Question 1

Most AC inductive loads such as motors or transformers have a high wire resistance.

Accepted Answer

AC inductive loads like motors or transformers are designed to have low wire resistance to improve efficiency and reduce energy losses.

Question 2

When the SCR is used for voltage control, if current is to flow to the load, it must pass through the SCR, which is connected across the positive and negative points of the bridge rectifier.

Accepted Answer

The SCR (Silicon Controlled Rectifier) is used in voltage control applications and is indeed connected in such a way that the current flowing to the load must pass through it. This allows the SCR to control the voltage and current supplied to the load by adjusting the timing of its conduction phase.

Question 3

If DC voltage is applied to a pure resistance, adverse conditions can occur.

Accepted Answer

When DC voltage is applied to a pure resistance, it simply causes a current to flow through the resistance according to Ohm's Law (V=IR), without causing adverse conditions.

Question 4

The triac is most often used to control ____.&#10;A) direct current&#10;B) alternating current&#10;C) hybrid current systems&#10;D) indirect current

Accepted Answer

The triac is most often used to control alternating current (AC) because it can conduct in both directions, making it suitable for AC applications.

Question 5

When the SCR is used for voltage control, a ____ is connected in series with the load resistor.&#10;A) gate inverter&#10;B) bridge inverter&#10;C) gate rectifier&#10;D) bridge rectifier

Accepted Answer

A bridge rectifier is used in conjunction with an SCR for voltage control to convert AC to DC, allowing the SCR to control the output voltage by adjusting the phase angle of the AC input.

Question 6

If DC voltage is applied to a load that is ____, a great deal of damage can be done.&#10;A) inductive&#10;B) resistive&#10;C) capacitive&#10;D) indirect

Accepted Answer

Inductive loads can cause a large current surge when DC voltage is applied, which can damage the load or the power supply.

Question 7

When variable AC voltage is to be connected to an induction motor to perform the job of speed control, both halves of the AC waveform are not required to be conducted to the stator of the motor.

Accepted Answer

For effective operation and speed control of an induction motor, both halves of the AC waveform are necessary to ensure a smooth and continuous magnetic field rotation in the stator, which is essential for the motor's operation.

Question 8

When a DC voltage is applied to an inductive load, the current is limited by ____.&#10;A) the voltage&#10;B) the inductive resistance&#10;C) the wire resistance of the coil&#10;D) the capacitance of the wire

Accepted Answer

The current in an inductive load when a DC voltage is applied is primarily limited by the wire resistance of the coil, as inductance does not resist DC current after the initial transient phase.

Question 9

When an AC voltage is applied to an inductive load, the current is limited by ____.&#10;A) inductive reactance&#10;B) inductive capacitance&#10;C) inductive interference&#10;D) inductive transference

Accepted Answer

Inductive reactance is the property of an inductor that limits the flow of alternating current (AC) through it. It is directly proportional to the frequency of the AC signal and the inductance of the coil.

Question 10

Thyristor devices such as the SCR and triac control the voltage by chopping the waveform.

Accepted Answer

Thyristor devices like the SCR (Silicon Controlled Rectifier) and triac control the voltage applied to a load by chopping the AC waveform, allowing only parts of the waveform to pass, thereby controlling the effective voltage and power delivered to the load.

Deck 26: Other Methods of Ac Voltage Control