Question 1

The volts-per-turn for any transformer is determined by the ____.&#10;A) secondary winding&#10;B) primary winding&#10;C) primary current&#10;D) secondary current

Accepted Answer

The volts-per-turn for a transformer is determined by the primary winding because the voltage applied to the primary winding determines the magnetic field created, which in turn determines the voltage induced in the secondary winding. The secondary winding's voltage is dependent on the turns ratio relative to the primary winding, but it does not determine the volts-per-turn. The primary current and secondary current may affect the performance of the transformer, but they do not determine the volts-per-turn.

Question 2

A primary winding is a winding that is connected to a load.

Accepted Answer

A primary winding is a winding that is connected to a power source, not a load. The load is connected to the secondary winding.

Question 3

In a(n) ____, the secondary section contains more windings than the primary.&#10;A) autotransformer&#10;B) shell&#10;C) step-up transformer&#10;D) core

Accepted Answer

A step-up transformer has more windings on the secondary section than the primary, which increases the voltage of the output. Autotransformers have a single winding that acts as both the primary and secondary, while shells and cores are components that can be found in various types of transformers but do not determine the number of windings.

Question 4

Autotransformers are often used by power companies to provide a ____ increase or decrease to the line voltage.&#10;A) small&#10;B) constant&#10;C) variable&#10;D) proportional

Accepted Answer

Autotransformers are typically used to make small adjustments to the line voltage, either increasing or decreasing it slightly.

Question 5

Autotransformers can be used as step-up or step-down transformers.

Accepted Answer

Autotransformers can function as both step-up or step-down transformers, depending on the way the primary and secondary windings are connected.

Question 6

In an autotransformer with a 2:1 turns ratio, if a voltage of ____ is connected across the entire winding, a voltage of 240 volts will be supplied to the load.&#10;A) 120 volts&#10;B) 240 volts&#10;C) 480 volts&#10;D) 960 volts

Accepted Answer

With a 2:1 turns ratio in an autotransformer, applying 480 volts across the entire winding will step down the voltage to 240 volts for the load, as the voltage is directly proportional to the number of turns.

Question 7

Autotransformers cannot use multiple taps to provide different voltages.

Accepted Answer

Autotransformers can use multiple taps to provide different voltages.

Question 8

In a Variac, the windings are wrapped around a tape-wound toroid core inside a plastic case.

Accepted Answer

The windings are indeed wrapped around a toroid core, but the core is usually made of laminated silicon steel, not tape-wound. The core can be enclosed in a plastic case, but not always.

Question 9

The values of voltage and current for autotransformers can be determined by using standard transformer formulas.

Accepted Answer

Autotransformers follow the same principles as standard transformers for voltage and current calculations. Therefore, standard transformer formulas can be used to determine their values.

Question 10

A ____ is a winding that is connected to the source of power.&#10;A) filament winding&#10;B) secondary winding&#10;C) Kai winding&#10;D) primary winding

Accepted Answer

The primary winding is the winding in a transformer that is connected to the source of power. It is responsible for receiving the input voltage and transferring it to the secondary winding. The other choices (filament winding, secondary winding, Kai winding) are not typically connected to the power source in a transformer.

Deck 20: Autotransformers