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WorksheetsAC Motor Revision Part 2
Total questions: 15
Worksheet time: 8mins
What is the relationship must be exists between the voltage in nameplate and system supply voltage.
Within 2%
Within 4%
Within 10%
Within 15%
During Installations of motors it is found that the motor base is not correct in size. Who should this be reported to?
As indicated in the organizational procedures
The electrician
The foreman
The designer
What is the best way and type of AC motor to start applications required high torque?
Star type motors
Star- Delta motors
Delta type motors
DC Motors
The photo shows the end plate from single phase motor with a switch fitted. How is this switch used in the operation of the motor?
To cut the motor supply if it over speed
To open circuit of start winding after start up
To give over current protection
To indicate when full speed has been achieved
In an AC motor, the magnetic field decrease, when the current flow….
Increases
Fluctuates
Stays the same
Decreases
Which of the following is not a recognized component of single phase capacitor start AC motor?
Stator with a start and run winding
Low slip rotor
Slip Ring
Electrolytic Capacitor
What is meaning of abbreviation DOL
Direct on load
Direct on line
Drop out lock
Direct over load
A typical system for the starting of large motors is?
Delta
Star- Delta
Star
Delta – Star
The Field control type motor speed controller is not suitable for?
Shunt type DC motors
Compound type DC Motors
Series type DC Motors
All of above mentioned
The Phase current (IPH) in Delta connection is equal to?
IL
Vph /RL
IL* √3
IL / √3
The back EMF produced in running motors by?
Slip rings
Rotor
Stator
Capacitor
To reduce lateral loads and premature failure of the bearing in the motor during installation. We have to?
Remove the loads
Align the rotor shaft up correctly
Reduce the power source current
Reduce stator imbalance
The advantage of three wire control that the motor will automatically restart after an overload
TRUE
FALSE
Schematics show motors and control equipment in their “resting” or “shelf” state
TRUE
FALSE
Many types of overload protectors operate on the relationship between _____.
Heat and current
The neutral conductor and the earth
Branch circuits and feeders
Voltage and wattage
