In this first entry in my blog I'm going to talk to you about the relays. A relay is a switch controlled by current remote control, the magnetism, or the temperature. Relay is a component common in many devices and there are many different types of relays.
Types of Relays:
The two main types of relays are electromechanical and state solid. The relays use an electromagnet to move a series of contacts The contacts are attracted to the electromagnet, while that the current that flows to the contacts that are connected to a spring that pushes them up when the current stops flow. An interlocking relay acts as a two-pole switch in the contacts that remain in position when the current one stops flow. This is achieved by means of a solenoid to move a ratchet and the cam or by an electromagnet on both sides.
They have a set of ferro alloys and metal contacts inside of a glass tube. Close contacts is when in a field External magnetic is applied and reopening is eliminated. The relays are used as door sensors for the systems of alarm.
Overload relays are similar to the relays of cane, but use a bimetallic strip to move the contacts. At high temperature does that the double strip with the set of contacts.
Relays are used to control the flow of large currents with a small current. In the past they were widely used in telephone exchanges to pass calls, but in large part They have been replaced by digital equipment. They are used to change the motors and to protect them from overheating. It is to be noted that also the thermostats use an overload relay to turn off the current when the temperature rises above the required.
This is why it is very important to test all generations and types of protection relays. To avoid major problems! If someone wants to contribute their knowledge about relays or relay test equipment I will be happy to read it and respond it.