Chapter 36
A centrifugal switch is generally designed to disconnect the start winding of a split phase motor when the rotor reaches what percentage of the rated speed?
75%
A SC motor produced 1100 pound feet of torque at starting when full voltage is applied to the motor. If the voltage is reduced to 50% during starting, how much starting torque will the motor develop?
825 pound feet
List 5 common starting methods for 3 phase squirrel cage motors
Across the line resistor or reactor starting autotransformer starting wye-delta starting part-winding starting
What advantage does a reactor have when limiting inrush current that is not available with a resistor?
Better starting torque
What electronic component is used in the construction of a solid state starting relay?
Thermistor
The potential starting relay can be used with what type of split phase motor?
cap start cap run or permanent slip cap motor
What is the most common device used to disconnect the start winding of a resistance start single-phase motor that is intended to operate in the open air
centrifugal switch
When connecting a current relay for the purpose of starting a single phase motor, is the coil of the current relay connected in series with the run winding or the start winding?
in series with the run winding
When a solid state starting relay is used to disconnect the start winding of a split phase motor, what prevents the thermistor from returning to a low value and reconnecting the start winding while the motor is running?
when temperature becomes high enough, the thermistor changes from low to high resistance. This disconnects start winding from the circuit.