Scott Lurndal wrote:
>>> Surely not in a woodworking shop. Much more likely to be
>>> two-hots +
>>> grounding for single-phase, three-hots + grounding for 3-phase.
--------------------------------------------
"Mike Marlow" wrote:
>> You have not been paying attention to the NEC have you?
---------------------------------------------
"John McCoy" wrote:
>
> Scott is correct with respect to 3-phase. 3 hots, possibly a
> ground. No neutral.
>
> 240 single phase is trickier - often in modern wiring there's
> a neutral, so you can use it as either two 120 circuits or
> one 240 circuit. I don't really like that, but it helps stop
> hacks from using one leg of the 240 and ground as a 120 circuit.
-----------------------------------------------
What is being totally forgotten are the "Y" services.
480V/277V/3PH/4W/60HZ and 208V/120V/3PH/4W/60HZ.
Both require 3 "hots" (L1, L2, L3), neutral and ground.
I would expect any school or other light commerical
(shopping centers, etc) buildings built in the last 40 years to
be supplied with 208V/120V.
There are lots of reasons including lower cost and SAFETY.
Lew
With the prospect of it being 3 phase, if the jointer can be purchased at a reasonable price, then look for a replacement motor: single phase, 110V/220V, 3450 RPM, 1hp or 1.5hp, 5/8" shaft. You'd need to change the switch to single phase, also.
http://www.ebay.com/itm/Marathon-1-1-2-HP-Single-Phase-Motor-Fr-56-JUC-56B34D5530E-3450-RPM-115-208-230-/111504633720?pt=LH_DefaultDomain_0&hash=item19f631af78
http://www.ebay.com/itm/Vintage-Leland-1-HP-Single-Phase-Electric-Motor-/361100399693
http://www.ebay.com/itm/BALDOR-SINGLE-PHASE-VL3513-1-1-2-HP-3450-RPM-ELECTRIC-MOTOR-/121459855059
http://www.ebay.com/itm/Baldor-Single-Phase-Motor-VL3509-1-HP-3450-RPM-5-8-SHAFT-/131305703755
Sonny
On 11/6/2014 8:55 PM, Bill wrote:
> Mike Marlow wrote:
>> Bill wrote:
>>
>>> Looking at the bottom of the connector, the "30A 600VAC" was centered
>>> accross the top, and the
>>> 30 250V was centered accross the bottom. I accept your analysis
>>> below as probably correct.
>>> Being an "industrial strength" 8" Rockwell jointer, the 3-phase
>>> feature makes sense.
>>>
>> It could well be Bill, but the markings on the plug cannot steer you
>> to any
>> conclusion. That plug could equally well have been used for a 30A (10
>> guage) 240V single phase configuration. You'd really want to see the
>> motor
>> plate and any other specuation is just that - speculation.
>
> I have a hunch a greater percentage were probably made for 3-phase than
> 1-phase, no? Someone must have some
> insight into this. I saw numerous rebuilt ones online--and the "phase"
> wasn't mentioned in any of them.
>
>
>
>>
>
If you have the plug in your hand or can be - how many lugs plug into
the other half ? What shape are they. Orientation - twist is
circle. You mentioned that.
3 phase typically have 4 or more lugs/pins/sockets... Single phase has
3 if in a school. And likely 220 if in a school.
For a large joiner, 2 or 3 phase is likely and likely wanted as well.
2 phase is real 3 phase with a missing leg. It isn't single phase 220.
I have 1600 feet drop of 2phase high voltage. I use one leg for two
transformers. The other leg can be cut off at the highway and used
as a safety line - fending off tree limbs.
The two phase high voltage generated 3 phase locally when a saw mill sat
in my side yard. I mean a Saw Mill of industrial size. It was moved
out before I came.
Martin
Martin
Bill <[email protected]> wrote in news:[email protected]:
> I found a tool that has a plug upon which it says: 30A 600VAC 30 250V
> Does that mean it is 3-phase?
>
> Yes, I know I should be looking at a tag on the motor, but it is
> inaccessible at the moment.
