What is the difference between time relay and speed relay
The time relay is a kind of delay control relay. It does not make the contacts act immediately after receiving the action signal, but delays for a period of time to make the contacts act. Time relays are mainly used in various automatic control systems and motor start control circuits.
Since the time relay is mainly composed of windings and contacts, the symbol of the time relay should also include windings and contacts. Different types of windings and contact combinations can constitute time relays with different working methods.
There are many types of time relays, mainly damping type (airbag type time relay), electromagnetic type, electric type and transistor type (electronic time relay).
The speed relay is a relay that acts when the speed reaches a specified value. The speed relay is usually connected with the shaft of the motor when in use.
The rotor 2 of the speed relay is made of permanent magnet material and is coaxially connected with the motor. When the motor rotates, the permanent magnet rotor rotates with the motor. The cage winding 4 cuts the rotor magnetic field to generate induced electromotive force and current in the ring. The current in the ring acts on the rotor magnet. When the rotor rotates clockwise, the cage winding sleeve will deflect in the clockwise direction, and when the rotor rotates counterclockwise, the cage winding sleeve will follow the direction of rotation of the rotor. Deflection counterclockwise.
When the cage winding sleeve is deflected, the lower pendulum is driven to swing and the corresponding reed 6 or 9, thereby changing the on-off state of the clockwise steering contact on the left or the counterclockwise steering contact on the right.