EE 9

The boundary of the protection system is determined by the location of ___.

• protective relays

• circuit breakers

• current transformers

• voltage transformers

How much larger is the rotor reactance of a SCIM at start-up than it is when the motor operates at 5 percent slip?

• 5 times

• 25 times

• 20 times

• 10 times

Which of the following is the electrical device that is usually required to be installed in moisture area in the dwelling unit in order to protect the person from electric shock?

• Power Fuse

• Circuit breaker

• Arc-Fault Circuit Interrupter

• Ground-Fault Circuit Interrupter

Power factor of synchronous motor can be made leading by adjusting its:

• Supply voltage

• Excitation

• Speed

• Supply frequency

The effective resistance of conductor is increased by ___.

• Both skin effect and proximity effect

• proximity effect

• corona effect

• skin effect

For two alternators operating in parallel, if the load shared by one of the alternators is to be increased, the field excitation is ___.

• to be kept constant but input torque should be decreased

• to be kept constant but input torque should be increased

• to be strengthened keeping input torque the same

• to be weakened keeping input torque the same

In positive voltage sequence, which statement is true?

• V_LL is in phase with V_PH

• V_LL leads V_PH by 30°

• V_LL lags V_PH by 60°

• V_LL lags V_PH by 30°

What is the reason why thermal powerplant decrease capacity during summer?

• Temperature rise of the lake

• Decrease water level at the lake

• All of the choices

• Many people go swimming on lake

Increasing the voltage of the transmission system to double its original value with the same power to be transmitted, the new power losses of the transmission system will be ___ of the original value.

• one-fourth

• one half

• the same

• twice

Motors must be labeled with the following nameplate rating, manufacturer's name and etc. This is the:

• Wiring Design Rule

• Construction Rule

• Installation Rule

• Manufacturing Rule