I'm guessing that the zero in the second "30" has a slash or vertical bar through it, in which
case, yes, it's 3-phase. Look at this image, for example:
http://cds.a9t2h4q7.hwcdn.net/main/store/20090519001/items/media/Electrical/passseymo
ur/ProductLarge/5760.jpg
You can also tell whether a plug or receptacle is single-phase or 3-phase, as well as its
rated voltage and amperage, by comparing it to a NEMA plug configuration chart.
Bill <[email protected]> wrote in news:[email protected]:
> I found a tool that has a plug upon which it says: 30A 600VAC 30 250V
> Does that mean it is 3-phase?
That's a peculiar set of numbers to see on a plug.
I am going to guess here that the 250V is a DC rating (altho
it is unusual to see that on a connector you occasionally
will). So your motor is probably a 600V 3-phase motor.
The second 30 (without an "A" after it) is probably an
"O" with a slash thru it, indicating 3 phase.
John
"Mike Marlow" <[email protected]> wrote in news:m3qpju$bfq$1@dont-
email.me:
> You are correct in that - devices like dryers that split off 110v are really
> what demand a neutral and a ground, but it is increasingly becoming common
> to require that same 4 wire configuration for other 240v applications.
For combined 240V/120V loads, sure. For a pure 240V load? Doubtful. Can you cite examples
where a perfectly useless neutral wire is required for a pure 240V load?
> I
> will step back and say that the NEC may well make an excemption for devices
> like say a compressor. I probably should have simply stated that a 4 wire
> configuration is prefered.
Citation, please...
"Mike Marlow" <[email protected]> wrote in news:m3qkvi$nv9$1
@dont-email.me:
> Scott Lurndal wrote:
>> Surely not in a woodworking shop. Much more likely to be two-hots +
>> grounding for single-phase, three-hots + grounding for 3-phase.
>
> You have not been paying attention to the NEC have you?
Scott is correct with respect to 3-phase. 3 hots, possibly a
ground. No neutral.
240 single phase is trickier - often in modern wiring there's
a neutral, so you can use it as either two 120 circuits or
one 240 circuit. I don't really like that, but it helps stop
hacks from using one leg of the 240 and ground as a 120 circuit.
John
"Lew Hodgett" <[email protected]> wrote in news:54613a23$0$39503
[email protected]:
> What is being totally forgotten are the "Y" services.
>
> 480V/277V/3PH/4W/60HZ and 208V/120V/3PH/4W/60HZ.
>
> Both require 3 "hots" (L1, L2, L3), neutral and ground.
I don't think you'd find a motor wired as a Y connection,
tho. Motors are usually in the delta configuration (altho
there some that start in a Y configuration and switch to
delta to run, you still just see the 3 hot leads externally,
there's no neutral connection).
John
"Mike Marlow" <[email protected]> writes:
>Martin Eastburn wrote:
>
>>
>> 3 phase typically have 4 or more lugs/pins/sockets... Single phase
>> has 3 if in a school. And likely 220 if in a school.
>
>Older wiring would likely have only 3 lugs even in a 240v application, but
>if the wiring had been updated at all, it might likely have been converted
>to the current standard of 4 wire for 240v. Two hots, neutral, and ground.
>
Surely not in a woodworking shop. Much more likely to be two-hots + grounding
for single-phase, three-hots + grounding for 3-phase.
I'm tempted to snap up this Marathon motor, though I don't need one, now, simply because it's so inexpensive. Never know when/if my 20 yr old Powermatic jointer motor may quit.
Sonny
> http://www.ebay.com/itm/Marathon-1-1-2-HP-Single-Phase-Motor-Fr-56-JUC-56B34D5530E-3450-RPM-115-208-230-/111504633720?pt=LH_DefaultDomain_0&hash=item19f631af78
>
On 11/4/2014 2:24 PM, Bill wrote:
> I found a tool that has a plug upon which it says: 30A 600VAC 30 250V
> Does that mean it is 3-phase?
