CIM no-load current vs applied voltage

[Ether]

Originally Posted by Ether

[Globe has published an interesting primer on DC motors which addresses this topic

Check out page 5 of this presentation.

FRC 2005 KoP FP motor free current vs volts. Linear with y-intersept (similar to Globe's doc).

[kamocat]

Wow, that's the first real data on an FRC motor I've seen.
However, there's a lot of detail missing:
Are the different data points different motors, or is it all the same motor?
What was the power supply? What was used to control the voltage?
Is this with the gearbox or without?
How fast did it turn?

[Ether]

Originally Posted by kamocat

Wow, that's the first real data on an FRC motor I've seen.
However, there's a lot of detail missing:
Are the different data points different motors, or is it all the same motor?
What was the power supply? What was used to control the voltage?
Is this with the gearbox or without?
How fast did it turn?

Are the different data points different motors, or is it all the same motor?

At first I thought it was one motor with a lot of noise in the data, but now you have me wondering.

What was the power supply? What was used to control the voltage?

It was probably a variable DC supply.

Is this with the gearbox or without?

Did the FP come assembled with a gearbox in the 2005 KoP? If yes, then with; else without... would be my guess

How fast did it turn?

Yes, I would have liked to see that as well, to do a sanity check with the equations.

[kamocat]

Do you know if a variable-voltage DC supply is usually made with a movable-core transformer, or with PWM?
If it's done correctly, it shouldn't make a difference. I was mainly worried that they were using a Victor 884 or 883. I know those have very poor control at low duty cycles.