"Jay Giuliani" <jrgiuliani@verizon.net> wrote in news:MdPdl.1150$Aw2.892
@nwrddc02.gnilink.net:
> If it is a single phase motor it won't reverse.
>
> Think about all those two prong corded ac 115 VAC tools......
>
> You can reverse rotation on a three phase mpotor but as the other folks
> said, why?
>
If you reverse the rotation, doesn't it reattach the piece you cut off?
Puckdropper
--
On Usenet, no one can hear you laugh. That's a good thing, though, as some
writers are incorrigible.
To email me directly, send a message to puckdropper (at) fastmail.fm
On 1/15/2009 8:07 AM Robatoy mumbled something about the following:
>
> On Jan 15, 7:06 am, "dadiOH" <dad...@invalid.com> wrote:
>> -MIKE- wrote:
>>> boynton...@gmail.com wrote:
>>>> Just wondering whether it could be done.
>>> I've always wondered the same thing.
>> Strange, I've spent my life NOT wondering :)
>>
>> --
>>
>> dadiOH
>> ____________________________
>>
>> dadiOH's dandies v3.06...
>> ...a help file of info about MP3s, recording from
>> LP/cassette and tips & tricks on this and that.
>> Get it athttp://mysite.verizon.net/xico
>
> I find that question often interrupts dreams of a sexual nature.
> It is just when the blond swedish twins start unbuttoning their tops
> that
> the question about motor reversal rears its ugly little head.
Shredded wheat and milk through the nose is painful. Oh, and you owe me
a keyboard.
--
Odinn
RCOS #7 SENS BS #154
Andrew Erickson wrote:
> I do sincerely hope the original poster isn't intending to use the
> radial saw in reverse; that sounds like a recipe for disaster. I
> suppose if one wanted the blade on the opposite side of the traveler one
> would need to reverse the rotation of the motor (and probably reengineer
> the mount some), but otherwise...ouch.
Yes, I hope the idea isn't to simply reverse the blade and do crosscuts
in the same manner as before! Apart from the saw throwing all the
sawdust in your face, the blade would be trying to force the wood *away*
from the fence, causing binds, kickback, and other unfortunate side
effects such as injury or death.
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On Mon, 19 Jan 2009 21:54:24 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:
>Electrically reversing the motor is probably psosible
>(usually these have brush-style motors, you could
>reverse the brush polarities);
I assume this is an AC motor. Don't the brush polarities reverse 60
times per second already? Or possibly I'm not understanding what
you're saying?
Tom Veatch
Wichita, KS
USA
On Jan 14, 5:13=A0pm, boynton...@gmail.com wrote:
> Just wondering whether it could be done.
As others have noted, you might be able to swivel the
sawhead 180 degrees (would only be safe if you
also repositioned the fence to the far-from-column
side of the work).
Electrically reversing the motor is probably psosible
(usually these have brush-style motors, you could
reverse the brush polarities); the gears, however,
would NOT necessarily mesh neatly with the newly
reversed drive, and some kinds of spiral-cut gears
could cause the blade position to destabilize.
When I got my Delta Band saw - it came from a good dealer in
a state. The manager was at a conference and the guys shipped
a bandsaw and a motor. The motor had sawdust on it and wasn't
in a new box. Hum - stripped it off something. Looks new.
I installed it and the saw ran backwards. Just like a lathe....
I swapped the wires as mentioned - inside it was marked - and
then the saw cut wood. I then converted it to 14".
So wood working motors as others reverse.
Martin
-MIKE- wrote:
> boyntonstu@gmail.com wrote:
>> Just wondering whether it could be done.
>
> I've always wondered the same thing.
>
>
If it is a single phase motor it won't reverse.
Think about all those two prong corded ac 115 VAC tools......
You can reverse rotation on a three phase mpotor but as the other folks
said, why?
"Tom Veatch" <nope@nada.org> wrote in message
news:402cn4tto6sscu17j6rfkulhr2tgchosg0@4ax.com...
> On Mon, 19 Jan 2009 21:54:24 -0800 (PST), whit3rd <whit3rd@gmail.com>
> wrote:
>
>>Electrically reversing the motor is probably psosible
>>(usually these have brush-style motors, you could
>>reverse the brush polarities);
>
> I assume this is an AC motor. Don't the brush polarities reverse 60
> times per second already? Or possibly I'm not understanding what
> you're saying?
