Automatic switching element is a relay having a function of isolation, is the most important element of control. A switch having an automatic control system and the control system), typically used in automatic control circuit, it is actually a smaller current to control a large current. It plays in the automatic adjustment circuit, a security role, conversion circuit.
1 relay action
Relay generally reflect some input variables have a sensing means able to perform the controlled circuit implementation mechanism off control; the input section and output relay between the portions, as well as coupling isolation input, processing, and the function of the intermediate output portion for driving the mechanism.
As a control element, sum up, there are several relay functions:
1) increase the control range. For example, when the multi-contact relay control signal reaches a certain value, may be set according to different forms of contacts, for access at the same time, breaking, circuit switched multiplexer.
2) amplification. E.g., relay, relay and so sensitive, with a very small amount of control, a large power can be controlledCircuit.
3) automatically, remote control and monitoring. Relays on the robot, together with other appliances, process control circuit may be composed of, in order to achieve automated operation.
4) the integrated signal. When a plurality of control signal input in the form of a multi-winding a predetermined relay, through a more integrated, predetermined control effect.
2. Relay Category
(a) by the working principle
1. The electromagnetic relay
Under the action of the input circuit current, produces a predetermined response to the relay by the relative movement of mechanical parts. It comprises a DC electromagnetic relay, AC electromagnetic relay, latching relay, polarized relay, a reed relay, a power saving relay.
(1) DC electromagnetic relay: current input control circuit for the electromagnetic relay DC.
(2) alternating electromagnetic relay: current input control circuit for the exchange of electromagnetic relays.
(3) magnetic relays: introducing the magnet a magnetic circuit, the relay coil is deenergized, the relay armature when the coil is still held in the energized state, has two stable states.
(4) polarized relay: state changing depending on the input amount of polar A DC excitation of a relay.
(5) a reed relay: using sealed within the tube, having the dual role of contact springs and the armature magnetic circuit tongue movements to open and close the relay or switching circuit.
(6) saving power relay: current input control circuit for the exchange of electromagnetic relays, but the current is large (typically 30-100A), small volume, power-saving features.
2. Winds relay
When the wind speed reaches a certain value, the controlled circuit on or off.
The solid-state relay
input, output one kind of a relay without mechanical moving parts is completed by the electronic component.
4. Polarized relay
has a combined effect of a magnetic field and polarized magnetic field generated by the current control coil controlling the operation of the relay. Directional relay operation depends on the control current flowing through the coil in a direction.
The relay
When adding or removing the input signal, the output portion or the need to delay time to a predetermined limit to close or open the relay circuit which is controlled.
6. The temperature relay
When the ambient temperature reaches a predetermined value sometimes relay operation.
7. The acceleration relay
When the acceleration of the moving object reaches a predetermined value, the circuit will be controlled on or off.
8. Other types of relays
The optical relay, the relay sound, thermal relays.
(b) the guard feature points
1. Relay seal
by welding or other means, the contact and sealed in a metal coils an inner cover, a lower leakage rate relay.
2. Plastic relay
The method of the sealant, the seal contacts and coils in the plastic jacket, a high leakage rate relay.
3. Dust relay
contact with the casing to be closed and the relay coils protection.
4. The open relay
No guard to protect the contacts and relay coils.
(c) By Application
1. Communication relay
Such relay contact load range from low to medium current, less demanding environmental conditions. Relay
2. Machine relay
used in a machine tool, the contact load power, long life.
3. The appliance relay
Relay used in household appliances, requires good safety performance.
4. The automotive relay
Relay use in automobiles, such a large load power relay switches, impact, high vibration resistance.
The safety relay
relays for safety functions. The main products are represented by Pilz for the security control of the series.
(iv) classification by Dimensions
A micro-relay 1.
is not greater than the longest side dimension of 10mm relay
subminiature relay 2.
the longest side dimension greater than 10mm, but not more than 25mm relay
3. small relay
the longest side dimension greater than 25mm, but not more than 50mm relay