# How much can I overvolt a brushless motor?

I know that motor speed depends on applied voltage, both for DC and brushless motors: I applied 12V to a 6V motor and it started running very fast... until it burnt! :-)

Questions are actually two:

1. how much voltage can I apply over the rated voltage without damaging the motor?
2. why?

About question 2: I think it depends on maximum heat the windings can dissipate, which depends on current flowing into them... but then I got lost: power dissipated in a winding is I^2 * R, but how much is I? Is it V/R? But I tried plotting the following formula and it results in absurd values...

Power dissipated in motor:

• $P_1 = \frac {V_1^2}R$ (nominal condition)
• $P_2 = \frac{(V_1 + V_2)^2}R$ (overvolting)

This results in:

$P_2 = P_1 + \frac{2*V_1V_2 + V_2^2}R$

But this gives impossibile results...

• Asking for "applying voltage" probably means to the circuitry that drives the motor, which will have an absolute max rating in its datasheet, beyond which all bets are of. Jul 11, 2016 at 21:52