>
> Tom Veatch
> Wichita, KS
> USA
-MIKE- wrote:
> boyntonstu@gmail.com wrote:
>> Just wondering whether it could be done.
>
> I've always wondered the same thing.
Strange, I've spent my life NOT wondering :)
--
dadiOH
____________________________
dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico
On Jan 15, 7:06=A0am, "dadiOH" <dad...@invalid.com> wrote:
> -MIKE- wrote:
> > boynton...@gmail.com wrote:
> >> Just wondering whether it could be done.
>
> > I've always wondered the same thing.
>
> Strange, I've spent my life NOT wondering =A0:)
>
> --
>
> dadiOH
> ____________________________
>
> dadiOH's dandies v3.06...
> ...a help file of info about MP3s, recording from
> LP/cassette and tips & tricks on this and that.
> Get it athttp://mysite.verizon.net/xico
I find that question often interrupts dreams of a sexual nature.
It is just when the blond swedish twins start unbuttoning their tops
that
the question about motor reversal rears its ugly little head.
On Jan 20, 1:42=A0pm, Tom Veatch <n...@nada.org> wrote:
> ..."reversing polarity" of the brushes - which I interpret to mean
> switching leads - won't have any effect on rotation direction of a
> universal or any other type of AC motor. That would be no different
> than reversing the plug in the wall socket.
>
> On the other hand, breaking the motor open, and doing some internal
> rewiring might accomplish the mission.
What I intended was to swap the wires to the two brushes
(this is easy to describe, there are other rewirings that would
accomplish the same thing). Because the brushes activate
the ROTOR magnetization, the swap would reverse the rotor
poles without changing the other magnetic part, the STATOR.
That accomplishes the reversal of a brush-type (universal) motor.
Think of the (temporary N) pole on the rotor, pulled clockwise;
if you make it instead a (temporary S) pole, the attraction
becomes repulsion and the motor goes counterclockwise.
Swapping the wall socket polarity would reverse both rotor
and stator fields, so has no effect on rotation direction.
On Jan 22, 10:17=A0am, "Leon" <removespamlcb11...@swbell.net> wrote:
> "Leon" <removespamlcb11...@swbell.net> wrote in message
>
> news:TNHbl.18469$ZP4.6992@nlpi067.nbdc.sbc.com...
>
> > Yes, Turn the motor and blade unit 180 degrees so that the blade is
> > located on the opposite side.
>
> So uh, while my answer may have seemed like a wise ass answer, if you too=
k
> my suggestion would it accomplish what you are trying to do? =A0Having us=
e a
> RAS for 5 or 6 years to build probably half the furniture in my house and
> used lots of attachments on it, I have never needed to make the motor spi=
n
> in the opposite direction in which it was wired to do.
> Why do you need to reverse the spin on yours?
I have been experimenting with this:
http://www.youtube.com/watch?v=3DupDrKjY0adw
No shown are a few more items that we installed later:
A chip deflector and a scrub brush anti-kickback.
I am also working on a mechanical hold down.
Just having fun and games,
In article <blxbl.119121$9i5.58642@en-nntp-07.dc1.easynews.com>,
"Martin H. Eastburn" <lionslair@consolidated.net> wrote:
> boyntonstu@gmail.com wrote:
> > Just wondering whether it could be done.
>
> If it is 3 phase, swap two of the power wires.
>
> Otherwise the motor might have cw and ccw shades and
> it is a mater of re-wiring. Takes specs of that motor
> and knowledge.
At least a few radial arm saws (Wards Power Kraft for one) use/used
universal motors, wherein swapping the polarity of the rotor relative to
the stator ought to reverse the motor. One obvious way to do this on
such a motor is to swap the connections to the brush leads.
I do sincerely hope the original poster isn't intending to use the
radial saw in reverse; that sounds like a recipe for disaster. I
suppose if one wanted the blade on the opposite side of the traveler one
would need to reverse the rotation of the motor (and probably reengineer
the mount some), but otherwise...ouch.
--
Andrew Erickson
"He is no fool who gives what he cannot keep to gain that which he cannot
lose." -- Jim Elliot
In article <ntgcn4t77e8830cnjunpvjd47vjesvrk07@4ax.com>,
Tom Veatch <nope@nada.org> wrote:
> On Tue, 20 Jan 2009 15:24:09 -0500, Andrew Erickson
> <gmavt@drewe.reverse2mail.net> wrote:
>
> >They do indeed reverse 120 times per second (60 full cycles per second),
> >but so does the field coil, so the relative magnetic polarity of the one
> >with respect to the other stays the same. ...
