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Measuring Current of 24v dc motor

how to measure the max current of 24v dc motor.. please give me step by step guidance.
many thanks

steveastrouk5 years ago
Tricky, Any decent motor is likely to pull enough short circuit current to a.) burn out your meter and b.) burn out the motor.

You need to get an idea of the maximum power the motor can DELIVER. Does it have any rating plate ?
Libahunt5 years ago
If you have a power source for it and it can be turned on, then you may be able to measure with multimeter. Usually they are able to measure up to 10 amps DC. To find out, if your motor might be in that range - measure the resistance and do some Ohms law calculation.

Current consumption is different while turning fullspeed with no load and when stalled (motor can't turn because of too heavy load). Try to measure both, as the stall current is the biggest possible - depending on the usage, can be important to know. Stall current might come close to what you will calculate from the resistance.

You are doing it at your own risk - your bones and your electronics. I have not seen how big and powerful the motor looks, I can't make sure you connect, calculate etc do everything right and stay in safe range. The steps I wrote about are what I would do with a motor of a size I would not be scared of and with a multimeter I have right to burn down. I am not responsible of damage that may happen.

1. Read the multimeters user manual first!

2. Measure the resistance of motor coils - probably it has two wires, so just between them. Then calculate: 24V / x ohms = y amps.
(Pay attention to multiplyer prefixes like kilo-ohm - it means *1000 ohms, milli-ohm means 0.001 ohms etc.)

3. Are the calculated amps less than 10 or what the multimeter is meant for?

4. If yes, then do the steps mentioned in manual to measure current (might involve plugging a probe to other socket and turning the knob) and connect the multimeter in series with one of the wires and turn the motor on. Now you should have running current reading.

5. Turn the motor off, then find a way to keep the shaft still and be careful that the whole thing does not fly into your face or break your fingers - it has to be fixed in place safely. Then turn motor on again to measure stall current.
Thermionic5 years ago
Max current comes from the manufacterers tests and data sheet, or you testing it yourself.
Jayefuu5 years ago
Does it have a label on it? Manufacturer? If so the easiest way is to Google the make and model and find the manufacturer's data sheet for it.