What is contactor and types?

The contacts are classified as power contact, auxiliary contact, and contact spring. There are two types of power contact; stationary contact and movable contact. The material used for the contacts has stable arc resistance and high welding resistance. These materials must withstand mechanical stress, erosion, and arc.

Why are contactors used?

Why are Contactors Used? Contactors are used for high power applications. They allow a lower voltage and current to switch a much higher power circuit, so they are generally larger and more heavy-duty than control relays, enabling them to switch higher power loads on and off for many thousands of cycles (Figure 1).

What are the parts of a contactor?

A contactor consists of three basic parts: the operating coil, the associated magnetic circuit and the contacts that are actuated by the coil.

How does a relay work?

Relays are electric switches that use electromagnetism to convert small electrical stimuli into larger currents. These conversions occur when electrical inputs activate electromagnets to either form or break existing circuits.

Why contactor is used?

A contactor is a special type of relay used for switching an electrical circuit on or off. They are most commonly used with electric motors and lighting applications.

What is the symbol for a contactor?

The contactor is designated as K and, in the coil symbol, the K1/4 indicates that there are four associated contacts. Sometimes the coil designation is placed beside the coil symbol. In this case there are three normally open power contacts, and one normally open control contact.

What is ITH on a contactor?

What is thermal current rating (Ith) for contactors? It means the rated current of this contactor which can switch for thermal Load category AC1 is = Ith. Contactors have two currents values, One is current for thermal loads which are loads that transfer electrical current into thermal energy. i.e all types of heaters.

What do the numbers mean on a contactor?

These auxiliary contacts (also called control contacts) each have an order number and a function number. The first number is used consecutively (order number) and the second number specifies the type of contact (function number).