>
> That's the way I understand it and I won't quibble on whether it's 60
> or 120 time/sec. Kinda depends on the definition of "reversing". So
> "reversing polarity" of the brushes - which I interpret to mean
> switching leads - won't have any effect on rotation direction of a
> universal or any other type of AC motor. That would be no different
> than reversing the plug in the wall socket.
>
> On the other hand, breaking the motor open, and doing some internal
> rewiring might accomplish the mission.
Switching the leads to the brushes generally does require breaking the
motor open and rewiring it internally a bit. It's not the same as
reversing the plug in the wall socket (which, as you correctly observe,
would have no effect on the direction of rotation). Swapping the input
leads changes both the field (stator) and the rotor, and so the rotation
stays the same. Swapping the brush leads changes only the rotor, but
leaves the field unchanged, so the relationship between them is reversed.
Here's the a link to a quick schematic sketch of this operation on a
series wound motor that might make things a bit clearer:
http://users.gmavt.net/drewe/pix/misc/Motor.png
--
Andrew Erickson
"He is no fool who gives what he cannot keep to gain that which he cannot
lose." -- Jim Elliot
In article <402cn4tto6sscu17j6rfkulhr2tgchosg0@4ax.com>,
Tom Veatch <nope@nada.org> wrote:
> On Mon, 19 Jan 2009 21:54:24 -0800 (PST), whit3rd <whit3rd@gmail.com>
> wrote:
>
> >Electrically reversing the motor is probably psosible
> >(usually these have brush-style motors, you could
> >reverse the brush polarities);
>
> I assume this is an AC motor. Don't the brush polarities reverse 60
> times per second already? Or possibly I'm not understanding what
> you're saying?
They do indeed reverse 120 times per second (60 full cycles per second),
but so does the field coil, so the relative magnetic polarity of the one
with respect to the other stays the same. In other words, the repulsion
or attraction of the two doesn't change. By swapping the brush
connections, the magnetic polarity of the rotor with respect to the
stator is reversed and the motor forced to turn in the other direction.
Motors of this design are often termed "universal motors" because they
will operate properly on AC or DC current, and furthermore are not
particular about AC power frequency. My RAS with such a motor is
specified as being for either 25Hz or 60Hz AC; I assume 50Hz would also
be OK. DC is presumably not listed because of the power switch being
insufficient to properly cut off high DC currents, not because the motor
would fail to work properly.
--
Andrew Erickson
"He is no fool who gives what he cannot keep to gain that which he cannot
lose." -- Jim Elliot
"Leon" <removespamlcb11211@swbell.net> wrote in message
news:TNHbl.18469$ZP4.6992@nlpi067.nbdc.sbc.com...
> Yes, Turn the motor and blade unit 180 degrees so that the blade is
> located on the opposite side.
>
So uh, while my answer may have seemed like a wise ass answer, if you took
my suggestion would it accomplish what you are trying to do? Having use a
RAS for 5 or 6 years to build probably half the furniture in my house and
used lots of attachments on it, I have never needed to make the motor spin
in the opposite direction in which it was wired to do.
Why do you need to reverse the spin on yours?
On Thu, 15 Jan 2009 09:36:07 -0600, Steve Turner
<bbqboyee@swtacobell.net> wrote:
>It's good that I've learned to set my coffee down before reading
>anything posted to this group. Out through the nose is no place to send
>a big slurp of hot coffee. :-)
Cleans and sterilizes the sinuses to prevent infection.
Tim Douglass
http://www.DouglassClan.com
"I'm not exactly burned out, but I'm a little bit scorched and there's some smoke damage."
On Wed, 14 Jan 2009 21:44:36 -0600, "Martin H. Eastburn"
<lionslair@consolidated.net> wrote:
>When I got my Delta Band saw - it came from a good dealer in
>a state. The manager was at a conference and the guys shipped
>a bandsaw and a motor. The motor had sawdust on it and wasn't
>in a new box. Hum - stripped it off something. Looks new.
>
>I installed it and the saw ran backwards. Just like a lathe....
>I swapped the wires as mentioned - inside it was marked - and
>then the saw cut wood. I then converted it to 14".
>
>So wood working motors as others reverse.