>
> Yes, I know I should be looking at a tag on the motor, but it is
> inaccessible at the moment.
>
> Thanks,
> Bill
This may well be a motor that is two voltages. Why the same current ? hum.
Going to have to look. Three phase is full of many many wires. At
least six maybe four and maybe 12 or so.
A single phase will have two wires and an earth (maybe). Is it a big
one a 30hp ? 1800 watts one way and 7500 the other.
Best look. and post a picture somewhere for all to see.
Martin
On 11/04/2014 2:24 PM, Bill wrote:
> I found a tool that has a plug upon which it says: 30A 600VAC 30 250V
> Does that mean it is 3-phase?
>
> Yes, I know I should be looking at a tag on the motor, but it is
> inaccessible at the moment.
...
Doesn't prove it, no, but at those amperages there'd be a good chance't
it would be.
Better klew could be the plug configuration--number prongs, shape...
--
dpb wrote:
> On 11/04/2014 2:24 PM, Bill wrote:
>> I found a tool that has a plug upon which it says: 30A 600VAC 30 250V
>> Does that mean it is 3-phase?
>>
>> Yes, I know I should be looking at a tag on the motor, but it is
>> inaccessible at the moment.
> ...
>
> Doesn't prove it, no, but at those amperages there'd be a good
> chance't it would be.
>
> Better klew could be the plug configuration--number prongs, shape...
It was one of those that you push in and twist. At the time, I thought
what I wrote down
above would tell the whole story. It's actually a machine from a high
school.
>
> --
>
Martin Eastburn wrote:
> On 11/4/2014 2:24 PM, Bill wrote:
>> I found a tool that has a plug upon which it says: 30A 600VAC 30 250V
>> Does that mean it is 3-phase?
>>
>> Yes, I know I should be looking at a tag on the motor, but it is
>> inaccessible at the moment.
>>
>> Thanks,
>> Bill
> This may well be a motor that is two voltages. Why the same current ?
> hum.
>
> Going to have to look. Three phase is full of many many wires. At
> least six maybe four and maybe 12 or so.
>
> A single phase will have two wires and an earth (maybe). Is it a big
> one a 30hp ? 1800 watts one way and 7500 the other.
>
> Best look. and post a picture somewhere for all to see.
It was from an (old) Rockwell jointer, having an 8" by 5.5' bed,at an
auction. Serial#: 124-6065 (in case that suggests a date or anything).
It had a "heavy" power cord. Its location among other tools made it
inaccessible. I could not open it's "power box" with my hands ; it may
have been slightly smashed in. It was previously owned by a school
district near Indianapolis. On a day with fewer conflicts, I would have
tried harder to attend the auction if I knew it wasn't 3-phase. The
available evidence seemed to suggest 3 phase.
Bill
>
> Martin
>
>
John McCoy wrote:
> Bill <[email protected]> wrote in news:[email protected]:
>
>> I found a tool that has a plug upon which it says: 30A 600VAC 30 250V
>> Does that mean it is 3-phase?
Looking at the bottom of the connector, the "30A 600VAC" was centered
accross the top, and the
30 250V was centered accross the bottom. I accept your analysis below
as probably correct.
Being an "industrial strength" 8" Rockwell jointer, the 3-phase feature
makes sense.
Thanks!
Bill
> That's a peculiar set of numbers to see on a plug.
>
> I am going to guess here that the 250V is a DC rating (altho
> it is unusual to see that on a connector you occasionally
> will). So your motor is probably a 600V 3-phase motor.
> The second 30 (without an "A" after it) is probably an
> "O" with a slash thru it, indicating 3 phase.
>
> John
Bill wrote:
>
> Looking at the bottom of the connector, the "30A 600VAC" was centered
> accross the top, and the
> 30 250V was centered accross the bottom. I accept your analysis
> below as probably correct.
> Being an "industrial strength" 8" Rockwell jointer, the 3-phase
> feature makes sense.
