This quiz is designed for students who will be conducting an external exam on Appliance Motors and Circuits. Most questions in this exam are from past external exam papers.
90 electrical degrees
120 electrical degrees
180 electrical degrees
360 electrical degrees
0.1 ohms
10000 ohms
1 megohm
Infinite ohm
750 rpm
800 rpm
1000 rpm
1500 rpm
(i) Direction (ii) Magnetic Field (iii) Current flow
(i) Direction (ii) Current flow (iii) Magnetic Field
(i) Current Flow (ii) Magnetic Field (iii) Direction
(i) Current flow (ii) Direction (iii) Magnetic Field
Typical operating current of the motor
Maximum operating current that the motor can sustain under load
Maximum allowable starting current
Operating current with a 10% safety margin, as identified by the manufacturer
Non-automatic restart function and fail safe operation
The use of a three phase switch only for on/off control
Control over starting current and/or starting torque
Reduced voltage and torque at start
Are only used on a.c motors
Are only used on d.c motors
Can be retrofitted to most three phase motors
Are typically used for constant load applications
To any overload current regardless of current value
Faster to a larger overload current that to a small overload current
Shower to a larger overload current that to a small overload current
Faster to a smaller overload current that a larger overload current
A timer
Motor start fuses
A contactor fitted with an inverse time characteristic overload
A lock out circuit
To act as an overload device
To act as a starting device
To disable the run winding
To disable the start winding
Start 50-80 uf @ 240V : Run 4-20 uf @ 440V
Start 50-80 uf @ 440V : Run 4-20 uf @ 240V
Start 50 -80 uf @ 240V : Run 30-50 uf @ 440 V
Start 30-50 uf @ 440V : Run 30-50 uf @ 240V
Burnt out start windings
Dry, sticking bearings
Stator is inserted the wrong way around
It is not plugged in
The overall weight of the motor
Copper losses
Eddy current losses
Magnetisation losses
Electronic equipment failure, worn brushes
Bearing failure, arching brushes
Electronic equipment failure, open circuit electromagnet
Open or short circuit in the windings, bearing failure
Recording devices and washing machine agitator motors
Bottle cabinet fan motors
Delay timers and cordless drills
Clocks and timers
Increasing the load current
Decreasing the line current
Changing the number of poles in the motor
Connecting a capacitor in the starting circuit of the motor
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