLTAGE is 208 in Santa Clara, as opposed
to 220 (or thereabouts) in San Jose. NOW do you understand what I was
getting at? I thought you'd understand my business was in an industrial
area since I had 3 phase power!!!
dave
Doug Miller wrote:
> In article <[email protected]>, Bay Area Dave <[email protected]> wrote:
>
>>If he lives in Santa Clara, CA, the power is only 208. I used to have a
>>business there, so I went with a 208V 3 phase 5HP motor on my compressor.
>>
>
> Dave, the key word there is "business". It's *very* rare in the US to have
> 3-phase power in a residence.
>
> --
> Regards,
> Doug Miller (alphageek-at-milmac-dot-com)
I can think of two benefits of 3-phase -
More HP in a smaller frame motor.
Reduced electrical cost both in demand and KW.
Keep in mind that having 220 in your shop doesn't mean you have 3-phase
available.
Erik
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
> plan on buying 220 machines when ever possible. While doing my research,
> I've heard people mention single phase and three phase power but without
the
> benefits or limitations of each. Can anyone help me understand this a
little
> bit more or point me in a direction? -mike
>
>
You should be able to look at the consumption meter and see what it says
also, you can call your utility co and ask them. If you have 3-Ph they will
know.
Erik
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> Is there anyway to determine what I have short of having an electrician
come
> out? Thanks for the responses. -mike
>
> "Erik Ahrens" <erikl_nospam_@_nospam_syserco.com> wrote in message
> news:[email protected]...
> > I can think of two benefits of 3-phase -
> > More HP in a smaller frame motor.
> > Reduced electrical cost both in demand and KW.
> >
> > Keep in mind that having 220 in your shop doesn't mean you have 3-phase
> > available.
> >
> > Erik
> >
> >
> > "Mike B" <[email protected]> wrote in message
> > news:[email protected]...
> > > I'm looking to purchase a cabinet saw. I have 220 in my shop currently
> and
> > > plan on buying 220 machines when ever possible. While doing my
research,
> > > I've heard people mention single phase and three phase power but
without
> > the
> > > benefits or limitations of each. Can anyone help me understand this a
> > little
> > > bit more or point me in a direction? -mike
> > >
> > >
> >
> >
>
>
Lots of larger offices and most all factories are fed with 3 phase because
it's cost effective and more efficient. Smaller buildings and residential
are fed with single phase.
220 is single phase. Your wise in utilizing it. Upgrading to 3-phase power
would require a whole new "service entrance", main panel, and perhaps "line
work" to replace the line transformer feeding your location.
Heck, you might not even have it available at the pole in your location.
If you're situation is substantial, and your so inclined, call up a local
electrical contractor that advertises "commercial and industrial" and talk
to their service department manager. I'm sure he'd be glad to talk with you
and clarify the finer points.
If you two figure out it's worth a look-over he'll come by or send someone
over to eyeball the location to see if it's feasible and makeup a quote.
It's that easy.
Hope this helps,
Jon Veeneman
"Mike B" <[email protected]> wrote in message
news:[email protected]...
> I'm looking to purchase a cabinet saw. I have 220 in my shop currently and
> plan on buying 220 machines when ever possible. While doing my research,
> I've heard people mention single phase and three phase power but without
the
> benefits or limitations of each. Can anyone help me understand this a
little
> bit more or point me in a direction? -mike
>
>
Look at the main breaker in your distribution panel. If it has two handles tied together then you gave 220v single phase. If there
are three , then you have 3 phase. If it is a residential installation, I doubt you have 3-phase power.
--
Al Reid
"It ain't what you don't know that gets you into trouble. It's what you know
for sure that just ain't so." --- Mark Twain
"Mike B" <[email protected]> wrote in message news:[email protected]...
> Is there anyway to determine what I have short of having an electrician come
> out? Thanks for the responses. -mike
>
> "Erik Ahrens" <erikl_nospam_@_nospam_syserco.com> wrote in message
> news:[email protected]...
> > I can think of two benefits of 3-phase -
> > More HP in a smaller frame motor.
> > Reduced electrical cost both in demand and KW.
> >
> > Keep in mind that having 220 in your shop doesn't mean you have 3-phase
> > available.
> >
> > Erik
> >
> >
> > "Mike B" <[email protected]> wrote in message
> > news:[email protected]...
