UVT COIL

UVT coil (Under Voltage Trip)

UVT coil is normally close point. When de-energized the coil MCCB will be trip. UVT coil is used to detect the phase.

SHUNT COIL

Shunt coil and UVT (Under Voltage Tripping) coil of the MCCB)

How to connect the shunt coil or UVT coil to the MCCB

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.

Protection of the MCB / MCCB

Protection of the MCB / MCCB

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

Thermal tripping

This action provides bimetallic part. It is used to protect the circuit from over load.

Electromagnetic tripping

This action provides electromagnetic field. It is used to protect the system from short circuit.

PUSH BUTTON

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.

RELAY - Reset mode

Reset mode

We can select two paths to resetting the overload relay.

1. Auto reset mode
2. Manual reset mode.

How to set the setting value of the overload relay

Assumed rated current of the motor is equal to the Ina = 18A

This setting is depends on the rated current of the motor.

RELAY

Feature of the Thermal Overload Relay

1. It has current setting dial. We can adjust the rated current of the motor.
2. It has trip indicator.
3. We can test the TOR (Trip On Not).

When trip the overload relay auxiliary contact point change. Therefore, cut the control circuit.

Feature of the Thermal Overload Relay

1. It has current setting dial. We can adjust the rated current of the motor.
2. It has trip indicator.
3. We can test the TOR (Trip On Not).

When trip the overload relay auxiliary contact point change. Therefore, cut the control circuit.