Overload Relay

What is overload relay?

Overload relay opens the circuit of a motor and disconnects the motor from its power source if it exceeds a predetermined level or value. It is also overload release as it acts as a protective device

Thermal overload relays is similar to a circuit breaker only in terms of construction and use. As it will interrupt the power in the motor to protect the motor.  These relays comes under the category of control gear and signaling devices and are available in reset type of both automatic and manual and  are ideally used in AC compressor motor protection, motors in machines, cranes, and for pumps.

Selection of an over-load protection relay

AC or DC Relay must be accurately chosen so that it can improve the working life of the motor. Therefore, before selecting these accessories the need and purpose should be taken care. Some of the considerations while choosing an over-load relay include

1. Switching time
2. Operating environment
3. Coil voltage and current
4. Coil and Contact protection
5. Number and type of contacts
6. Contact current and voltage rating

Types of motor overload relay

Relays are categorized into different types depending upon their operating mechanism, application and parameters

1. Thermal overload relay- This type of relay is probably the most popular type, which gives overload protection and it operates by connecting a heater in the motor. They are sensitive to ambient temperatures.

Thermal overloads can be further divided into two types

Ø      Solder melting type 

Ø      Bimetal strip type

2. Magnetic overload relay- It operates by sensing the strength of a magnetic field caused by the current flow to the motor. They are not sensitive to ambient temperatures

Magnetic overload relays can be further divided into two types

Ø      Electronic

Ø       Dashpo

Advantages:

1. A Relay with ambient temperature compensation operates efficiently in wide range of temperatures. 
2. Electrical overload relay  is inexpensive
3. It provides accurate and reliable protection to motors
4. Lowers the  risk to burn motor
5. Over load relay provides improved current control

If relay switch are not chosen wisely their contact life tends to reduce and they often get damaged in long run. So if you are looking for an over-load relay then eleczo.com is the best source to find it, as relay suppliers, Eleczo aims in delivering genuine and tested products to its buyers. So why wait….Grab the best deals today on Eleczo.com