Developed by engineers for engineers.

### on what factors eddy current loss depends- Eddy current loss formula

The eddy current loss of transformer depends on the following factors.

• Supply Voltage
• Supply frequency
• Thickness of the volume
• Volume of core material
• Resistivity of the core material…

Continue

### Why is Core of the transformer laminated?

To minimize the eddy current losses, the iron core is formed using several thin electrically insulated sheets called lamination.

The current flowing in the sheet is equal to;

I= Potential…

Continue

### on what factors eddy current loss depends- Eddy current loss formula

The eddy current loss of transformer depends on the following factors.

• Supply Voltage
• Supply frequency
• Thickness of the laminated sheet
• Volume of core material
• Resistivity of the core material…

Continue

### CRGO Core for Transformer - Why? & Its advantages

C.R.G.O (Cold Rolled Grain Oriented) core is used in transformers to reduce eddy current losses and increase corrosion resistance. It also contributes to a reduction in coercive force resulting in a decrease in the loss of reverse magnetization in transformers.

### Active current: The current in the phase with the voltage is called the active current. Reactive current: The current lagging or leading with the voltage is called the reactive current. Read More:…

Active current:

The current in the phase with the voltage is called the active current.

Reactive current:

The…

Continue

### What Happens if frequency is increased/decreased keeping voltage constant in transformer?

The hysteresis loss is proportional to the frequency. The hysteresis loss should increase with an increase in the frequency, however the hysteresis loss remains almost unchanged. The reason is that the flux density in the core gets decrease in the same proportion of the increased frequency.

The eddy current loss is proportional to the square of the flux density and frequency. With an increase in the frequency…

Continue

### Formula of eddy current loss

Where K is constant, it depends on the resistivity of core material

f= frequency

Bm = Flux density

t = Sheet thickness

V = Volume of…

Continue

### Why laminated sheets are used in transformer?

That reduces the eddy current losses. When magnetic feild passes through iron core it produce a current we call it eddy current which is parallel to the magnetic feild so we laminate the iron core so that eddy current will minimum. Thats all we laminate iron core because we want to make more efficient transformers.

Continue

### What is NGR and why it is used in neutral grounding?

NGR is used in neutral grounding circuit to limit the earth fault current to the safe value of the equipment's rated current. It provide protection to equipment.

Continue

### At start what is the slip of induction motor?

At start, slip of the motor is unity.

When the motor starts accelerating, the slip decreases and at the rated KW the slip of the motor is about 3–5 % of the synchronous speed of IM.…

Continue

### Harmonics Filters – Cost and Effectiveness

The main characteristic of an electrical system is its waveform which, under all operating conditions and load conditions, must always remain a pure sine wave. Factors altering this sinusoidal wave shape can be said to be affecting the power quality within the electrical system.

The level of harmonics in present day electrical network is steadily increasing due to the introduction of energy efficient…

Continue

### Harmonics Filters – Cost and Effectiveness

The main characteristic of an electrical system is its waveform which, under all operating conditions and load conditions, must always remain a pure sine wave. Factors altering this sinusoidal wave shape can be said to be affecting the power quality within the electrical system.

The level of harmonics in present day electrical network is steadily increasing due to the introduction of energy efficient…

Continue

### Role of test and measuring instruments in harmonics studies

Now a days, latest state of art measuring equipments are available which measures the power quality accurately and analyzing tools are also available. Whenever, load structure is changed there is need to study the quality of power system. Remember, analysis of power quality is not a one-time job. Whenever a new nonlinear load is added to electrical network one should conduct the study on harmonics and reallocation of the power factor capacitors must be done if…

Continue

### Single VFD for multiple motors

Any numbers of motors can be connected to the VFD till the capacity of motors does not exceed above the capacity of the inverter. However, care should be taken to run all the motors starts simultaneously in order to have smaller size of the VFD. If the motors are not run simultaneously the size of the VFD will be bigger. The twin motors are used for those applications where two motors are used to share common load at same speed. The twin motors are used for driving…
Continue

### Working Principle of Active Harmonic Filter

The Active filter is IGBT based harmonics generator. The active harmonic fileter is connected in parallel to the load to be compensated. The harmonics present in the system is measured by the CPU  of active filter unit. The CPU controls the IGBT unit of the active filter. The CPU commands to the IGBT control unit to generate the harmonics spectrum in just phase oppostion to the measured harmonic spectrum in a real time basis to nullify the load harmonics. The…

Continue

### Single VFD for multiple motors

Any numbers of motors can be connected to the VFD till the capacity of motors does not exceed above the capacity of the inverter. However, care should be taken to run all the motors starts simultaneously in order to have smaller size of the VFD. If the motors are not run simultaneously the size of the VFD will be bigger. The twin motors are used for those applications where two motors are used to share common load at same speed. The twin motors are used for driving…
Continue

### What is the difference between 0.2 and 0.2S Class Current Transformer?

Accuracy class of 0.2 means +/- 0.2 % ratio error. But, the declared accuracy is guaranteed only between 100% & 120% rating. CT performance can be guaranteed from 5% loading. Below this load, the error is not guaranteed. It can be anything.generally these CTs are used for metering purpose. to achieve more accuracy 0.2s or 0.5s CTs available with us. this special CTs assure the accuracy class even with 20% loading. …

Continue

### Sizing of the VFD

Sizing of the VFD

In many applications the more than one motor is connected to VFD for driving the single mechanial load. The selection of the VFD is very important when more numbers of motors are connected to VFD.VFD capacity is of paramount importance while selection. The VFD KW rating must be selected to 110 % of the driven…
Continue

### Why double earthing of electrical equipment?

The double earthing is done to ensure that at least one earthing will be in operation if the other earthing gets disconnected. The equipment must be earthed at the two distinct positions of the equipment.

Also, with the double earthing the effective earthing resistance gets reduced because of the two parallel circuits.…

Continue

### What is knee point or cut-in voltage of PN junction

The minimum amount of voltage required for conducting the diode is called knee voltage and it is also known as cut-in voltage. before knee voltage diode behave like a high resistor(means it’s not conduct).

knee voltage is different for different elements for e.g for Si knee voltage is 0.7v, knee voltage is Ge 0.3v. To know more about knee or cut-in…

Continue

2021

2020

2019