Fusless Current Limiter in Breaker
Fusless Current Limiter in Breaker
(OP)
Does anybody know how the Current limiter in a breaker works? Typically a breaker has 25kA interrupting capacity which goes upto 100kA with this fuseless current limiter which sits at the load end of the breaker.






RE: Fusless Current Limiter in Breaker
RE: Fusless Current Limiter in Breaker
The breaker with a current-limiter - the current-limiter is a fuse that is integrally mounted on the breaker.
A current-limiting circuit breaker. As David mentioned, if the breaker can open fast enough, it becomes current-limiting because the current is interrupted before it reaches a maximum peak current in the first-half cycle. Specially designed and tested breakers can achieve this by having contacts that are forced open before the breaker actually trips.
RE: Fusless Current Limiter in Breaker
RE: Fusless Current Limiter in Breaker
RE: Fusless Current Limiter in Breaker
RE: Fusless Current Limiter in Breaker
One caveat—I understand that you give up selective coordination with other overcurrent devices when you apply current-limiting circuit breakers.
RE: Fusless Current Limiter in Breaker
If you use this to 'increase' the downstream breaking capacity then you will lose discrimination between the circuit breakers.
This doesn't mean that using a current limiting CB in a circuit precludes full discrimination being available. If the downstream breakers are fully rated for the prospective kA there is no problems (as long as the manufacturer shows discrimination between the CBs).