Protection against internal phase-to-earth faults when the system is earthed can be provided by restricted earth fault protection. While not covering phase-to-phase faults this ar... Read more
If a fault occurs on a generator stator or its associated cables, the tripping of the generator circuit breaker alone is not sufficient Although the machine will be isolated from t... Read more
For each generator circuit breaker must be fitted with an overcurrent relay. On medium-voltage systems this is often an integral part of the circuit breaker, in In the form of dire... Read more
The fuse is a piece of wire which can carry a stated current; if the current rises above this value it will melt. If the fuse melts (blows) then there is an open circuit and no cur... Read more
Occasionally a transformer winding becomes completely shorted. In most cases, this activates the overcurrent-protective device (circuit breaker or fuse) and de-energizes the circui... Read more
Sometimes a few turns in the secondary winding of a transformer experience a partial short, which in turn causes a voltage drop across the secondary. The usual symptom of this cond... Read more
Dry-type transformers are a part of most electrical installations. They range in size from small doorbell transformers to three-phase 25-kVA units installed in electrical closets t... Read more
Avoid working “live” Electrical testing must often be performed on energized circuits and equipment. But the safest technique for doing tasks such as repairing and replacing faulty... Read more
