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Author Topic: Tuirning Stepper motors by hand  (Read 5477 times)

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Offline berty

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Tuirning Stepper motors by hand
« on: July 30, 2016, 07:43:34 AM »
Hi to all
Can turning stepper motors by hand when power is swictched off destroy the electrics.

 I did a short cut turning the stepper handles.with the power off,,, a few monrths later went to use it again under power to find it would not work,,,I noticed that the LED on the driver board lit up when I turned the steppers,, could this have blown the driver board up..The steppers used to buzz when on, now buz then go silent..
In my haste to get the machine working again I purchased a repalcment 3 axis driver, but cant help wondering if I should not turn them by hand,, but have seen loads on the net with handles.
Berty

Offline Tweakie.CNC

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Re: Tuirning Stepper motors by hand
« Reply #1 on: July 30, 2016, 07:51:47 AM »
Quote
Can turning stepper motors by hand when power is swictched off destroy the electrics.

Yes it can.

Some stepper motor drivers do incorporate protection against the back emf but if turning by hand it is advisable to only rotate the motors slowly.

Tweakie.
PEACE

Offline berty

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Re: Tuirning Stepper motors by hand
« Reply #2 on: July 30, 2016, 07:57:15 AM »
Cheers Tweakie,
That will be what I have done then.
So what is the point of the handles, is there a mod to make them safe to use.

Thay all have plugs on them would it be safe to use them unpluged,
Berty

Offline Tweakie.CNC

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Re: Tuirning Stepper motors by hand
« Reply #3 on: July 30, 2016, 08:18:13 AM »
I think this is perhaps bit of a grey area.

I have a hand-wheel on my Y axis and I often (leaving everything switched on) disable the Y axis then move the table by rotating the hand-wheel until I reach the desired position then enable the Y axis to continue the work. This has never caused me any electrical problems.

On the other side of the coin I was running some stepper motor tests to find the highest speed available and stalled a motor (which had overrun because it was driving a small flywheel) at 4,500 rpm which completely destroyed the driver electrics.

If you are going to unplug the motors which would be safe then - switch off the controller electrics and wait a couple of minutes (give the caps time to discharge) before actually pulling the plugs.  ;)

Tweakie.
« Last Edit: July 30, 2016, 08:21:24 AM by Tweakie.CNC »
PEACE