Power contactors and its importance

The Contactor is an electrically controlled switch which is used for converting/switching the electrical power circuit. The power consumption of the contactor is comparatively less than an electrical switch as it is directly controlled by a circuit. It has 24-volt coil electromagnet controlling 230-volt motor switch.

The power circuit switches are also used for the Power Contactors. When a realy functions as the switch, it provides electrical power through the contactors. Contactors have multiple functions, contactors are normally open the current and sometimes when the current load shuts off, then the coil will remain in the de-energized state. Therefore, a power contactor manages the load of current. Hence, buy powercontactors online and heavy load of .

The power circuit switches are also used for the Power Contactors. When a relay functions as the switch, it provides electrical power through the contactors. Contactors have multiple functions like they normally open the current and sometimes when the current load shuts off, then the coil will remain in the de-energized state. Therefore, a power contactor manages the load of current. Hence, buy power contactors online and avoid the heavy load of current.

1. Operational principle: -

The operating principle of the contactors is very simple in nature. Whenever the contactor's electromagnetic coil is energized, then the electromagnetic field is produced. This electromagnetic field attracts the metallic rod towards the gap inside the hollow of the cylindrical magnet.

2. Arc suppression:-

The failure of the contact protection results in the occurrence of electric current. And the electric arcing causes a significant degradation of the contacts, which suffers from significant damage. An electrical arc occurs between the two contact points (electrodes) i.e., the transition from a closed to an open or from an open to a closed. The break arc is typically more energetic and thus more destructive.

Most of the control contactors are of low voltages (600 volts and less) and are air break contactors; air at atmospheric pressure surrounds the contacts and extinguishes the arc when interrupting the circuit. Modern medium-voltage AC motor controllers use vacuum contactors.

3. IEC utilization categories:-

The current rating of the contactor depends on the utilization category. Example, IEC categories in standard 60947 are described as:

AC-1 - Non-inductive or slightly inductive loads, resistance furnaces

AC-2 - Starting of slip-ring motors: starting, switching-off

AC-3 - Starting of squirrel-cage motors and switching-off only after the motor is up to speed. (Make Locked Rotor Amps (LRA), Break Full Load Amps (FLA))

AC-4 - Starting of squirrel-cage motors with inching and plugging duty. Rapid Start/Stop. (Make and Break LRA)

Relays and auxiliary contact blocks are rated according to IEC 60947-5-1.

AC-15 - Control of electromagnetic loads

DC-13 - Control of electromagnets

(sources from wiki)

Ratings:-

Contactors are rated based on the load current per contact (pole), maximum fault withstands current, duty cycle, design life expectancy, voltage, and coil voltage. A general purpose motor control contactor may be suitable for heavy-duty large motors. It is also called "definite purpose" contactors. They can be adapted to such applications like air-conditioning compressor motor starting.

NEMA:-

NEMA contactors for low-voltage motors (less than 1,000 volts) are rated according to NEMA size, which gives maximum current rating. Ratings by horsepower is attached to the induction motors. NEMA standard contactor sizes are designated.

The above information on power cantactors will help you to buy a good power contactor. It can be shopped on the trusted portal – Eleczo.com as it is one of the leading E-Commerce platforms in India. We are siemens power contactor suppliers and schneider powercontactor distributors. We provide a wide range of discounts and offers. You also check our abb power contactors catalog for technical specifications.

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