What is a change over relay?

What is a change over relay?

Change-Over Relays. A Change- Over relay is the most common type of relay. These have 5 pins and a body with two contacts connected to a common terminal. These are wired to be either Normally Open (NO) or Normally Closed (NC.) The Change-Over relay can control two different circuits, one NO and one NC.

What happens in a relay switch?

Relays are switches that open and close circuits electromechanically or electronically. Relays control one electrical circuit by opening and closing contacts in another circuit. As relay diagrams show, when a relay contact is normally open (NO), there is an open contact when the relay is not energized.

What does a electrical relay do?

The relay permits a small amount of electrical current to control high current loads. When voltage is supplied to the coil, small current passes through the coil, resulting in a larger amount of current passing through the contacts to control the electrical load.

What is the working principle of relay?

Relay works on the principle of electromagnetic induction. When the electromagnet is applied with some current it induces a magnetic field around it.

What is 86 on a relay?

Realizing that 85 and 86 are the coil pins, these pins will be transferring the current through the coil. 85 will be used to ground your relay, while 86 will be connected to the switchable power. 87 and 87a will be connected to your controlled accessories that you wish to turn on and off with your relay.

Why use a relay instead of a switch?

While a relay does add an extra step to the switching process, the main advantage is that you can leave the actual switching of high-power circuits for things like off-road lights or air compressors in the engine compartment, and control that switching with a much smaller amperage circuit that energizes the relay’s …

What are the 5 applications of relay?

Applications of Relays in Electronic Circuits

• Relay Drive by Means of a Transistor.
• Relay Drive by Means of SCR.
• Relay Drive from External Contacts.
• LED Series and Parallel Connections.

What is 5V relay?

A 5v relay is an automatic switch that is commonly used in an automatic control circuit and to control a high-current using a low-current signal. The input voltage of the relay signal ranges from 0 to 5V.

When does the contact of a relay change?

If one or more of the above electrical quantities change, that signals the presence, type and location of the fault to the Relay. After detecting the fault condition, Relay pick-up, its contact will change from NO to NC or vice versa. So we can wire up a particular kind of Relay contact to Breaker tripping circuit.

How are relays used in an electrical circuit?

How Relays Work. Relays are switches that open and close circuits electromechanically or electronically. Relays control one electrical circuit by opening and closing contacts in another circuit. As relay diagrams show, when a relay contact is normally open (NO), there is an open contact when the relay is not energized.

What causes an electromechanical relay to move?

The coil of wire causes an electromagnetic field to be created when the current is switched on an causes the armature to be attracted. Armature: This is the moving part of the relay. This element of the relay opens and closes the contacts and it has a ferromagnetic metal to be attracted by the electromagnet.

What happens when a relay is not energized?

As relay diagrams show, when a relay contact is normally open (NO), there is an open contact when the relay is not energized. When a relay contact is Normally Closed (NC), there is a closed contact when the relay is not energized. In either case, applying electrical current to the contacts will change their state.