Tag: contactor

When an electrical circuit has two contactors and only one of them needs to be turned on at a time then the interlocking system is used. The interlocking system ensures that only one contactor can be on while another one will be in off condition even if we try to manually on.

Contactors are used in electric power, distribution and electricity applications. A contactor refers to an electrical appliance that uses a coil to flow through a current to generate a magnetic field to close the contacts in order to control the load in industrial electricity. There are many types of contactors according to their purpose and characteristics.

The alternating current vacuum contactor (AC vacuum contactor) is a kind of on-off switch used in an AC power supply environment, which is widely used in various control circuits at present.

AC contactor is generally classified into class I, class II, class III and class IV according to the type of load, and they are respectively recorded as AC-1, AC-2, AC-3 and AC-4. AC-1 AC contactor corresponds to non inductive or micro inductive load as its control object, such as the filament lamp, resistor furnace. AC-2 AC contactor is used for starting and stopping of wound asynchronous motor. Typical application of AC-3 AC contactor is the operation of squirrel-cage asynchronous motor and the break in operation. AC-4 AC contactor is used for starting, reverse braking, reversing and jog of cage asynchronous motor. All ATO AC contactors with 24V/110V/220V coil operating at AC-3 380V or 660V.

As equipment to disconnect load power, selection of contactor should meet requirements of controlled equipment. Except that the rated operational voltage is the same with the rated operational voltage of controlled equipment, load power, usage category, control mode, operation frequency, working life, installation method, installation dimension and economy of controlled equipment are the basis of selection. How to choose a right contactor? The principles are as follows:

DC contactor is mainly used to control the DC circuit, it has no impact on the starting current, and will not produce iron core impact, so the service life is long, suitable for frequent start and stop occasions. ATO provides a wide range of DC contactors including universal DC contactors, high voltage DC contactors and DC reversing contactors. Rating current of them from 30 amps to 600 amps, available with 12V, 24V, 48V DC coil. Look at the price of ATO DC concactors listed in the table below, it's cheaper for you to get one from us.

Short circuit of the contactor
Possible causes of the fault:

• The contactor works in the environment of damp, dust, steam, or corrosive gases.
• The arc chute damages or falls, load short leads to the contact short of the contactor.
• Incorrect operation of the positive and reverse contactor, as well as unreliable interlocking, make two contactors to pull in at a same time when reversing.

Maintenance method:

1. Improve the working environment and keep clean.
2. Match an arc-extinguishing equipment again.
3. Handle the load short failure.
4. Recheck the contactor's interlocking circuit, change the operation mode.

Contactor is an automatic electromagnetic switch for long-distance frequently connected or disconnected AC and DC main circuit and high-capacity control circuit. The main control object of a contactor is the motor, it can be used to control other loads as well.
According to the current types that through the main contacts, contactor is divided into AC contactor and DC contactor. The structure and working principle of both are basically the same, which mainly consists of three parts, electromagnetic mechanism, contact system and arc-extinguishing equipment. In the electrical control circuit of machine tool, AC contactor is mainly used. This article focuses on the basic structure of the AC contactor.

A contactor is mainly used in a primary loop, which can go through a large current (several hundred to about one thousand Amps). While a relay is used in a secondary circuit to achieve various control functions, which can only go through a small current (several to decades Amps). Functions, contacts opening and closing situation of the two subject are different.