We all know that relays come in many different categories and each has its own role. Commonly used relays include electromagnetic relays, magnetically held wet-spring relays, solid state relays, and the like. The electromagnetic relay can be divided into AC electromagnetic relay, DC electromagnetic relay, high current electromagnetic relay, small electromagnetic relay, bistable relay, counter current relay and so on. There are also many kinds of automobile relays. The cars are usually small lamps, low beam, high beam, horn, starter, preheating, signal, wiper, air conditioner, lifter, brake light, etc. The basic part of the electricity is basically used. There are relays. So what are the differences between signal relays and power relays?
Signal relays are generally used for monitoring and protection, and are used in secondary protection circuits of power distribution high voltage cabinets. For example, the transformer oil temperature exceeds 85 degrees, and the temperature monitoring indicator has a normally open contact closure. This contact string is on the coil circuit of the signal relay, so there is a signal that causes the signal relay coil to pick up and the signal relay action. The "light" word is dropped, and the high-voltage switch is disconnected, and the load of the transformer is removed, thereby protecting the transformer. However, there are many kinds of signal relays, and some are directly buzzer or flash as an alarm signal.
When the secondary protection circuit is activated, the signal relay is activated. It will accurately inform the person concerned which protection is the problem, and its appearance has a clear start sign.
A power relay is a device that can make a transition in one or more electrical output circuits when the input (or excitation) meets certain specified conditions. It can be used in a neutral point direct grounding system as a directional component for zero sequence current protection.
The above is the difference between the power relay and the signal relay. The data sheet should be carefully checked during the selection. Each relay has its own indicator, which is selected according to the design circuit requirements.