Thanks everyone for the information. I can tell by the questions that
I didn't provide enough information, and I have OK - I want to be extra
clear.

A. My Stubby lathe has a 3-phase motor on a controller that allows me
to switch the motor direction while the lathe is spinning. the
controller, I presume brakes the rotation down to zero rpm, and then
starts rotation in the opposite direction. I do not stop the spinning
before switching directions. Once in a great while the braking torque
does cause a chuck to unscrew, but I generally tighten the chuck so
this does not happen. The slow down and speed up are rather gradual.
there is no "hard slam" reversing going on. So, this is my experience
with reversing on a lathe.

B. The motor for my mini lathe is a single phase 110 motor that has
wiring to allow rotation in both directions. I will not have a
controller. It will be wired directly to 110 AC through whatever
switch(es) I install.

So, based upon all the great responses, here are my more precise
questions:

1. If I flip the polarity on the switch to instantly reverse motor
direction, does the motor gradually slow down, then gradually speed up
in the other direction, or does the motor attempt to slam direction
changes? In other words, to avoid slamming direction change, I must
allow the rotation to stop before re-energizing the motor in the
opposite direction?

2. If I flip the polarity on the switch to instantly reverse motor
direction, does this damage the motor? In other words, to avoid motor
damage, I must allow the rotation to stop before re-energizing the
motor in the opposite direction?

Assuming the slamming effect is what happens and/or that motor damage
happens, then I will use some sort of three position set-up where I
turn off rotation in one direction. Wait until the rotation stops,
then re-energize the motor for reverse rotation.

Thanks again.
Joe Fleming



Darrell Feltmate wrote:
Joe
When I put a reversing switch on a motor I use one that has a "dead"
position in the center so that I can not forget to turn the motor off before
changing direction. On the other hand I am a devote coward who hates pain to
himself or the lathe :-)

--
God bless and safe turning
Darrell Feltmate
Truro, NS Canada
www.aroundthewoods.com

"Joe Fleming" wrote in message
ups.com...
All,

I am adding a motor to a mini lathe and have a wiring question. The
motor I have is reversible. I can add a switch to the circuit to
switch polarity and change rotation direction. Here is the question:

Can I switch the motor from forward to backward when the motor is
already turning? Or do I need to cut power and stop the rotation
first, before switching direction and reapplying power?

Thanks,
Joe Fleming - San Diego