Item specifice

Contactors are divided into AC contactors (voltage AC) and DC contactors
(voltage DC), which are used in power, power distribution and power
consumption. Broadly speaking, contactor refers to an electrical appliance that
uses the current flowing through the coil to generate a magnetic field and
close the contact in order to control the load.
main features
The AC contactor uses the main contact to open and close the circuit and the
auxiliary contact to turn on the control circuit.


The main contact is generally normally open contact, while the auxiliary
contact often has two pairs of normally open contact and normally closed
contact. Small contactors are often used as intermediate relays to cooperate
with the main circuit.


The contact of AC contactor is made of silver tungsten alloy, which has good
conductivity and high temperature ablation resistance.


The power of AC contactor action comes from the magnetic field generated by AC
through the coil with iron core. The electromagnet core is composed of two
"mountain" shaped young silicon steel sheets. One of the fixed iron core is
sleeved with coil, and the working voltage can be selected. In order to
stabilize the magnetic force, a short-circuit ring is added to the suction
surface of the iron core. After the AC contactor loses power, it returns by
spring.


The other half is a movable iron core, whose structure is the same as that of a
fixed iron core, which is used to drive the closing and breaking of the main
contact and auxiliary contact.


Contactors above 20 amps are equipped with arc extinguishing cover, which can
quickly break the arc and protect the contact by using the electromagnetic
force generated when the circuit is disconnected.

The contactor can operate at high frequency. When it is used as the power on
and off control, the maximum operation frequency can reach 1200 times per hour.


The service life of contactors is very long. The mechanical life is usually
millions to 10 million times, and the electrical life is generally hundreds of
thousands to millions of times.
working principle

The working principle of the contactor is: when the contactor coil is
energized, the coil current will generate a magnetic field. The generated
magnetic field causes the static iron core to generate electromagnetic suction
to attract the moving iron core, and drives the AC contactor to act. The
normally closed contact is disconnected and the normally open contact is
closed. The two are linked. When the coil is powered off, the electromagnetic
suction disappears, and the armature is released under the action of the
release spring to restore the contact, open the normally open contact and close
the normally closed contact. The working principle of DC contactor is a little
similar to that of temperature switch.