Buchholz Relay | Buchholz relay – Principle of operation

In large oil immersed transformers, we can find a cylindrical object installed in the pipe connecting the conservator to the main tank. This cylindrical object, that looks like a solenoid valve is called Buchholz relay. It is a type of oil activated relays. It can be found in all oil immersed transformers rated higher than 500kva. (more…)

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What is meant by stalling of motor?

Stalling is a condition at which a motor stops rotating even when there is sufficient voltage at it’s terminals. This condition occurs when the torque required by the load is more than the maximum torque (Breakdown torque) that can be generated by the motor. At this condition, the motor drains the maximum current and the speed comes zero.

Induction motor Torque-Speed Characteristics
Induction motor Torque-Speed Characteristics

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Asynchronous motor(Induction Motor) Starters | Comparison of induction motor starters

As the name indicates, starters are used to start or stop a motor. It consists of an electromechanical switch and protection devices (overload and/or short-circuit protection).

Why should we need a starter?

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Operation of generators

The generator is a device which converts the mechanical energy into electrical energy.

Construction

GeneratorIn order to understand the operation of a simple generator, consider rectangular coil ABCD placed in a magnetic field as shown in the figure. The two ends of the coil are connected to the two copper half rings (or split rings) R1 and R2 called commutator. There are two carbon brushes B1 and B2 which press lightly against the two half rings.

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