Hi Group:
I bought a surplus GE motor with a PWM (Pulse Width Modulation)
printed board. The board now causes the motor to vibrate and run
rough, particularly noticable at low speed on my lathe.

I've been able to prove the board is at fault, by trying a different
board temporarily.

Does any one have a spare board or know where to acquire one?

Joe Yablonski

-- Remove par from email address for replying

On Mon, 10 Jan 2005 20:26:21 GMT, golf wrote:

I bought a surplus GE motor with a PWM (Pulse Width Modulation)
printed board. The board now causes the motor to vibrate and run
rough, particularly noticable at low speed on my lathe.

Try getting it repaired (probably not by GE). The usual failure mode
is one of the output MOSFETs in the bridge circuit, which keeps the
motor "running" but gives the vibration you describe. It's not a hard
fault to detect, nor to repair - any reasonable electronics person
should be able to sort it.

On Mon, 10 Jan 2005 15:13:49 -0700, Andy Dingley wrote
(in article ):

On Mon, 10 Jan 2005 20:26:21 GMT, golf wrote:

I bought a surplus GE motor with a PWM (Pulse Width Modulation)
printed board. The board now causes the motor to vibrate and run
rough, particularly noticable at low speed on my lathe.

Try getting it repaired (probably not by GE). The usual failure mode
is one of the output MOSFETs in the bridge circuit, which keeps the
motor "running" but gives the vibration you describe. It's not a hard
fault to detect, nor to repair - any reasonable electronics person
should be able to sort it.


Yep, the MOSFET (and freewheel diode) plus any electrolytics.

-Bruce