Electric Braking

Q. What are the requirements of good electric braking? Answer. The requirements of good electric braking are: (i) The braking should be quick and reliable in action. (ii) The braking must be controllable. (iii) Some suitable means must be provided for dissipation of kinetic energy of the moving parts of the motor and its driven … Read more

Parallel Operation of DC Generators

For supplying a large DC load, it is desirable to use more than one generator in parallel. This arrangement provides the security that if one generator gives way, the other(s) can feed part load. Desirable Conditions for DC Generators in Parallel Same voltage rating Same percentage voltage regulation Same percentage speed regulation of the prime … Read more

Electrical Machine Insulation

In electrical machines, the insulation system must withstand the high electrical stresses and severe mechanical stresses induced by the magnetic field of the moving rotor. In machines, multi-turn windings are put in narrow armature slots, which are usually grounded. Rotating machine stator insulation construction is divided into principal types: Random wound conductor machines with small … Read more

Insulating Materials for Power & Distribution Transformers

The insulating materials used in power and distribution transformers must possess the following properties: Good electrical properties to withstand the power frequency (50 Hz) voltages and impulse overvoltages. Good mechanical properties to withstand fabrication and handling during manufacture and electromagnetic forces during overload, short circuit, and normal operating conditions. Good thermal stability and low ageing … Read more

Transformer Noise Causes

Transformer Noise When you crossed across a transformer in your locality, you might have listened to the humming noise coming from the transformer. It is quite annoying if the transformer is located in a residential area. The cause of transformer noise is the magnetostriction. We have written an article on Magnetostriction topic. As we know … Read more

Distribution & Power Transformers

Distribution Transformers It is used to step down the distribution voltage to a level suitable for utilisation purposes at the consumer’s premises. Distribution Transformer has its secondary terminals directly connected to the consumer’s terminal. They remain in operation all the 24 hours a day. Distribution Transformers have good voltage regulation. Distribution Transformers have a small value … Read more

Difference Between Core type and Shell type transformer

The difference between Core type and Shell type transformer is given as below S.No. Core type Transformer Shell type transformer 1. It requires less iron. It requires more iron. 2. It requires more conducting material. It requires less conducting material. 3. It is used in low flux density applications. It is used in high flux density … Read more

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