His coil has several joints, two or three, is it its auxiliary contact in series in the control loop
Voltage relay is an electronic control device, it has a control system (also known as the input circuit) and the control system (also known as the output circuit), usually used in automatic control circuit, it is actually a smaller current to control more Large current of a "automatic switch". So in the circuit plays an automatic adjustment, security protection, conversion circuit and so on. Mainly used for generators, transformers and transmission lines of the relay protection device, as over-voltage protection or low-voltage lock to start the original.
The relay coil has only two heads, plus the rated voltage after the coil flows through the rated current, the resulting electromagnetic force to overcome the spring force, through the electromagnetic mechanism to normally open contact closure, normally closed contact open.
Usually only the contactor is divided into main contacts and auxiliary contacts. Relays are usually used when the general contact in series or in parallel with the main circuit and control loop to complete the control task.
The key is to see what kind of voltage relay you need, in addition to the coil, there are voltage sampling contacts and output contacts.
The relay is divided into AC and DC, AC is usually 220V and 380V, DC is usually 5V-28V, many models. The principle is that when the coil with the power, will produce a magnetic field, through the core to the moving contact of the connection mechanism, so that the action and contact.
Electric shock is usually a single and three-phase AC, the main contact for high current, auxiliary contacts only for small current, such as control and light. Usually in the control circuit, the auxiliary contacts are mostly in series, with a coil connected to another long open contact, so that only one disconnect, it can only work, or coil button, button The other end is often open contact, so you can achieve the relay self-protection, that is, press the button after the pull, such as most of the motor is the reverse control is the case.
In addition, when the number of contacts is not enough to use, you can add extended contacts.
DC relay is very simple, the same single-contact and multi-contact, but not very obvious, such as the exchange of the main and auxiliary contact points.
Control, usually with low-voltage DC relay control high-voltage AC contactor (relay), to achieve personnel and equipment safety control.
The relay coil has only two heads, plus the rated voltage after the coil flows through the rated current, the resulting electromagnetic force to overcome the spring force, through the electromagnetic mechanism to normally open contact closure, normally closed contact open.
Usually only the contactor is divided into main contacts and auxiliary contacts. Relays are usually used when the general contact in series or in parallel with the main circuit and control loop to complete the control task.
