Unipolar stepper motor additional part. What is this?

Thread Starter

crazybuoy

Joined Sep 19, 2010
77
I have a Unipolar stepper motor with attached an additional coil as show in following two images. It takes high mechanical force, while moving motor's shaft with hand. And after removing this additional part by removing four screws, then it takes just a little mechanical force to move the shaft with hand.

Please guide me what is this attached additionally, how to use it and what is its benefit?
 

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jpanhalt

Joined Jan 18, 2008
8,321
Very likely an electromechanical clutch or brake. If you add voltage to the extra coil, is the shaft easier to turn?

The advantage is to provide a brake for the motor.

John
 

MaxHeadRoom

Joined Jul 18, 2013
19,409
+1 on a brake, but one section should be attached to the shaft and rotate normally while the other remains stationary, does the rear disc revolve with the shaft?
Max.
 

AlbertHall

Joined Jun 4, 2014
8,774
+1 on a brake, but one section should be attached to the shaft and rotate normally while the other remains stationary, does the rear disc revolve with the shaft?
Max.
If the motor has a shaft at the other end (can't see in the pictures) then the moving part of the brake could be completely enclosed in that casing.
 

Thread Starter

crazybuoy

Joined Sep 19, 2010
77
Very likely an electromechanical clutch or brake. If you add voltage to the extra coil, is the shaft easier to turn?
I also think so, but not sure, I did not attach this motor to driver yet. If I do, then five motor wires will go to driver, then how should I use two wires of so-called clutch or brake. I also checked it by opening it, there was not any gear inside.

+1 on a brake, but one section should be attached to the shaft and rotate normally while the other remains stationary, does the rear disc revolve with the shaft?
At rear, it has two disks like (disk+separator+disk), and last rear disk revolves with shaft. How should I apply voltage to this additional part while attaching this motor to driver?

If the motor has a shaft at the other end (can't see in the pictures)
I am sending further two images, motor has shaft both sides, plz check images.

I have several steppers that were attached to precision valves that also had optical encoders on them too.
Please send the clear images of those motor having optical encoder.
 

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MaxHeadRoom

Joined Jul 18, 2013
19,409
A typical brake voltage would be 24vdc, what is the resistance across the two leads?
It does not appear to be an encoder.
If it is a brake, it should be energized as soon as a command is given to the motor.
Max..
 

jpanhalt

Joined Jan 18, 2008
8,321
For what voltage is your motor rated? If it is low-voltage, I might try 12 V on the brake first, perhaps with an in-line resistor or DC light bulb too just to be conservative.

John
 

Thread Starter

crazybuoy

Joined Sep 19, 2010
77
The sticker on Break says "24v,7w". Any how, I don't want to use break, I just bought this motor with this additional component. I have separated it from motor.
 
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