>
It could well be Bill, but the markings on the plug cannot steer you to any
conclusion. That plug could equally well have been used for a 30A (10
guage) 240V single phase configuration. You'd really want to see the motor
plate and any other specuation is just that - speculation.
--
-Mike-
[email protected]
Mike Marlow wrote:
> Bill wrote:
>
>> Looking at the bottom of the connector, the "30A 600VAC" was centered
>> accross the top, and the
>> 30 250V was centered accross the bottom. I accept your analysis
>> below as probably correct.
>> Being an "industrial strength" 8" Rockwell jointer, the 3-phase
>> feature makes sense.
>>
> It could well be Bill, but the markings on the plug cannot steer you to any
> conclusion. That plug could equally well have been used for a 30A (10
> guage) 240V single phase configuration. You'd really want to see the motor
> plate and any other specuation is just that - speculation.
I have a hunch a greater percentage were probably made for 3-phase than
1-phase, no? Someone must have some
insight into this. I saw numerous rebuilt ones online--and the "phase"
wasn't mentioned in any of them.
>
Bill wrote:
> Mike Marlow wrote:
>>>
>> It could well be Bill, but the markings on the plug cannot steer you
>> to any conclusion. That plug could equally well have been used for
>> a 30A (10 guage) 240V single phase configuration. You'd really want
>> to see the motor plate and any other specuation is just that -
>> speculation.
>
> I have a hunch a greater percentage were probably made for 3-phase
> than 1-phase, no? Someone must have some
> insight into this. I saw numerous rebuilt ones online--and the
> "phase" wasn't mentioned in any of them.
Good question - I really don't have any experience with a machine of this
size. It seems it could be likely that the most of them of this size -
especially coming out of a school, could well be three phase.
--
-Mike-
[email protected]
Martin Eastburn wrote:
>
> 3 phase typically have 4 or more lugs/pins/sockets... Single phase
> has 3 if in a school. And likely 220 if in a school.
Older wiring would likely have only 3 lugs even in a 240v application, but
if the wiring had been updated at all, it might likely have been converted
to the current standard of 4 wire for 240v. Two hots, neutral, and ground.
--
-Mike-
[email protected]
"Martin Eastburn" wrote
For a large joiner, 2 or 3 phase is likely and likely wanted as well.
2 phase is real 3 phase with a missing leg. It isn't single phase 220.
**********************
Watt?
2 phase is nothing. It makes a machine sit there and hum.
Normal residential 220, or 240, is single phase. Phase indicates how many
lines have electricity in them with a sine waveform of voltage over time.
Three phase has three lines, and each have their own sine wave going that
are 120 degrees out of sync with each other.
Residential 240 has one hot line coming to the transformer. It has one sine
wave. The transformer is center tapped and the juice is sent down two hot
lines to your house. It is the same sine wave that is now 180 degrees out
of phase. Still single phase. Ground to either line is 120. Line to line
is 240. Still single phase.
Then there is a mixed three phase, as was in my school. Three hots, three
sine waves. We did not have single phase 240. If you were to tap from one
hot line to another, you got 208 volts. Y tap, I think they called it. I
don't recall what the 110 volt was from hot to ground. Around 113, I think.
Bad idea to run a motor intended for 240 on 208, when it is being used at
close to its rated maximum load. Decreased voltage causes it to draw more
amps, and more amps means hot and eventually burn out.
---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com
On 11/06/2014 8:55 PM, Bill wrote:
...
> I have a hunch a greater percentage were probably made for 3-phase than
> 1-phase, no? Someone must have some
> insight into this. I saw numerous rebuilt ones online--and the "phase"
> wasn't mentioned in any of them.
...
Overall, I'd say likely but probably not by as large a percentage as one
might think. There were quite a lot sold for individual shops as well
as small shops w/o 3-phase.
But, you can reliably bet if it comes from a large shop, commercial
factory setting, surplus from military or school it will be 3-phase.
Again, if you can get a deal, don't worry about it too much; just put a
single phase 1 or 2 hp motor on it and go on or if you're going to build
a sizable shop invest in 3-phase converter and you can pick up other
stuff as you find it and already be ready.
