Test the MCOR reading at the Controller

[InVision]

Scotty thanks again. I really do appreciate your help.

Are there aftermarket MCORs?

Thx

[jakesnake27]

Originally Posted by InVision

Are there aftermarket MCORs?

I don't think so...

[DaveMJ]

Sorry for reviving an old thread, but the topic was spot on.

Vehicle is a 2004 Carryall 48 volt Series cart with original PowerDrive system components, including a 300 Amp Curtis controller. I just put in an upgraded motor and I'm definitely seeing an improvement in performance. I wanted to make sure I was getting a full throttle signal to the controller, to make sure I am squeezing everything I can out of the system.

I pulled the green and yellow wires to the controller and got the following readings:

No throttle - 8640 ohms
MCOR micro switch operation - 8140 ohms
Full throttle - 1267 ohms

Numbers are all higher than stated in a previous post in this thread - "MCOR readings should be 1100 ohms at the floor and around 6800-7000 at zero throttle".

Full throttle value is 167 ohms high, about 15% above the 1100 ohms. Does that mean my cart is running at approx 85% of full throttle?

I have already added a tie wrap to the throttle pedal where it interacts with the MCOR shaft to ensure I have no lost motion.

There is an Alltrax 500 in my near future. I believe I should be able to calibrate throttle input to get back to 100%. Should I be thinking about replacing the MCOR?

[Sergio]

The actual resistances do not mean much since the throttle signal is voltage based.

To properly check the MCOR signal you need to measure the voltage on the wiper wire, yellow wire on terminal #3 in your case.

Measure the voltage with the wire still connected to the terminal, the voltage needs to be above 4.65v for the controller to detect full throttle.

[DaveMJ]

Is that 4.65 volts relative to B- or the Green wire?

[Sergio]

Originally Posted by djohns18

Is that 4.65 volts relative to B- or the Green wire?

Unless otherwise noted, any voltage reading is in reference to Controller B- or pack negative

Also, that voltage is for the FNR in Forward, when the FNR is on Reverse the maximum voltage is less that 3.0v in order to reduce the max speed.

[DaveMJ]

Okay - I get 7.8 volts, does that even make sense?

I measured it two ways and got the same result. In forward with the green (A1) motor cable disconnected. Then with motor connected in neutral with the front micro switch (#1) manually actuated.

[Sergio]

Was the yellow wire still making connection with the terminal on the controller?

Did the voltage start near 0.3v when the pedal was up?

If not make sure the purple wire from the MCOR is connected to B-.

[DaveMJ]

To answer your questions:

Yes - yellow was making contact with the controller terminal - cart was running fine. It was a little loose so I squeezed it a little with some needle nose pliers to make it tighter- no change in readings.

Voltage started at Zero, was about 0.6 volts when the solenoid activated and 7.8 volts at full throttle.

Yes - I can see the purple wire connected to the B- stud. I get continuity between the terminal on the purple wire and B-, so unless I have a bad crimp or a wire/connector issue the MCOR should be getting B-. Guess I can pull the connector and check.

[DaveMJ]

So I pulled the MCOR connector, purple wire has continuity to B-.

Not sure what is most relevant, so I measured everything:

Purple to Black = 7.37 k ohms at zero throttle (not measured at full throttle as it is constant).
Yellow to Black = 8.6 k ohms at zero throttle, 1.26 k ohms at full throttle.
Yellow to Purple = 1.32 k ohms at zero throttle, 8.6 k ohms at full throttle.

I believe yellow to black equates to controller 2 and 3. So these readings are consistent with my previous resistance readings at the controller.