Exam 46: Compensating and Definite Time Control Starting

Time limit controllers can drive pumps, fans, and compressors.

A field failure relay is a single-pole control relay.

A field accelerating relay is used with starters to control low-cost speed motors.

The field accelerating relay_____________ the full field during the starting period and limits the armature current during sudden speed changes.

A heavy load has more inertia for the motor to overcome; therefore, _________is required to build up the counter emf.

The definite time limit acceleration provided by the timing relays means that the resistors remain in the line for a fixed time period___________ the motor is connected across the line.

The running contactor is closed _______after a definite time interval.

Time limit controllers can be used with series, shunt, or___________ wound DC motors.

When a DC motor starts, the generated counter emf across the armature is low.

Time limit acceleration has the disadvantage that the resistors might remain in the circuit and could burn out.