> > > I'm looking to purchase a cabinet saw. I have 220 in my shop currently
> and
> > > plan on buying 220 machines when ever possible. While doing my research,
> > > I've heard people mention single phase and three phase power but without
> > the
> > > benefits or limitations of each. Can anyone help me understand this a
> > little
> > > bit more or point me in a direction? -mike
> > >
> > >
> >
> >
>
>
I looked into 3 phase too, back when I was working for a company that regularly
tossed 3p motors in the trash.
I did have 3 phase primaries on the street.
What I *might* have been able to get was 3p center tapped delta, 240 between
phases, (2) 120v phases and a wild leg (208 to ground). It only required one
extra transformer. It was still going to be expensive. I would need to install
a 3p service disconnect, rewire my current panel as a sub and install another
3p sub.
By the time I paid for the upgrade from the utility and upgraded my service I
figured I could buy a lifetime supply of single phase motors so I passed.
Where I live now I only have a single phase primary on the street so 3p is
pretty much out of the question.
There are tricks with capacitors that allow you to run 3p motors on single
phase but the lack of efficiency in this trick negates any saving a 3p motor
could get you. It might be a solution if you are getting the 3p equipment
virtually for free and you don't use it a lot.
Brian Elfert wrote:
>
> The reason I want to do this is for big equipment like wide belt sanders
> and big planers. Ever try finding a used wide belt sander in single
> phase? I've got a better chance at the lottery. Three phase sanders are
> a dime a dozen. You can get new wide belt sanders in 10HP single phase,
> but only 25" and the cost is about $8,000.
>
> The 20" Jet/Powermatic taiwanese planer for $2000 that is single phase is
> just junk compared to a used Powermatic. For $2,000 I could easily find
> an 18" or 20" old Powermatic with a three phase motor.
>
> Very rarely you will see a Powermatic planer with single phase motor but
> the owners price them sky high because they know how rare the single phase
> beasts are.
>
> Brian Elfert
You state that the reason it the need for "big" equipment that has the
advantage
of being cheaper up front (purchase price) compared to (lesser quality)
single phase
equipment.
I'm not sure of your intended use (production vs. sporadic home type
use), but in general
the most cost effective way to take advantage of the "cheaper" three
phase equipment
is with phase convertors. As stated before you do lose all the
efficiency gains of true
three phase but if the equipment is only actually running for a tiny
fraction of the day
these savings are invisible. Several neighbors have 5-7hp lathes and
mills in their garages
that they power with rotary convertors (made from a spare three phase
motor) that work
just fine. These things are only used for short times and the price of a
surplus three phase
lathe is far cheaper than any equivalent 1 phase tool.
If I was planning on what you are intending, I'd just get the 3-phase
equipment and live with a
phase convertor. Should the need arise later for true three phase, you
probably can get it installed
if the service is near by for several thousand dollars.
-Bruce
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
[email protected] (Gfretwell) writes:
>I looked into 3 phase too, back when I was working for a company that regularly
>tossed 3p motors in the trash.
>I did have 3 phase primaries on the street.
>What I *might* have been able to get was 3p center tapped delta, 240 between
>phases, (2) 120v phases and a wild leg (208 to ground). It only required one
>extra transformer. It was still going to be expensive. I would need to install
Would this type of service even work for three phase equipment?
The reason I want to do this is for big equipment like wide belt sanders
and big planers. Ever try finding a used wide belt sander in single
phase? I've got a better chance at the lottery. Three phase sanders are
a dime a dozen. You can get new wide belt sanders in 10HP single phase,
but only 25" and the cost is about $8,000.
The 20" Jet/Powermatic taiwanese planer for $2000 that is single phase is
just junk compared to a used Powermatic. For $2,000 I could easily find
an 18" or 20" old Powermatic with a three phase motor.
Very rarely you will see a Powermatic planer with single phase motor but
the owners price them sky high because they know how rare the single phase
beasts are.
Brian Elfert
>>What I *might* have been able to get was 3p center tapped delta, 240 between
>>phases, (2) 120v phases and a wild leg (208 to ground). It only required one
>>extra transformer. It was still going to be expensive. I would need to
>install
>
>Would this type of service even work for three phase equipment?
>
As long as the equipment is capable of being wired for 240v 3p (most do) it
won't know about the center tap.
