Ensayo de Transformadores

What is the main objective of the no-load test on a single-phase transformer?

• Determine losses in the windings

• Determine losses in the core and magnetizing current

• Calculate short-circuit impedance

• Verify the transformation ratio

In the no-load test, where is the ammeter connected to take measurements?

• In series with the secondary winding

• In parallel with the primary winding

• In series with the primary winding

• In parallel with the secondary winding

During the short-circuit test of a single-phase transformer, the secondary winding must be:

• Connected to a resistive load

• Open-circuited

• Short-circuited

• Connected to another transformer

What percentage of the nominal voltage is typically applied to the primary winding during the short-circuit test?

• 100%

• 50%

• 5-15%

• 75%

What problem can indicate excessive no-load current during the no-load test?

• Short circuit between turns in the secondary

• Problems in the magnetic core

• High short-circuit impedance

• Poor insulation quality between windings

In the short-circuit test, what instrument is used to measure losses in the windings?

• Voltmeter

• Ammeter

• Wattmeter

• Frequency meter

What electrical risk is sought to be detected when abnormal heating of the core is observed during the no-load test?

• Overvoltages in the secondary winding

• Short circuits between core laminations

• Poorly sized windings

• Low energy efficiency

To increase the applied voltage during the no-load test, one should:

• Do it instantaneously up to the nominal voltage

• Gradually increase it until reaching the nominal voltage of the primary

• Keep it at a low value to avoid damage

• Apply overvoltages to verify the robustness of the transformer

An abnormally low short-circuit impedance detected during the short-circuit test may indicate:

• Good quality core

• Reinforced insulation

• Problems in the windings

• Optimal operation of the transformer

In the no-load test, the wattmeter is connected:

• With the voltage coil in parallel and the current coil in series with the secondary winding

• With the voltage coil in parallel and the current coil in series with the primary winding

• With both coils in parallel to the primary winding

• With both coils in series with the primary winding