And, you don't need new starter/switch as somebody said to run it on
single-phase. Presuming it has the original magnetic motor starter or a
similar replacement, simply disconnect the feed for the unused "phases"
and replace the heaters with proper size for the motor you put on it.
They're readily available and not expensive.
I've a half-dozen pieces of equipment all with such a setup; works just
fine...back 30 year ago I found a deal on a bunch of salvaged Rockwell
starters and bought 10 of 'em at $10/ea. Backfitted everything in the
shop with them replacing all the mechanical switches. Wished many times
since I'd bought the whole lot of 'em.
--
On 11/07/2014 8:12 AM, dpb wrote:
...
> And, you don't need new starter/switch as somebody said to run it on
> single-phase. Presuming it has the original magnetic motor starter or a
> similar replacement, simply disconnect the feed for the unused "phases"
> and replace the heaters with proper size for the motor you put on it.
> They're readily available and not expensive.
...
That is, instead of having three switched leads, you've now got two
(presuming you run on 240V) and just an extra unused contact. For 120V
you've got two unused but so what?; when the cover's on, nobody can
tell... :)
The worst that can happen is that there's an outside chance it has a 200
V minimum coil voltage and you want to run on 110V. In that case you
can replace that relay but my recommendation would be to go to 240 V
instead even if you do have to run a new branch circuit. You'll be glad
you did down the road.
--
Scott Lurndal wrote:
> "Mike Marlow" <[email protected]> writes:
>> Martin Eastburn wrote:
>>
>>>
>>> 3 phase typically have 4 or more lugs/pins/sockets... Single phase
>>> has 3 if in a school. And likely 220 if in a school.
>>
>> Older wiring would likely have only 3 lugs even in a 240v
>> application, but if the wiring had been updated at all, it might
>> likely have been converted to the current standard of 4 wire for
>> 240v. Two hots, neutral, and ground.
>>
>
> Surely not in a woodworking shop. Much more likely to be two-hots +
> grounding for single-phase, three-hots + grounding for 3-phase.
You have not been paying attention to the NEC have you?
--
-Mike-
[email protected]
On 11/10/2014 9:20 AM, Mike Marlow wrote:
> Scott Lurndal wrote:
>> "Mike Marlow"<[email protected]> writes:
>>> Martin Eastburn wrote:
>>>
>>>>
>>>> 3 phase typically have 4 or more lugs/pins/sockets... Single phase
>>>> has 3 if in a school. And likely 220 if in a school.
>>>
>>> Older wiring would likely have only 3 lugs even in a 240v
>>> application, but if the wiring had been updated at all, it might
>>> likely have been converted to the current standard of 4 wire for
>>> 240v. Two hots, neutral, and ground.
>>>
>>
>> Surely not in a woodworking shop. Much more likely to be two-hots +
>> grounding for single-phase, three-hots + grounding for 3-phase.
>
> You have not been paying attention to the NEC have you?
Nor have I in much detail but unless there's a dual-voltage load on the
circuit (clothes dryer is the prototypical example) there's no function
whatsoever for the neutral and I thought NEC still gave that exemption
for such circuits???
I'd certainly _NEVER_ rewire such to add a completely superfluous wire
simply to be there. It'll never be connected to anything, what more
have any current, so what's the point?
--
dpb wrote:
> On 11/10/2014 9:20 AM, Mike Marlow wrote:
>> Scott Lurndal wrote:
>>> "Mike Marlow"<[email protected]> writes:
>>>> Martin Eastburn wrote:
>>>>
>>>>>
>>>>> 3 phase typically have 4 or more lugs/pins/sockets... Single
>>>>> phase has 3 if in a school. And likely 220 if in a school.
>>>>
>>>> Older wiring would likely have only 3 lugs even in a 240v
>>>> application, but if the wiring had been updated at all, it might
>>>> likely have been converted to the current standard of 4 wire for
>>>> 240v. Two hots, neutral, and ground.
