Why your home’s (120v 15 circuit) does not overload tools that only use 1 amp, 2 amps, 3 amps (etc. anything less than the 15)?

Question

For example if I connect a 90v motor to a 120v battery source doesn’t that overheat and blow my motor?

Why is it though when it’s 120v from the wall then the motor is still fine?

In: Engineering

Answer 1

Having a 15A circuit doesn’t mean everything on the circuit gets 15A. It means that circuit will allow up to 15A to be drawn before the breaker pops. 

The devices connected to the circuit will only draw what they need. This is because of ohms law. V=IR. The V is constant so the current (I) is determined by the R, which is the device load.