DC Motor Winding Temperature Measurement 1

[Roderick Harvey]

Hello,

I am trying to measure the temperature rise on a 12Vdc motor windings. I have tried using the resistance method measuring at the positive and negative motor connections, but the issue I am having is, if the commutator is not in the exact position as when the initial measurements are taken and when the final measurements are taken at the end of the test, the temperature rise calculation will be incorrect. Does anyone have a solution for taking this measurement? Thank you

 

[waross]

The non-linear voltage drop across the brush/commutator interface will frustrate accurate resistance measurements.
No guarantee but try removing the brushes and contacting the commutator directly with solid copper wires as probes.
Do some measurements as you slowly rotate to armature to check that the windings are balanced.
You will probably be able to see the effect when the wire probe bridges two commutator segments.
Use this effect to make sure that your measurements are not taken with the probe bridging segments.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[edison123]

Number the segments (1,2,3, xx) with a marker.

Use a DLRO to measure the resistance across a pair of segments (1 to 2, 2 to 3, 3 to 4, etc) with all the brushes removed before and after the full load run. De-energize the motor when you do this.

Muthu

http://www.edison.co.in

 

[waross]

A 12 Volt motor may not have an exposed commutator. That is why I suggested removing the brushes and probing through the brush holder holes.
If the commutator is exposed then by all means use Edison123's method.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Roderick Harvey]

Thank you for the advice, I will give them a try.