Relay working principle pdf

1. What is the working principle of relay?
2. What are the 3 main parts of a relay?
3. What is the function of relay PDF?
4. Are relays AC or DC?
5. What is L1 and L2 in a relay?
6. What are the two types of relays?
7. Why is a relay used?
8. What is the function of relay unit?
9. Which relay is mostly used?
10. Why relay is used in PLC?
11. How do you test a relay?
12. What are the parts of relay?
13. What is the main part of relay?
14. What is a 3 phase relay?
15. What are the 3 main components of simple circuits?
16. What is T1 and T2 in relay?
17. How do you test a relay?
18. What are the 4 pins on a relay?

What is the working principle of relay?

It works on the principle of electromagnetism. The electromagnetic field that creates the temporary magnetic field is energised when the relay's circuit detects the fault current. This magnetic field moves the relay armature to open or close connections.

What are the 3 main parts of a relay?

A relay contains a coil, an armature, and at least one pair of contacts. Current flows through the coil, which functions as an electromagnet and generates a magnetic field. This pulls the armature, which is often shaped as a pivoting bracket that closes (or opens) the contacts.

What is the function of relay PDF?

The relay is an automatic protective and switching device which is capable of sensing abnormal conditions in electrical circuits. These are operated to open or close the load contacts in response to one or more electrical quantities like voltage and current.

Are relays AC or DC?

The working power of the AC relay is AC, and the working power of the DC relay is DC. The coil diameter of the AC relay is thicker and the number of turns is less, and the coil diameter of the DC relay has more turns than the thin wire diameter. The core of the AC relay has a short-circuit ring, and the DC does not.

What is L1 and L2 in a relay?

1. The two vertical lines that connect all devices on the relay logic diagram are labeled L1 and L2. The space between L1 and L2 represents the voltage of the control circuit. 2. Output devices are always connected to L2.

What are the two types of relays?

The three main types of relays are electromechanical, solid-state, and reed.

Why is a relay used?

Relays are used to protect the electrical system and to minimize the damage to the equipment connected in the system due to over currents/voltages. The relay is used for the purpose of protection of the equipment connected with it.

What is the function of relay unit?

The relay module function is mainly to switch electrical devices and systems on or off. It also serves to isolate the control circuit from the device or system being controlled.

Which relay is mostly used?

Electromagnetic relay

Electromagnetic relay is the simplest, oldest and most widely used relay. Its basic components are coils, magnetic cores, armatures, springs and contacts. The magnetic system is used to convert the input current into the mechanical power required for contact closure.

Why relay is used in PLC?

A relay is used to energize the starter, which, in turn, switches the motor voltage while the PLC controls the relay. Wired to provide a control sequence, relays may also be used for simple control schemes where a PLC would prove uneconomical.

How do you test a relay?

Touch the leads across the switch pins. A normally open relay should read open or OL. Energize the electromagnet coil with a 9-12V battery across the pins. The relay should make an audible "click" as the electromagnet coil energizes and closes the switch.

What are the parts of relay?

A simple electromagnetic relay consists of a coil of wire wrapped around a soft iron core (a solenoid), an iron yoke which provides a low reluctance path for magnetic flux, a movable iron armature, and one or more sets of contacts (there are two contacts in the relay pictured).

What is the main part of relay?

Main Parts of a Relay

There are two main circuits in the relay. The primary side and the secondary side. The Primary Circuit provides the control signal to operate the relay. This could be controlled by a manual switch, a thermostat or some type of sensor.

What is a 3 phase relay?

A three phase voltage monitoring relay, or phase monitor, is a common type of monitoring relay in the protection of high voltage and high current electrical systems. It monitors the voltage of the three phases and trips if any of them is outside of a predetermined range. This prevents damage to equipment.

What are the 3 main components of simple circuits?

A simple circuit is a circuit that contains the three basic components needed for an electric circuit to function. The three basic components are a source of voltage, a conductive path, and a resistor.

What is T1 and T2 in relay?

Terminals T1 and T2 are a thermally activated contact on the resistor to indicate an overheat condition of the resistor. The contacts are normally closed and open once the braking resistor temperature reaches 120 degrees Centigrade. The minimum voltage/current for these contacts is 24VDC at .

How do you test a relay?

Touch the leads across the switch pins. A normally open relay should read open or OL. Energize the electromagnet coil with a 9-12V battery across the pins. The relay should make an audible "click" as the electromagnet coil energizes and closes the switch.

What are the 4 pins on a relay?

4 Pin Relay

4 pin relays use 2 pins (85 & 86) to control the coil and 2 pins (30 & 87) which switch power on a single circuit. There are 2 types of 4 pin relay available; normally open or normally closed. A normally open relay will switch power ON for a circuit when the coil is activated.