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Burned out 24v23 CS drivers

Hi,

I’m using two 24v23 CS drivers with two wheelchair motors. I’ve managed to burn out two of the drivers - I ordered 4 in total to be safe and I’d like some advice to avoid burning my last 2 out. I’m using 2 Arduinos connected via GND and TX RX to generate PWMs for each of the drivers. Each Arduino is powered by its own 9v battery.

I’m having a hard time determining how I managed to burn out 2 drivers on separate occasions - my motors are hoisted in the air, so there is very little load right now. For each motor/ driver, I have the following setup:

  • 1 wheelchair motor
  • 2 12V7AH batteries connected in series (24v total per driver) each with a 30A automobile fuse connected inline on the positive terminal of the batteries
  • 1 Arduino with pins connected to the Driver GND, DIR (HIGH or LOW), PWML (HIGH) and PWMH (PWM signal)

Since there is very little load on the motors - they’re off the ground for testing - the current draw remains low, they haven’t stalled and I haven’t felt any heat on the drivers.

I wrote a script to ease changing direction: It goes from the current speed to 0 in 5 steps with 100ms per step.
For example, to go from a speed of 255 to -255 it does the following:
255 at 0ms
204 at 100ms
153 at 200ms
102 at 300ms
51 at 400ms
0 at 500ms
Change direction pin and set new speed at 255

My suspicion is that maybe going from 0 to full speed is the culprit - is that possible?

Could it be noise that burned the drivers out? I haven’t added bypass capacitors to the motors yet - would that help avoid a burnout?

Is it smarter (more useful) to have my between the driver and motor instead of battery and motor?

Are there other steps I can take to protect my Drivers?

Hello.

It is possible that driving the motor from stopped to full speed damaged the driver. You might try implementing some sort of acceleration limiting to limit the inrush current. I am not sure if noise damaged the driver. If you have access to an oscilloscope, you might try measuring the noise on the signal and power lines of the driver. Also, it is unclear what you are asking by “Is it smarter (more useful) to have my between the driver and motor instead of battery and motor?”. Could you clarify your question?

If you tell us more about you setup, I might be able to let you know if I see any other issues or precautions you could take. What are the specifications of the motor? Could you provide a link to the datasheet? Could you post photos of your setup?

- Jeremy

I Jeremy.

I need to add some “easing” on the acceleration anyway - I’m going to get whiplash the way it moves now. :slight_smile: Once that’s done, it should limit any drastic changes in speed.

My question was because it occurred to me that positioning the fuse between the driver and the battery doesn’t necessarily protect the driver from any overcurrent as well as positioning the fuse between the driver and motor - if there is any kind of kickback from the motor, I imagine that would make the most sense.

I’ll see if I can get a photo of my setup. Thanks for your response.

I bought the motor from what I would consider to be a reputable wheelchair distributor/ repair center, but my motor is unlabelled. Unfortunately, I’m not positive of it’s specifications.

The location of the fuse will depend on what you are trying to protect. Placing it between the battery and motor driver will prevent you from drawing too much current from the battery. Placing it between the motor driver and motor will prevent the motor from drawing too much current. Also, if you have it in between your motor driver and motor, your system can stay on after the fuse blows, and you can detect the blown fuse by seeing the motor current go to zero.

- Jeremy

A post was merged into an existing topic: Possible to recover from over-current short-circuit?