Author Topic: Checking stepper motors.  (Read 7752 times)

Offline waggle

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Checking stepper motors.
« on: March 18, 2012, 06:58:08 AM »
Hi guys,

A few years ago I acquired a couple of smallish stepper motors. I am now having a bit of a clear-out and dont know wether to throw them out or not.
I do not know if they work or not, and I dont even know how to test them.
Is there a cheap (free) way of finding if they are worth keeping?

Cheers
Tony

Offline Bluechip

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Re: Checking stepper motors.
« Reply #1 on: March 18, 2012, 07:35:46 AM »
Depends what they are  :scratch:

Any part numbers?

How many wires?

Any Pics.?

What are they out of ?
If they have been ripped out of some obscure machine, it's possible they are not steppers but Brushless DC motors.


BC
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Offline John Rudd

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Re: Checking stepper motors.
« Reply #2 on: March 18, 2012, 07:45:32 AM »
If you have a multimeter (dvm) you could test the windings for equal resistance and you could hand crank the spindle and measure the voltage from the windings....Ultimately a stepper driver would be best..
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Offline John Stevenson

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Re: Checking stepper motors.
« Reply #3 on: March 18, 2012, 08:21:04 AM »
If they are identical wire them together colour to colour and spin one, the other should turn identically.

John S.
John Stevenson

Offline David Jupp

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Re: Checking stepper motors.
« Reply #4 on: March 18, 2012, 08:40:23 AM »
Mechanically you should be able to check for play / roughness in the bearings - just turn / wobble by hand. 

Offline waggle

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Re: Checking stepper motors.
« Reply #5 on: March 18, 2012, 10:39:16 AM »
I am not able to turn the shafts, not sure if this means they are seized or if they should be like this. I know they were working when they were removed from their old home.
The wires are :

1st motor: 2 blacks and earth
2nd motor: brown/blue/earth

The markings are;

escap   34
L 11 219 E 5

also

(EX) sd l G3
PTB nr lll
B/E -27  909
24VDC

Hope this means something to someone.

I will sort out some pictures for later

Cheers
Tony

Offline Bluechip

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Re: Checking stepper motors.
« Reply #6 on: March 18, 2012, 11:46:05 AM »
Neither seem to be steppers, just maybe DC motors .. ???

AFAIK the minimum number of wires to a stepper is 4, ie bipolar connected.

'escap' ??

Portescap ??

http://www.portescap.com/category-brush-dc.html

Their stuff is very good and very expensive IIRC .. not your usual junk.

Cannot find anything in the search box with the numbers you gave.

Both motors should turn by hand, unless there is a reduction gearbox attached  to them, in which case you may have problems in the gearbox, or more likely, a high reduction ratio. If, in fact, you are turning a g/box output shaft, you may be trying to spin the motor itself at a high rate of knots.

They don't by any chance vaguely resemble this motor ?? ie an ally blob on the end ??

http://cpc.farnell.com/mfa/940d1001/motor-gear-4-5-15v-100-1/dp/HK00908

BC
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline waggle

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Re: Checking stepper motors.
« Reply #7 on: March 18, 2012, 12:41:01 PM »
Ok, I will try and sort out a 24 volt supply and give them a go.

They are definately Escap as I have found something similar on Ebay.

In their original role they were very slow turning ( maybe 10-20 rpm ) so the shaft problem may well be down to gearing.

Thanks

Tony

Offline Bluechip

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Re: Checking stepper motors.
« Reply #8 on: March 18, 2012, 12:44:46 PM »
Tony

Does not have to be 24V.

12V Car Battery will ekkle the things, or should do  :thumbup:

BC
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Offline waggle

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Re: Checking stepper motors.
« Reply #9 on: March 18, 2012, 12:50:39 PM »
Thanks Bluechip.

I'll give it a go.

Offline waggle

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Re: Checking stepper motors.
« Reply #10 on: March 18, 2012, 12:59:48 PM »
It seems that they are indeed DC motors.

The first one works well, around 10-20 rpm as expected.

Sadly the other one just buzzes. I will have to strip off the gear box and see if it is the motor or the gearbox that is at fault.

Thanks guys

Your help has been invaluable.

Tony

Offline Bluechip

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Re: Checking stepper motors.
« Reply #11 on: March 18, 2012, 04:00:15 PM »
Tony

If it buzzes a bit, check the brushes are free to move.

Alternatively, use it as an audible warning device  :)

BC
I have a few modest talents. Knowing what I'm doing isn't one of them.