Note: To achieve large voltage changes, taps should be placed Near the center of the phase winding to reduce magnetic asymmetry. It is usually done on windings placed outside.

Where are the taps of the transformer?

Typically, tapes are provided in middle of high voltage winding For the following reasons, 1) Fine voltage regulation is possible due to the high number of turns of the high voltage winding. 2) The low-voltage winding of the transformer carries a large current.

Why provide taps on the high pressure side?

high pressure side High voltage but low current But on the low-voltage side, the voltage is smaller and the current is larger. If we connect the tap changer on the LV side, sparks will occur. … HV windings are usually wound over LV windings, so it is easier to access HV winding turns than LV windings.

What is a tap on a transformer?

A tap changer is a Mechanisms in transformers that allow variable turns ratio to be selected in different steps. This is done by connecting to a number of access points called taps along the primary or secondary winding.

Why provide respirators in transformers?

respirator for transformers filter out moisture from the air. The respirator is composed of silicone that absorbs moisture from the air. … at low oil temperatures, the oil volume is reduced, causing air to enter the oil conservator.

Transformer MCQ Part 2

27 related questions found

What happens if the transformer is connected to DC power?

If the primary of the transformer is connected to a DC source, The primary will draw a steady current, resulting in a constant flux. Therefore, no back EMF is generated. … care must be taken not to connect the primary of the transformer to the DC power supply.

Why doesn’t DC use a transformer?

As mentioned earlier, transformers do not allow DC input to flow through. This is called DC isolation.This is because DC cannot produce current changes; This means that no changing magnetic field induces a voltage on the secondary components. … a simple to operate transformer.

What if the frequency of the transformer changes?

What happens to the frequency change of the power transformer. So if the frequency increases, Secondary voltage or electromotive force increases. and the secondary voltage decreases as the supply frequency decreases. …but at high frequencies, transformer losses increase, such as core losses and conductor skin effects.

What is Transformer Ratio?

The transformer turns ratio is The number of turns of the primary winding divided by the number of turns of the secondary winding. The transformer turns ratio provides the desired operation of the transformer and the corresponding voltage required for the secondary winding.

What is the rated voltage of the transformer?

with a transformer 100 VA For example, a rating may handle 100 volts at one amp (amp). The kVA unit stands for kilovolt-ampere, or 1,000 volt-ampere. A transformer rated at 1.0 kVA is the same as a transformer rated at 1,000 VA and can handle 100 volts at 10 amps.

Why do you need Olt?

The purpose of the tap changer is to adjust Transformer output voltage. It does this by changing the number of turns in one winding, thus changing the turns ratio of the transformer. … OLTC changes the transformer ratio when the transformer is energized and carrying a load.

Where is Oltc connected?

On-load tap-changer or OLTC

tap arrangement, placement In a separate divertor tank connected to the main tank of the power transformer. Inside this tank, the tap selectors are generally arranged in a circle.

Why do you need to tap?

Therefore, it must be Tap the high voltage winding This is advantageous in step-down transformers. Variations in taps can cause variations in leakage reactance, core losses, I2R losses, and possibly some problems in parallel operation of different transformers.

Which side is the high voltage side of the transformer?

Transformer high voltage (HV) side

The side of the transformer consisting of high-voltage windings is called the high-voltage side. See the diagram below for the high voltage side of the transformer. The high voltage side of the transformer carries the high voltage or high voltage windings.

What is a current transformer Mcq?

Current transformers are A device for converting a current from a higher value to a current proportional to a lower value. The ratio of the primary current to the secondary current is called the current transformer ratio of the circuit. The current ratio of the transformer is usually high.

What is the function of the oil accumulator in the transformer?

Transformer storage tank

The main function of the transformer oil storage tank is to Provide enough space for the expansion of the oil inside the transformer.

What are the three types of transformers?

There are three main types of voltage transformers (VT): Electromagnetic, Capacitive and Optical. Electromagnetic voltage transformer is a wound transformer. Capacitive voltage transformers use capacitive voltage dividers and are used at higher voltages because they cost less than electromagnetic VTs.

What is the Transformer Turns Ratio Test?

The power transformer turns ratio test is An AC low voltage test used to determine the ratio of a high voltage winding to all other windings at no load. The turns ratio test is performed on all taps of each winding.

What is the formula for a transformer?

Vp=-NpΔΦΔt V p = – N p Δ Φ Δ t . This is called the transformer equation and it simply says that the ratio of the secondary voltage to the primary voltage in a transformer is equal to the ratio of the number of loops in its coils.

Does changing the voltage affect the frequency?

as voltage increase The power and frequency outside the area will also increase. This oscillation of power, voltage and frequency can last for several seconds. During this time, the frequency response will begin to recover frequency.

Can a transformer change the frequency?

Transformers cannot change the frequency of the power supply. If the power supply is 60Hz, the output is also 60Hz. …the frequency of the system changes as the system load increases or the generator shuts down; the speed of the other generators is adjusted so that the average system frequency remains nearly constant.

Can a 60Hz transformer run at 50Hz?

Transformers rated at 60Hz should not be used on 50Hz supplies due to higher losses and core saturation, and the resulting higher temperature rise. However, a transformer rated at 50Hz, Operates on 60Hz power.

Does a transformer convert AC to DC?

The term AC to DC transformer refers to a transformer connected to an AC rectifier circuit. After raising or lowering the AC voltage, Rectifier circuit converts AC voltage to DC voltage. . . You’ll usually find AC to DC transformers in the form of adapters that plug into an electrical outlet.

Which of the transformers is not a loss?

What is no-load loss (excitation loss)? It is a loss in a transformer that is excited at rated voltage and frequency, but does not connect the load to the secondary.No-load losses include Core loss, dielectric lossand winding copper losses due to excitation current.

Which of the transformers are impossible?

Also, we cannot use DC Because the DC current is a constant current, there is no mutual inductance and the transformer will not work, so there can be no DC current in the transformer.