A compressor converts the mechanical energy of an electric or combustion motor into the potential energy of compressed air. Air compressors fall into two main categories Reciprocating and Rotary.
01. Piston type Compressors
02. Screw type Compressors 1) Trigger action push-pull
2) Trigger action turn to release.
Thermal overload relay is a one of the protective device, which protects the load [motor] from overload. There are many sizes are available. Also so many setting ranges are available. This setting time is depends on the rated current of the motor.
It has 3 no of power controlling poles and also has two auxiliary contact points such as normally open and normally closed.
UVT coil is normally close point. When de-energized the coil MCCB will be trip. UVT coil is used to detect the phase.
First trip the MCCB by using manual test button and after connect the UVT or shunt coil to the MCCB.
v Shunt coil
Shunt coil is normally open contact point. When energized the coil the MCCB will be trip.
| MCB | MCCB |
| 1. Short circuit | 1.Short circuit |
| 2. Over load | 2. Over load |
| | 3. Other protection |
Chart 03.04.01
MCB / MCCB has two mechanism to trip
1). Bimetallic part
2). Electromagnetic part
This action provides bimetallic part. It is used to protect the circuit from over load.
This action provides electromagnetic field. It is used to protect the system from short circuit.
There are many three types of push buttons are available.
1). Single headed push button, spring return.
2). Double headed push buttons, spring return.
3). Emergency stop and mushroom head push button.
