What are the main components of high voltage DC contactor

Typical high-voltage direct current contactors consist of a coil and contact point, which can be energized continuously by a rated voltage. When a current is applied to the coil, a magnetic field is generated and attracts the moving core to open the contacts. The contact repulsion force is related to the geometry of the current flow through the contacts. The magnitude of the field-induced repulsion force is proportional to the square of the current. In the case of blow-on electrodynamic forces, the nominal contact force is reduced. It is necessary to ensure that the contactor's circuit is able to shut off within a few seconds when the contacts are open. This is achieved by ensuring that the current through the contact point is below the minimum effective current for each phase.

The contactor is made up of a solenoid that is mounted within a metal frame. The plunger acts as an actuator and is biased by springs to open and close the contacts. When the plunger contacts are closed, they stop on the frame. The axial position of the solenoid is glued to retain the contactor during its life.

The contactor can be divided into two types, namely a dual coil contactor and a single coil contactor. The dual coil contactor progresses the contacts when a polarized current is applied to the reset coil. When the polarized current is reversed, the single coil relay moves the contacts in one direction.