ELECTRICAL MAGNETIC CONTACTOR
DEFINITION - WORKING - CONSTRUCTION
Definition:
- A contactor is an electrically controlled switch used for switching and electrical power circuit. The basic operation of this is similar to a relay. but the only difference is that contactor can carry a large current compared to relay up to 12500A. They cannot provide short circuit or overload Protection but can break the contact when the coil excites.
- A contactor is a relay that is used for switching power. It usually handles very heavy loads like an electric motor, lighting and heating equipment, etc.
- According to loads contactor or handle,and vary in size room a small device to as huge as yard.
- Unlike circuit breakers contactor used for switching purposes only, it does not interrupt a short circuit current like a circuit breaker.
Construction:
- A contactor consists of an electromagnet, contacts, and spring enclosed inside an enclosed. In some they have built-in economizers, that can reduce power consumption. Certain arrangements for arc extinction is also made inside for breaking the operation.
- An electromagnet is a key component in contactors without which it Cannot function.
- It requires an additional supply for excitation.
- It drains negligible current from the supply during excitation.
- These electromagnets will be hollow cylindrical in shape A rod with the spring return arrangement will be placed in the hollow cylindrical electromagnet
- In some contacts, this electromagnet is split into two halves. One of the halves is fixed and the other is movable power contacts are fixed to the movable electromagnet under normal condition, these two halves of electromagnets are held apart using a spring between in contact with AC coil, the electromagnetic core is made up of laminated soft iron to reduce eddy current losses and in contactor with DC coil, the electromagnetic core is made up of solid steel /soft ironic core since there is no risk of eddy current loss in DC
Function:
- The magnetic field is generated by the electromagnet in the magnetic contractor when the electricity starts flowing in the magnetic contractor. The magnetic field created is a strong magnetic field that pulls the iron core of the magnetic contractor in the coil and as a result, an electric arc is generated. The electricity is passed into the magnetic contractor in this manner. To stop the functionality of the magnetic contractor it is simply pulled off from the device it is attached with. When there is no electrical current in the magnetic contractor, the connection of the core with the coil is also disconnected
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