For a device I am creating, I need to supply up to four (4) mini DC motors from a single battery. The operating potential and current will be 3V-6V and 150mA.
I assume the motors will need to be wired in parallel. My question is, how would I split the current from a single source to power each individual motor. Also, is there a way to limit the current to each motor so that it operates under the ideal current. I.E., I want to deliver no more than the 150mA to the motor.
Hi,
The best way to control the total current the motor uses is by limiting the amount of torque it needs to produce.
A simple way current is normally limited to a load is by adding a current limiting resistor in series. Of course, you need to get a resistor for the right amount of current. In your case, a typical resistor would not be enough (1/4 Watts), since 6 V x 150 mA =~ 0.9 W. The two simplest options would be to either use a 1 Watt resistor (of the right amount of Ohms) or 4 resistors of 1/4 Watts that have 4 times the resistance (Ohms) and place them in parallel.
Since 150 mA @ 6 V DC would mean a load / resistance of roughly 40 Ohm (R = V/I), you would could use 4 resistors of ~160 Ohm in parallel, that circuit being in series between your power source and your motor (1 of these “current limiting” circuit per motor). Please note that this would cap the current to at most 150 mA @ 6 V DC. If the voltage used is different, since this current limiting circuit is entirely passive, you would need to change the resistance value, too.
We hope this helps!
Sincerely,
