1. increases core resistivity
2. increases the effective length of eddy current paths thereby increasing effective resistance to the flow of eddy currents
3. increases core permeability
4. reduces the effective length of eddy current path, thereby reducing effective resistance to the flow of eddy currents
increases the effective length of eddy current paths thereby increasing effective resistance to the flow of eddy currents
1. No change in voltage
2. Voltage decreases
3. Voltage rises
4. Voltage will rise, go through a maximum ai then decrease
Voltage rises
1. square of frequency and flux density to the power 1.6.
2. frequency and proportional to flux density to the power 1.6.
3. the square of frequency and proportiona the square of flux density.
4. frequency and proportional to flux density
frequency and proportional to flux density to the power 1.6.
1. copper loss
2. hysteresis loss
3. core loss
4. eddy current loss
core loss
1. SC test only
2. OC test only
3. Both OC and SC tests
4. test by an impedance bridge
Both OC and SC tests
1. become three times
2. become 1.5 times
3. become half
4. remain the same
become three times
1. no change in voltage
2. voltage decreases
3. voltage rises
4. voltage decreases, goes through a minim and then rises
voltage decreases
1. is sinusoidal and of the same frequency as the voltage source.
2. comprises the fundamental frequency (same as that of the voltage source) and the peaking third harmonic.
3. comprises the fundamental frequency and the depressing third harmonic.
4. is sinusoidal of frequency three times that time of the voltage source
comprises the fundamental frequency (same as that of the voltage source) and the peaking third harmonic.
1. the same as the steady-state magnetizing current
2. several times the steady-state magnetizing current depending upon the initial state of th residual flux in the transformer core.
3. several times the steady-state magnetizing current independent of the initial state of t!t residual flux in the transformer core.
4. twice the steady-state magnetizing currofl provided the core has no residual flux
several times the steady-state magnetizing current depending upon the initial state of th residual flux in the transformer core.
1. when operator is not available
2. when iron losses are to be reduced
3. when efficiency considerations can be ignored
4. when the transformation ratio is small
when the transformation ratio is small