5 Phase Stepper Motor

V

Thread Starter

Vikas Meshram

Hi everybody

I am designing 5-phase stepper motor driver. The coil configuration is delta. The problem I am facing is that I don't have information about the physical arrangement of the stepper motor
winding. Therefore motor don't run properly. Can anybody suggest how to determine the sequence.

There are ten wires on the stepper motor connector.

Thanks.

Vikas W. Meshram Scientific Officer, Laser Instrumentation,
Center For Advanced Technology, Indore- 452 013, MP,INDIA.
Email:[email protected]
 
W
Vikas,

The easiet way is to get the data from the manufacturer. But if you can't get the data from the manufacturer, hook up a dual trace scope to two adjacent windings and turn the shaft. You should be able to see the phases sequence as the motor generates electricity. You can get the whole sequence by advancing the scope leads each time to the next winding, until you have seen the
phase relationship among the five windings.

If you don't have a scope, try hooking up LEDs between the phases. This would be harder to figure out, but you should still be able to see the sequence. The best LEDs for this would be two-leaded bicolor; that way you can see the polarity reversal. This reversal happens even if the stepper can be driven in unipolar mode.

It is possible that the last method will not work if the stepper is not a permanent magnet type (variable reluctance). You should still be able to see it on a scope in this case as there is some residual magnetism left in the rotor which will generate a low magnitude sine wave. BTW, you can tell if it is a PM or VR type by shorting all the leads together and trying to turn the shaft. It the shaft is *much* more difficult to turn, then it is a PM type; if not, it is the VR
type.

If all else fails, you can simply take the motor apart and figure it out by carefully examining the stator windings and the rotor. Both full and half step sequences should be fairly easy to derive by inspection.

Have fun!

Willy Smith
Numatico SA
Costa Rica
 
J
Haven't done this for about 10 years, but if there is 10 wires, and 5 poles, and you know the proper voltage, try this:

1. Pick a wire at random. Apply voltage from this wire to another wire. Turn the shaft a bit and see if the rotor locks. Repeat this process until you identify all of the winding pairs.

2. to determine sequence, apply voltage to one pair, and get the rotor locked. Next, pick another set of wires and apply voltage. Watch which direction and how far the rotor turns. Play around with this to get the proper direction, Look for the minimum amount of shaft rotation between each step. Basically when you have the correct order, the shaft will turn the same direction and the same amount with each step. Just keep putting your test voltage
between pairs to determine this.

It would probably be easiest to rig up a small terminal strip and stand for the motor, unless you have 3 eyes and about a dozen hands to hold everything in place.


As an alternative, I guess you could check the motor case for a manufacturer and try to get a data sheet, but what fun would that be?

--Joe
 
L

Loren Schreiber

Opening a stepper motor will very likely destroy the flux within the PM core and is NOT recommended. Available torque will be reduced considerably, even if you can get it back together without iron filings and other junk
finding their way in as well.

>If all else fails, you can simply take the motor apart and figure it
>out by carefully examining the stator windings and the rotor. Both
>full and half step sequences should be fairly easy to derive by
>inspection.

Loren Schreiber
Systems Integrator, MCued
http://www.mcued.com/
 
M
At 07:54 PM 5/24/00 -0700, you wrote:
>Opening a stepper motor will very likely destroy the flux within the PM
>core and is NOT recommended. Available torque will be reduced considerably,
>even if you can get it back together without iron filings and other junk
>finding their way in as well.

You make a very important point. When I worked for Rapidsys/Computer Devices (late '70s) we always 'demagged' a motor before disassembling it. Motors were always assembled (and if necessary disassembled) in their demagnetized state. Given the close tolerances inside it is probably impossible to remove the rotor without
having it hit the stator, and as mentioned above, it will attract any ferrous junk in the area.

Mark
 
M

Michael Griffin

At 14:29 25/05/00 -0700, you wrote:
>At 07:54 PM 5/24/00 -0700, you wrote:
>Opening a stepper motor will very likely destroy the flux within the PM
>core and is NOT recommended. Available torque will be reduced considerably,
>even if you can get it back together without iron filings and other junk
>finding their way in as well.
<clip>
De-magging depends upon the type of magnets used. Alnico magnets are prone to this. I don't recall if rare earth magnets are. Normal inexpensive ceramic magnets (used in many low cost motors) do not have this problem. If you are not sure, then don't open up the motor.
This problem is not just with stepper motors. Any permanent magnet motor (or other permanent magnet machine) is subject to this, depending upon the type of magnets used. In addition to dissassembly, extreme over current
(i.e. very high flux generated by the windings) or heat can also de-mag a motor, although this generally happens to a lesser degree.
Some manufacturers charge the assembly containing the magnets separately from the rest of the motor as there are certain minor advantages
to be gained in aligning the flux correctly. However, they have special assembly tooling for this.


**********************
Michael Griffin
London, Ont. Canada
[email protected]
**********************
 
E

eddy current

Personally I would make life easy on myself......get yourself a stepper motor that you can get the technical information.

Any questions regarding nuclear, aerodynamics, displays etc please feel free not to email me....


thanks and goodbye............







> Hi everybody

I am designing 5-phase stepper motor driver. The coil configuration is delta. The problem I am facing is that I don't have information about the physical arrangement of the stepper motor
winding. Therefore motor don't run properly. Can anybody suggest how to determine the sequence.

There are ten wires on the stepper motor connector.

Thanks.

Vikas W. Meshram Scientific Officer, Laser Instrumentation,
Center For Advanced Technology, Indore- 452 013, MP,INDIA.
Email:[email protected]
 
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