Exciting Electrical Engineering Challenge!

What maximum size inverse time circuit breaker is permitted for a single phase 7.5 hp motor operating at 208 volts?

a) 30 amps
b) 40 amps
c) 60 amps
d) 80 amps

Final answer:

The maximum size inverse time circuit breaker permitted for a single phase 7.5 hp motor operating at 208 volts is 30 amps.

Are you ready for an electrifying challenge in the world of electrical engineering? Let's dive into the data and discover the answer together!

Explanation:

The maximum size inverse time circuit breaker permitted for a single phase 7.5 hp motor operating at 208 volts can be determined by calculating the full load current of the motor. The formula for calculating the full load current is:

Full Load Current = (Horsepower x 746) / (Voltage x Efficiency)

Using the given values, the full load current is calculated as follows:

Full Load Current = (7.5 x 746) / (208 x 1)

Full Load Current = 27.19 amps

Since safety regulations limit continuous use to 80% of the breaker current capacity, the maximum size inverse time circuit breaker would be 30 amps. Therefore, the correct answer is (a) 30 amps.