How to choose a good electromagnetic relay

Update:25-05-2019
Summary:

Electromagnetic relays are a common type of electrical […]

Electromagnetic relays are a common type of electrical equipment in industrial circuits. Many people who choose electromagnetic relays do not understand very well. There are many questions about how to choose good electromagnetic relays. How to choose electromagnetic relays?
1. Select the rated working current of the electromagnetic relay coil: DC electromagnetic relay driven by transistor or integrated circuit, the rated working current of the coil (normally 2 times of the pull-in current) should be within the output current range of the drive circuit.
2. Select the electromagnetic relay contact type and contact load: the same type of relay usually has a variety of contact modes available (electromagnetic relays are: single set of contacts, double sets of contacts, multiple sets of contacts and normally open contacts, often Closed contacts, etc.), the type of contact suitable for the application circuit should be selected.
3. Select the electromagnetic relay coil power supply voltage: When using the electromagnetic relay, first select the relay coil power supply voltage is AC or DC. The rated operating voltage of the relay should normally be less than or equal to the operating voltage of its control circuit.
4. Select the appropriate volume of the single-phase relay: The size of the relay is usually related to the size of the relay contact load. The relay with more than one product should be selected according to the request of the application circuit.
The relay is an automatic switching element with isolation function. It is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronics. It is one of the most important control components.