# DC/AC motor stall current

To clarify beforehand: Under DC motor I understand a motor with 2 terminals where you apply DC voltage to get current flowing in 1 direction(some people use DC to describe 3-phase brushless motors) With AC motors I understand n-phase brushless motors with n amount of terminals where you apply a AC voltage in different phases on the different pairs of terminals.

I also know for a fact that mechanical resistance is proportional to electrical resistance so it's gets even more confusing knowing this.

Now for the actual question: I know that a type of motor can get damaged if stalled. I've also read that current is minimal when a certain other type of motor is stalled. Can I get a explanation which one is which and why?

• "I also know for a fact that mechanical resistance is proportional to electrical resistance " Wrong. Electrical resistance is simply a property of the circuit (wire, brushes, leads, terminals). Mechanical resistance is to do with bearing construction (how easy it turns). If you actually mean torque this is a function of current. Current depends upon conductance (the inverse of resistance), the speed of rotation (back emf) and the applied voltage. – JIm Dearden Oct 25 '16 at 12:04
• Jim, in the asynchronous AC motor equivalent circuit, mechanical resistance (counter torque) increases the electrical rotor resistance. I think that's what the OP meant. – Janka Oct 25 '16 at 12:49