What is magnetizing current?
Magnetization current can be defined as “the portion of the no-load current that is used to establish flux in the core of a transformer“. Generally, when a transformer is energized under no-load conditions, it draws a small amount of current.
What is the importance of magnetizing current in machine design?
Magnetizing current and power factor being very important parameters in deciding the performance of induction motors, the induction motors are designed for optimum value of air gap or minimum air gap possible. Hence in designing the length of the air gap following empirical formula is employed.
Why magnetizing current of three phase induction motor is much more in magnitude than that of a three phase transformer of the same power rating?
(1) Unlike that of a transformer, the magnetic circuit of a 3-phase induction motor has an air-gap. This increases the reluctance of the magnetic circuit of the motor to a great extent. Consequently, the magnetizing current drawn by an induction motor is much more than that of a power transformer.
How can magnetizing current be reduced?
It is revealed that the primary winding of the transformer with concentric windings is optimally arranged further away from the magnetic circuit. This will allow to reduce the magnetizing current when working under load and to reduce iron losses.
What is the magnetizing current in a transformer is rich in?
Magnetic inrush current contains the dominant 2nd harmonic component of current. In order to avoid unnecessary tripping of the transformer due to magnetic inrush current, a second harmonic restraining coil should be used as a bias to the differential protection.
What is magnetizing inrush current?
Magnetizing inrush current in transformer is the current which is drown by a transformer at the time of energizing the transformer. This current is transient in nature and exists for few milliseconds. The inrush current may be up to 10 times higher than normal rated current of transformer.
What should be done in order to reduce the errors in the core?
1)Core : In order to minimize the errors the magnetizing current I„, and loss component I, must be kept to a low value. This means that the core must have a low reluctance and a low core loss.
What factors does the value of magnetizing current depends on?
How many factors does the value of the magnetizing current depends upon? Explanation: There are 3 factors upon which the magnetizing current depends upon. They are total mmf required, number of turns in the exciting winding and upon the way in which the winding is distributed.
Why no load current is more in induction motor?
As the air gap between the stator field winding and rotor winding is large, the more magnetizing current is needed to create flux which will cut the rotor conductor. So it is an important reason why Induction Motor draws more No Load Current than a transformer.
How do you calculate magnetizing current?
This is the magnetizing current ( no secondary current ) and is governed by the differential equation V(t) = L x d(I)/dt + Rp x I(t), with units of volts, henries, amps, and seconds.
What is no load current of a transformer?
Explanation: The no load current is about 2-5% of the full load current and it accounts for the losses in a transformer. These no-load losses include core(iron/fixed) losses, which contains eddy current losses & hysteresis losses and the copper(I2*R) losses due to the no Load current.
What is the main purpose of using core in a transformer?
The main purpose of using core in a transformer is to. prevent eddy current losses. prevent hysteresis losses. decrease reluctance of the common magnetic circuit.
Why do you need a magnetizing current in an induction motor?
The magnetizing current is essential for setting up a magnetic field in the air gap of the motor. Without magnetizing current, the magnetic field can’t be generated, and the motor operation is not possible. The stator winding is inductive in nature and when applied AC to the stator, it draws current that lags the applied voltage.
How does magnetizing current affect the power factor?
Effect of magnetizing current and its effect on the power factor can be understood from the phasor diagram of the induction motor shown in Fig.
Is the permanent magnet part of the electric motor?
The race for the electric cars has begun in the automotive industry and companies are vying for an edge in this market segment. The Permanent Magnet (PM) motor is a critical part in many electric car powertrain designs, which is undergoing rigorous improvement and changes.
Which is part of the magnetizing current does it take?
Magnetizing current takes place primarily via reactive current, so is partially out of phase with the active current and therefore appears, when taken out of context on a nameplate like this, to be a higher percentage of total current than it really is.