About relay:
A relay is an electrical control device that can give a specified input quantity and hold it long enough to cause a predetermined step change in the controlled quantity in the electrical output circuit. When the input volume is reduced to a certain extent and maintained for a long enough time, it is restored to the initial state.
Relay is an automatic switch element with isolation function, which is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronic equipment, and is one of the most important control components.
Relays generally have an induction mechanism (input part) that can reflect certain input variables (such as current, voltage, power, impedance, frequency, temperature, pressure, speed, light, etc.); There is an actuator (output part) that can realize “on” and “off” control of the controlled circuit; Between the input part and the output part of the relay, there is an intermediate mechanism (drive part) for coupling and isolating the input, functional processing and driving the output part.
There are many types of relays, according to the input can be divided into voltage relay, current relay, time relay, speed relay, pressure relay, etc., according to the working principle can be divided into electromagnetic relay, induction relay, electric relay, electronic relay, etc., according to the use can be divided into control relay, protection relay, etc. According to the input change form can be divided into with or without relay and measuring relay.
The presence or absence of relays is based on the input amount of action, there is no input when the relay does not act, there is an input when the relay action, such as intermediate relays, general relays, time relays, etc.
Measuring relay is based on the change of the input to the action, the input is always present when the work, only when the input reaches a certain value of the relay action, such as current relay, voltage relay, thermal relay, speed relay, pressure relay, level relay and so on.
① Rated working voltage: refers to the voltage required by the coil when the relay is working normally. Depending on the type of relay, it can be AC voltage or DC voltage.
② DC resistance: refers to the DC resistance of the coil in the relay, which can be measured by a multimeter.
③ Suction current: refers to the minimum current that the relay can produce suction action. In normal use, the given current must be slightly greater than the draw current for the relay to work stably. For the working voltage added to the coil, generally do not exceed 1.5 times the rated working voltage, otherwise it will produce a large current and burn the coil.
④ Release current: refers to the maximum current generated by the relay release action. When the current in the draw state of the relay is reduced to a certain degree, the relay will return to the unpowered release state, and the current is far less than the draw current.
⑤ Contact switching voltage and current: refers to the voltage and current that the relay allows to load. It determines the size of the voltage and current that the relay can control, and cannot exceed this value when used, otherwise it is easy to damage the contact of the relay.
Relay (English name: relay) is an electrical control device, which is an electrical appliance that makes a predetermined step change of the controlled quantity in the electrical output circuit when the change of the input quantity (excitation quantity) meets the specified requirements. It has an interactive relationship between the control system (also known as the input loop) and the controlled system (also known as the output loop).
Usually used in automated control circuits, it is actually an “automatic switch” that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic regulation, safety protection and conversion circuit in the circuit.
Post time: 4 月-17-2025