>>>>
>>>
>>> Surely not in a woodworking shop. Much more likely to be two-hots
>>> + grounding for single-phase, three-hots + grounding for 3-phase.
>>
>> You have not been paying attention to the NEC have you?
>
> Nor have I in much detail but unless there's a dual-voltage load on
> the circuit (clothes dryer is the prototypical example) there's no
> function whatsoever for the neutral and I thought NEC still gave that
> exemption for such circuits???
You are correct in that - devices like dryers that split off 110v are really
what demand a neutral and a ground, but it is increasingly becoming common
to require that same 4 wire configuration for other 240v applications. I
will step back and say that the NEC may well make an excemption for devices
like say a compressor. I probably should have simply stated that a 4 wire
configuration is prefered.
--
-Mike-
[email protected]
On 11/10/2014 10:40 AM, Mike Marlow wrote:
> dpb wrote:
>> On 11/10/2014 9:20 AM, Mike Marlow wrote:
>>> Scott Lurndal wrote:
>>>> "Mike Marlow"<[email protected]> writes:
>>>>> Martin Eastburn wrote:
>>>>>
>>>>>>
>>>>>> 3 phase typically have 4 or more lugs/pins/sockets... Single
>>>>>> phase has 3 if in a school. And likely 220 if in a school.
>>>>>
>>>>> Older wiring would likely have only 3 lugs even in a 240v
>>>>> application, but if the wiring had been updated at all, it might
>>>>> likely have been converted to the current standard of 4 wire for
>>>>> 240v. Two hots, neutral, and ground.
>>>>>
>>>>
>>>> Surely not in a woodworking shop. Much more likely to be two-hots
>>>> + grounding for single-phase, three-hots + grounding for 3-phase.
>>>
>>> You have not been paying attention to the NEC have you?
>>
>> Nor have I in much detail but unless there's a dual-voltage load on
>> the circuit (clothes dryer is the prototypical example) there's no
>> function whatsoever for the neutral and I thought NEC still gave that
>> exemption for such circuits???
>
> You are correct in that - devices like dryers that split off 110v are really
> what demand a neutral and a ground, but it is increasingly becoming common
> to require that same 4 wire configuration for other 240v applications. I
> will step back and say that the NEC may well make an excemption for devices
> like say a compressor. I probably should have simply stated that a 4 wire
> configuration is prefered.
I'd reemphasize that _ANY_ 240V-only load has no neutral
connection--there's nowhere for the neutral to be connected at the load
end. The one place in woodshop or the like is the very occasional
device like the bandsaw with an auxiliary light bulb to provide local
illumination.
Again, I'm not saying NEC hasn't eliminated the exemption; I've not read
the newer Codes thru from cover to cover but it's just not needed for
the jointer, tablesaw, etc., etc., etc., ...
--
Doug Miller wrote:
> "Mike Marlow" <[email protected]> wrote in
> news:m3qpju$bfq$1@dont-
> email.me:
>
>> You are correct in that - devices like dryers that split off 110v
>> are really what demand a neutral and a ground, but it is
>> increasingly becoming common to require that same 4 wire
>> configuration for other 240v applications.
>
> For combined 240V/120V loads, sure. For a pure 240V load? Doubtful.
> Can you cite examples where a perfectly useless neutral wire is
> required for a pure 240V load?
Sorry Doug - can't cite the NEC on this. The only thing I can say is that
my compressor specified 4 wire and there is no 120v load off of it. Just
30A 4 wire.
--
-Mike-
[email protected]
On 11/10/2014 4:20 PM, Lew Hodgett wrote:
> Scott Lurndal wrote:
>
>>>> Surely not in a woodworking shop. Much more likely to be
>>>> two-hots +
>>>> grounding for single-phase, three-hots + grounding for 3-phase.
>
> --------------------------------------------
>
> "Mike Marlow" wrote:
>
>>> You have not been paying attention to the NEC have you?
> ---------------------------------------------
>
> "John McCoy" wrote:
>>
>> Scott is correct with respect to 3-phase. 3 hots, possibly a
>> ground. No neutral.