>
>Martin
>
>-MIKE- wrote:
>> boyntonstu@gmail.com wrote:
>>> Just wondering whether it could be done.
>>
>> I've always wondered the same thing.
>>
>>
Some do, some don't - and some are unpredictable. A good friend has a
nice radial arm saw from the 60's -can't remember the manufacture
(deWalt, perhaps?)r but it's hammertone green - and it will
occaisionally start backwards - but worse yet, if it jams it WILL
reverse. It will throw sticks with a veangeance given half a
chance!!!!!
On Thu, 22 Jan 2009 00:38:04 GMT, "Jay Giuliani"
<jrgiuliani@verizon.net> wrote:
>If it is a single phase motor it won't reverse.
>
>Think about all those two prong corded ac 115 VAC tools......
>
>You can reverse rotation on a three phase mpotor but as the other folks
>said, why?
>
>
>
>
>"Tom Veatch" <nope@nada.org> wrote in message
>news:402cn4tto6sscu17j6rfkulhr2tgchosg0@4ax.com...
>> On Mon, 19 Jan 2009 21:54:24 -0800 (PST), whit3rd <whit3rd@gmail.com>
>> wrote:
>>
>>>Electrically reversing the motor is probably psosible
>>>(usually these have brush-style motors, you could
>>>reverse the brush polarities);
>>
>> I assume this is an AC motor. Don't the brush polarities reverse 60
>> times per second already? Or possibly I'm not understanding what
>> you're saying?
>>
>> Tom Veatch
>> Wichita, KS
>> USA
You most certainly CAN reverse a single phase motor. On some motors
the connections are brought out to make it simple, on others you would
need to dig a bit.
My lathe has a 1 HP single phase cap start motor that can be started
in either direction.
Almost any single phase induction motor will run backwards if spun
fast enough backwards before power is applied
Robatoy wrote:
> On Jan 15, 7:06 am, "dadiOH" <dad...@invalid.com> wrote:
>> -MIKE- wrote:
>>> boynton...@gmail.com wrote:
>>>> Just wondering whether it could be done.
>>> I've always wondered the same thing.
>> Strange, I've spent my life NOT wondering :)
>>
>> --
>>
>> dadiOH
>> ____________________________
>>
>> dadiOH's dandies v3.06...
>> ...a help file of info about MP3s, recording from
>> LP/cassette and tips & tricks on this and that.
>> Get it athttp://mysite.verizon.net/xico
>
> I find that question often interrupts dreams of a sexual nature.
> It is just when the blond swedish twins start unbuttoning their tops
> that
> the question about motor reversal rears its ugly little head.
It's good that I've learned to set my coffee down before reading
anything posted to this group. Out through the nose is no place to send
a big slurp of hot coffee. :-)
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On Tue, 20 Jan 2009 15:24:09 -0500, Andrew Erickson
<gmavt@drewe.reverse2mail.net> wrote:
>They do indeed reverse 120 times per second (60 full cycles per second),
>but so does the field coil, so the relative magnetic polarity of the one
>with respect to the other stays the same. ...
That's the way I understand it and I won't quibble on whether it's 60
or 120 time/sec. Kinda depends on the definition of "reversing". So
"reversing polarity" of the brushes - which I interpret to mean
switching leads - won't have any effect on rotation direction of a
universal or any other type of AC motor. That would be no different
than reversing the plug in the wall socket.
On the other hand, breaking the motor open, and doing some internal
rewiring might accomplish the mission.
Tom Veatch
Wichita, KS
USA
Robatoy wrote:
> On Jan 15, 7:06 am, "dadiOH" <dad...@invalid.com> wrote:
>> -MIKE- wrote:
>>> boynton...@gmail.com wrote:
>>>> Just wondering whether it could be done.
>>
>>> I've always wondered the same thing.
>>
>> Strange, I've spent my life NOT wondering :)
>>
>> --
>>
>> dadiOH
>> ____________________________
>>
>> dadiOH's dandies v3.06...
>> ...a help file of info about MP3s, recording from
>> LP/cassette and tips & tricks on this and that.
>> Get it athttp://mysite.verizon.net/xico
>
> I find that question often interrupts dreams of a sexual nature.
> It is just when the blond swedish twins start unbuttoning their tops
> that
> the question about motor reversal rears its ugly little head.
I feel your pain in my waking state, other things when asleep :)
--
dadiOH
____________________________
dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico