# battery

how can i determine how much max current can my dc motor draw?

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Power your motor by connecting some power supply across it. Then use your multimeter to take the current readings by connecting it to the contacts of the motor.

I'm not sure though. It was suggested to me by someone and I suggest it forward to you. Never tried it before.

...that's just free running current, which is minimum current.

Max current is when the motor is stalled. The good news is that you can calculate the max current without actually having to power the motor and hold it in place, which might damage it permanently.

When the motor is stalled the current is determined solely by the resistance of one motor winding and the supply voltage. So, for a brushed dc motor, take your Ohm meter and simply measure the resistance accross the motor leads, you may want to spin the motor around very very slowly by hand until you get a minimal resistance reading. Write down the minimum resistance measured. To determine the maximum current divide the supply voltage by the winding resistance. Let's say you measure 10 Ohms and you have a 12 Volt battery, the maximum current through your motor will be 1.2 Amps

Great..thanks man..i think i read somewhere-Stalled means the power to stop the motor at its top speed.

is there a huge difference between the stalled one and the method described by basile and vishu?

thanks for the reply..all of you

thanks..any suggestion about how much current should i give for input o measure the max current.without damaging the motor?