Electromagnetic relay working principle and characteristics
Electromagnetic relay is generally composed of iron core, coil, armature, contacts and so on. As long as a certain voltage is applied across the coil, a current flows through the coil, thereby generating an electromagnetic effect. The armature absorbs the tension of the anti-spring against the tension of the anti-spring under the action of electromagnetic attraction, thereby driving the dynamic contact of the armature. The point is in contact with the stationary contact (normally open contact). When the coil is de-energized, the electromagnetic suction force also disappears, and the armature returns to the original position under the reaction force of the spring, so that the movable contact is attracted to the original static contact (normally closed contact). This is sucked and released to achieve the purpose of turning on and off the power. For the "normally open" and "normally closed" of the relay, it can be distinguished as follows; the relay coil is not energized into the open contact, which is called the "normally open contact", and the static contact is in the on state. It is a "normally closed contact".
Thermal Reed Relays Working Principles and Features
Thermal Reed Relays are new thermal switches that use temperature sensitive magnetic materials to detect and control temperature. It consists of a temperature-sensitive magnetic ring, a constant magnetic ring, a reed switch, a thermally conductive mounting piece, a plastic substrate, and other accessories. The thermal reed relay does not use coil excitation, and the magnetic force generated by the constant magnetic ring drives the switching action. Whether the constant magnetic ring can supply the magnetic force to the dry spring is determined by the temperature control characteristics of the temperature sensitive magnetic ring.
Solid State Relay (SSR) Working Principle
The solid state relay is a four-terminal device with two terminals as the output terminals. The isolation device is used to realize the electrical isolation of the input/output. Solid state relays can be classified into AC type and DC type according to the type of load power supply. According to the switch type, it can be divided into normally open type and normally closed type. According to the isolation type, it can be divided into hybrid type, transformer isolation type and photoelectric isolation type.
Working Principle and Characteristics of Current Relay
The current relay is a relay that turns the circuit on or off according to the magnitude of the current in the coil. The coil of the current relay is connected in series in the circuit. In order not to affect the working condition of the circuit, the current relay attracts fewer coils and the conductor is thick. When the coil current is higher than the set value, the relay is called an overcurrent relay; when it is lower than the set value, the relay is called It is an undercurrent relay.