# Motor voltage range?

I am pretty new to all this stuff so this is probably a rookie question, but if a DC motor is a "5V motor", can you connect it to a higher voltage or will it damage the motor? I've seen some motor specs that give a range of voltages and some that just say 5V or 12V motor. Can I connect a 5V motor to a 12V power supply? What are the repercussions?

ianmurphy:
I am pretty new to all this stuff so this is probably a rookie question, but if a DC motor is a "5V motor", can you connect it to a higher voltage or will it damage the motor? I've seen some motor specs that give a range of voltages and some that just say 5V or 12V motor. Can I connect a 5V motor to a 12V power supply? What are the repercussions?

Within reason, heat is the only thing to damage motors. So, sure, you can connect a 5 volt motor to 12 volts, but only for a few seconds and then you have to let it rest until the internals cool.

Paul

Brushed DC motor voltage rating is generally considered to be the recommended maximum for long term, continuous operation.

Exceeding the rated voltage will shorten the motor's life, especially the brushes.

And just in case you don't already understand this...doubling the voltage to a motor will cause it to try to turn twice as fast as normal and use much more current than usual. So overheating, damage to brushes and commutator, extra sparking causing interference and damage to the bearings/bushings.

On DC brushed motors you can usually exceed the nominal voltage by 50% or 60% relatively safely if you are only running the motor for relatively short times. Back in the day when we flew RC planes on brushed motors it was normal to run 6V motors on about 10V but only for 3-4 minute flights. Even then the motors wouldn't last all that long.

Steve

Paul_KD7HB:
Within reason, heat is the only thing to damage motors.

Well actually its not that simple. Overspeeding the bearings will accelerate wear and eventually destroy them, and overspeed the rotor and it might explode (this is very extreme, but it can happen and is a particular hazard for unloaded series-wound DC motors). Normally the windings come adrift and jam in the gap before a rotor explodes, but you wouldn't rely on that!

Most small motors have brushes and brush-springs that will fail from arcing and over-current before the armature completely cooks (after all the faster a motor spins the better it air-cools itself).

Basically you can expect a small motor to likely survive 2x voltage but wear out much much faster. Larger motors can be closer to the thermal limit and often have thermal cutout-switches embedded in the field windings (if they have field windings).

Small brushed motors wear out fast enough as it is though, I'd not exacerbate that.