Instantaneous Overcurrent Protection (I or ANSI 50)

Presentation

Instantaneous protection helps to protect equipment against phase-to-phase, phase-to-neutral and phase-to-ground short circuits. The protection operates with a definite time characteristic. It trips without additional time delay as soon as the setting current is exceeded.

Availability

Instantaneous overcurrent protection is available on:

• TS 2.0 and 2.0S, 5.0 and 5.0S, and 6.0S trip system

• 3-pole and 4-pole circuit breakers

Instantaneous overcurrent protection is powered by the current flowing through the internal current transformers of the circuit breaker and it does not require an additional external power supply.

Operating Principle

The instantaneous overcurrent protection pickup sets the level of short-circuit current at which the circuit breaker trips with no intentional time delay.

Instantaneous overcurrent protection overrides short-time overcurrent protection when the instantaneous overcurrent pickup is adjusted to the same or a lower setting than the short-time overcurrent pickup.

Setting Instantaneous Protection for TS 2.0 and 2.0S

The instantaneous protection pickup li is set by using the Ir and li rotary switches on the front face of the TS trip system.

The setting value is expressed in multiples of Ir long-time protection pickup.

1. Set the Ir long-time protection pickup.

2. Turn the Ii rotary switch to the value required.

3. Ii pickup = Ii setting x Ir pickup.

   NOTE: When Ir is set to off, Ii pickup = Ii setting x In rated current.

The Ii setting values are: 1.5, 2, 2.5, 3, 4, 5, 6, 8, 9, 10. Accuracy: +/-10 %.

Setting Instantaneous Protection for TS 5.0 and 5.0S, and 6.0S

The instantaneous protection pickup Ii is set by using the Ii rotary switch on the front face of the TS trip system.

The setting value is expressed in multiples of In rated current.

1. Turn the Ii rotary switch to the value required.

2. Ii pickup = Ii setting x In rated current.

The Ii setting values are: 2, 3, 4, 5, 6, 8, 10, 12, 13, 15 and off. Accuracy: +/-10 %.

The off setting disables the instantaneous overcurrent protection.

Predefined Events

Predefined events cannot be modified by the user. For general information about events, refer to Event Management.

Recommended Actions

Resetting a Trip Event

For information about resetting the circuit breaker after a trip due to an electrical fault, refer to the relevant document:

• EasyPact MVS1 Circuit Breakers with TS Trip System - User Guide
• EasyPact MVS2 Circuit Breakers with TS Trip System - User Guide