The center tap is only used for the 120v loads. This arrangement also gives you
the 240v single phase the other equipment in your house expects.
It was what the utility advised but they weren't anxious to do it. It came down
to money in the end. I could have got an upgrade to 400a 1p for free but the 3p
was just called "expensive" by the engineer at PEPCO and neither of us pursued
it farther. I didn't actually go to the sales office for how expensive it would
be. Of course you also have to add the price of the service disconnect, main
panel rewiring and the extra 3p panel.
You might actually be able to get by with the capacitor trick (I think it is
4mfd per HP if memory serves) although a commercial phase converter is the
better solution.
I did get a 3p 3/4hp (3330 disk drive) motor spinning with a 3mfd capacitor but
I never really used it for anything.
Gfretwell wrote:
> There are tricks with capacitors that allow you to run 3p motors on single
> phase but the lack of efficiency in this trick negates any saving a 3p motor
> could get you. It might be a solution if you are getting the 3p equipment
> virtually for free and you don't use it a lot.
>
>
That's what I did on my 3 hp 3 phase milling machine, but it
wasn't nearly free :) So far I have not noticed any
drawbacks to the simple cheap way. If I was running the
machine at full capacity in a commercial environment I
probably would.
On my 3 hp 3 phase lathe, I got a VFD because I wanted
variable speed control. Then I found out how nice they are
for controlled rate stopping and starting and a bunch of
other things. I would even use one on a metalworking lathe
if I had three phase power. I probably wouldn't bother with
a VFD on wood working tools, although it would be tempting
if I got a ww lathe for turning large diameter items.
Rico
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
Gfretwell wrote...
> I looked into 3 phase too, back when I was working for a company that
> regularly tossed 3p motors in the trash.
...
> By the time I paid for the upgrade from the utility and upgraded my
> service I figured I could buy a lifetime supply of single phase motors
> so I passed.
...
> There are tricks with capacitors that allow you to run 3p motors on
> single phase but the lack of efficiency in this trick negates any saving
> a 3p motor could get you.
You missed out.
You could have used one of the three-phase motors as an "idler motor" to
generate the third phase. Then, by adding capacitance to balance the
inter-phase voltages and power factor for your typical loads, you could
have used this "rotary converter" to power your three-phase equipment at
full capacity.
Jim
"Brian Elfert" wrote in message news
> I'm pretty sure the power poles running along the front of my lot are
> three phase. I really doubt the power company would install a transformer
> and the underground feed to my shop that would provide me with three phase
> power, even if it is there. If they did do it, they would probably charge
an arm and a leg.
Actually if the situation warrents it (demand is there) I don't believe they
charge to provide power (up to the "service wiring"). Naturally they aren't
going to do all that for a heating pad in fido's dog house!
> I actually called one time to inquire about three phase and just got
> shuffled from department to department and gave up at the time.
If you called your local power co. I can believe that. You'd have gotten
some real answers from a contractor. You know.. in regards to quoting a
possible job.
Jon Veeneman
"Andy Dingley" <[email protected]> wrote in message
news:[email protected]...
> On Fri, 24 Oct 2003 15:58:47 GMT, [email protected] (Doug Miller)
> wrote:
>
> >It's *very* rare in the US to have
> >3-phase power in a residence.
>
> I thought some of you guys had (domestic) heating that ran off it ?
>
> Here in the UK it depends how your power is delivered. If it's
> underground (nearly everyone) then it's a serious spend to get 3
> phase. If it's an overhead feed (just the rustics) then it's a lot
> cheaper as there's normally line-of-sight to a suitable transformer.
>
> --
> Die Gotterspammerung - Junkmail of the Gods
Normally, Three phase is not even in the neighborhood, so it is not an
option, no matter the cost. I suppose they would string new lines, if you
asked them, with a big checkbook!
--
Jim in NC
"Al Reid" <[email protected]> wrote in message
news:[email protected]...
> Look at the main breaker in your distribution panel. If it has two
handles tied together then you gave 220v single phase. If there
> are three , then you have 3 phase. If it is a residential installation, I
doubt you have 3-phase power.
>
> --
>
Might not help. Some main breakers are a one molded-one piece affair. Not
easy to tell the difference by just looking at it. On the other hand there
should be some printing on the breaker that will tell the difference.
Greg