I'm looking for help on how to troubleshoot two DC motors.
I have Arduino Uno R3 with accompanying Motor Shield, also R3. I use the shield to run two DC motors. Motors are just no-name motors with nominal (sticker) characteristics:
- M1: 12V, 3W
- M2: 12 V, 5W
I'm using 9V power supply for Arduino. I read 8.67V on Vin/Gnd connectors, which seems fine.
When I run the motors I'm getting the following readings using a multimeter:
- M1: 6.76, 310mA
- M2: 6.9V, 160mA
The voltage makes sense to me, but the currents don't. I can always assume that the stickers are incorrect but I'd like to know if there is anything I can do with my multimeter to troubleshoot if one of the motors is faulty somehow.
I took the measurements with both motors connected to connectors A and B, and with the other motor disconnected but the readings were the same. I assume they don't affect each other or Arduino. Motor Shield data sheet says connectors A and B can supply 2A each, so I also assume the motors are not causing that kind of trouble.
The reason to investigate this is because motors are to operate 24/7, cycling (i.e. with rest intervals nearly equal in length to run intervals, say 40s run, 35s rest). However, they often stop working for apparently no reason, sometime after a day, sometimes after a week. Connecting them to benchtop DC power supply will make them run again. I will leave them off for a day or so and the next they they will run again. And so on. I double-checked my Arduino code elsewhere on the forum and the code is fine. Also, motors are not to run 28 days or more, so I never run out of bytes in my float variables.
Please let me know if I can add any information. I'd appreciate any advice.