Evaluation Exam 10 Flashcards
The electric motor generally used in household food mixer
A. Shaded Pole
B. Universal
C. Split Phase
D. Capacitor Start
Universal
In the transformers,
A. high tension winding is used near the core
B. high tension winding is used away from the core
C. low tension winding is used near the core
D. low tension winding is used away from the core
high tension winding is used near the core
21 is the device function number for this relay.
A. Undervoltage relay
B. Overvoltage relay
C. Distance Relay
D. Directional power Relay
Distance Relay
What device is used to measure the temperature of a motor winding while the motor is in operation?
A. Seismic probe
B. Thermocouples
C. Resistance temperature detector
D. Proximity Probe
Resistance temperature detector
Which of the following is NOT a reason why single-phase induction motor run?
A. two windings are displaced from each other
B. hysteresis
C. one of the current is made out of phase between the lines
D. shaded poles
hysteresis
Copper loss of a transformer are determined by means of a/an _____ test.
A. open circuit
B. polarity
C. short-circuit
D. inductive-circuit
short-circuit
Which of the following motors is generally used in toys?
A. Reluctance motor
B. Hysteresis motor
C. Shaded-pole motor
D. Two-value capacitor motor
Shaded-pole motor
Power lost due to alternating magnetization and demagnetization of the core material.
A. copper loss
B. eddy current loss
C. hysteresis loss
D. rheostat loss
hysteresis loss
If the per unit impedance is x pu, what is the new per unit impedance when both base power and voltage are doubled.
A. x
B. 2x
C. 0.5x
D. 4x
0.5x
What is the effects on current flow does in reversing the direction of movement of a conductor in the magnetic field of a generator?
A. It will increase the current flow.
B. It reverses the direction of current flow
C. It will neutralizes the current flow.
D. IT has no effect on the current flow
It reverses the direction of current flow
A step-down transformer is used to
A. increase the power
B. decrease the power
C. increase the voltage
D. decrease the voltage
decrease the voltage
The purpose of providing dummy coils in the generator is
A. to reduce the eddy current losses
B. to enhance flux density
C. to amplify voltage
D. to provide mechanical balance for the rotor
to provide mechanical balance for the rotor
The current flowing in the armature of a dc motor is
A. ac
B. dc
C. ac as well as dc
D. transients
ac
In a DC steady state, a capacitor behaves like a/an ______, while an inductor behaves like a/an _______.
I. short
II. open
A. I and III
B. II and I
C. II and III
D. I and II
II and I
When the amplitude of the oscillator in a series RLC circuit is doubled, the _________.
A. current amplitude is doubled
B. voltage across the capacitor is halved
C. impedance is doubled
D. capacitor reactance is halved
current amplitude is doubled
In a purely resistive ac circuit, the current
A. lags behind the emf in phase
B. leads the emf in phase
C. is in phase with the emf
D. leads the emf in half the cycle and lags behind it on the other half
is in phase with the emf
The net reactance in a series RLC circuit is
A. XL
B. XC
C. XC + XL
D. XL - XC
XL - XC
When the current and voltage are out of phase by 90 degrees, the power is
A. Average
B. Zero
C. Maximum
D. Minimum
Zero
The power factor of incandescent bulb is
A. 0.8 lagging
B. 0.8 leading
C. unity
D. zero
Also heater is unity ; Answer is unity
The impedance triangle is similar to the _________ triangle with the resistance phasor in place of the __________.
A. current, resistor current
B. current, resistor voltage
C. voltage, impedance
D. voltage, resistor voltage
voltage, resistor voltage
Which of the following does not refer to electric energy?
A. Joule
B. Watt Second
C. Volt Coulomb
D. Volt Ampere
Volt Ampere
It is the value of the sine wave of voltage or current at one particular instant of time.
A. Average value
B. Instantaneous vlaue
C. Effective Value
D. Maximum VAlue
Instantaneous Value
