Circuit breaker Part 11: Operation and Control Part 3

Counter:

The counter is a non-resettable electromechanical counter that counts every close operation.

MCB – Miniature Circuit Breaker:

The MCB (Miniature Circuit Breaker) is a small automatic breaker that can be manually controlled or automatically tripped due to over-current.

The MCB is normally used for AC auxiliary circuit (and motor circuit for operating mechanism type BLK).

Direct On Line Motor Starter:

Direct On Line Motor Starter is motor protection and manual control unit.

This unit trips the motor supply when a motor overload occurs or when the Direct On Line Motor Starter is manually operated.

Heaters, Thermostat, Humidity controller:

Every operating mechanism has a continuously connected anti-condensation heater of 70 W. In addition to that, one or more controlled heaters are fitted, depending on ambient temperature or humidity. 

These are controlled by a thermostat, or as an option, a humidity controller (a moisture detector controller).

Spring charge supervision:

As an option a relay can be fitted to give an alarm when one or more of the errors/events below occurs:

1. Loss of motor voltage.

2. The direct online motor starter is tripped manually.

3. The direct online motor starter is tripped due to over-current.

4. An electrical error prevents spring charging.

5. A mechanical error prevents spring charging.

The alarm delay must be at least as long as the spring charging time, normally 15 s.

0-voltage trip coil:

The operating mechanisms can be equipped with the 0-voltage Trip coil. It is used to automatically trip the circuit breaker at the loss of, or low operating voltage. 

The 0-voltage Trip coil is always used together with a voltage supervision relay that controls the tripping voltage level.

Fuses:

Fuses can be fitted in every circuit on request.
The trip and close circuits should preferably not include fuses.