>>
>> 240 single phase is trickier - often in modern wiring there's
>> a neutral, so you can use it as either two 120 circuits or
>> one 240 circuit. I don't really like that, but it helps stop
>> hacks from using one leg of the 240 and ground as a 120 circuit.
> -----------------------------------------------
>
> What is being totally forgotten are the "Y" services.
>
> 480V/277V/3PH/4W/60HZ and 208V/120V/3PH/4W/60HZ.
>
> Both require 3 "hots" (L1, L2, L3), neutral and ground.
>
> I would expect any school or other light commerical
> (shopping centers, etc) buildings built in the last 40 years to
> be supplied with 208V/120V.
>
> There are lots of reasons including lower cost and SAFETY.
>
> Lew
>
>
>
Right - military and police / hospital tend to have delta/delta
transformers - allowing a leg in primary and/or secondary to be lost
and continue to deliver 66% of the rated power. These need it all of
the time customers over rate their transformers so the 60% is their real
need.
Schools go on low budgets and save on copper runs of large wire.
You can bet that every machine is GROUNDED. So if Three phase its 4 or
5 wire.
In industry we used 1000 amp /leg - 3 phase - 5 wire ground and neutral
from the box. Some local codes require 4 some 5 and the 5 was a super
class that passed Europe as well. Those Hubble plugs were monsters.
Most customers wired directly to the panel or overhead Buss Bars power box.
Martin
On Tue, 04 Nov 2014 18:43:34 -0500, Bill <[email protected]>
wrote:
>dpb wrote:
>> On 11/04/2014 2:24 PM, Bill wrote:
>>> I found a tool that has a plug upon which it says: 30A 600VAC 30 250V
>>> Does that mean it is 3-phase?
>>>
>>> Yes, I know I should be looking at a tag on the motor, but it is
>>> inaccessible at the moment.
>> ...
>>
>> Doesn't prove it, no, but at those amperages there'd be a good
>> chance't it would be.
>>
>> Better klew could be the plug configuration--number prongs, shape...
>
>It was one of those that you push in and twist. At the time, I thought
>what I wrote down
>above would tell the whole story. It's actually a machine from a high
>school.
Twist lock doesn't tell much. They come in all voltages and phases
(generally at the higher currents).
You can match your plug to these charts:
Twist-lock: http://www.quail.com/locking_nema_chart.aspx
Normal: http://www.quail.com/nema_chart.aspx
That is why milk producing dairies run 2 phase on their stuff -
And the large saw mill that once had this land as it's own used
two phase.
One uses 2 phase and generates a third automatically. Inverted V
or open delta is the way it is done.
Martin
On 11/7/2014 6:55 AM, Morgans wrote:
>
>
> "Martin Eastburn" wrote
>
> For a large joiner, 2 or 3 phase is likely and likely wanted as well.
> 2 phase is real 3 phase with a missing leg. It isn't single phase 220.
>
> **********************
> Watt?
>
> 2 phase is nothing. It makes a machine sit there and hum.
>
> Normal residential 220, or 240, is single phase. Phase indicates how
> many lines have electricity in them with a sine waveform of voltage over
> time.
>
> Three phase has three lines, and each have their own sine wave going
> that are 120 degrees out of sync with each other.
>
> Residential 240 has one hot line coming to the transformer. It has one
> sine wave. The transformer is center tapped and the juice is sent down
> two hot lines to your house. It is the same sine wave that is now 180
> degrees out of phase. Still single phase. Ground to either line is
> 120. Line to line is 240. Still single phase.
>
> Then there is a mixed three phase, as was in my school. Three hots,
> three sine waves. We did not have single phase 240. If you were to tap
> from one hot line to another, you got 208 volts. Y tap, I think they
> called it. I don't recall what the 110 volt was from hot to ground.
> Around 113, I think.
>
> Bad idea to run a motor intended for 240 on 208, when it is being used
> at close to its rated maximum load. Decreased voltage causes it to draw
> more amps, and more amps means hot and eventually burn out.
>
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