Is it possible to reverse the rotation of a radial saw motor?

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Just wondering whether it could be done.
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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.
Martin
snipped-for-privacy@gmail.com wrote:

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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.
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Andrew Erickson wrote:

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.
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snipped-for-privacy@gmail.com wrote:

I've always wondered the same thing.
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-MIKE-

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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:

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On Wed, 14 Jan 2009 21:44:36 -0600, "Martin H. Eastburn"

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!!!!!
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-MIKE- wrote:

Strange, I've spent my life NOT wondering :)
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dadiOH
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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.
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Robatoy 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. :-)
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On Thu, 15 Jan 2009 09:36:07 -0600, Steve Turner

Cleans and sterilizes the sinuses to prevent infection.
Tim Douglass
http://www.DouglassClan.com
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Robatoy wrote:

I feel your pain in my waking state, other things when asleep :)
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On 1/15/2009 8:07 AM Robatoy mumbled something about the following:

Shredded wheat and milk through the nose is painful. Oh, and you owe me a keyboard.
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Don't believe so.
It is an AC motor and will rotate with the field.
If it was three phase it could be done.
Why??
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Yes, Turn the motor and blade unit 180 degrees so that the blade is located on the opposite side.
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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?
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I have been experimenting with this:

http://www.youtube.com/watch?v=upDrKjY0adw

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,
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On Jan 14, 5:13pm, snipped-for-privacy@gmail.com wrote:

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.
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wrote:

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
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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.
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