Search results
Results From The WOW.Com Content Network
The two halves of each limb have an equal number of turns and are wound in opposite directions. With the neutral grounded, during a phase-to-ground short fault, a third of the current returns to the fault current, and the remainder must go through two of the three phases when used to derive a grounding point from a delta source. [5]
The resistance path is the total resistance back through the supply transformer; to measure this an engineer will use an "earth fault loop impedance meter". The application of a low voltage allows a small current to pass from the socket back through earth to the supply transformer and distribution board.
A different form of short-circuit testing is done to assess the mechanical strength of the transformer windings, and their ability to withstand the high forces produced if an energized transformer experiences a short-circuit fault. Currents during such events can be several times the normal rated current.
Condition monitoring of transformers in electrical engineering is the process of acquiring and processing data related to various parameters of transformers to determine their state of quality and predict their failure. This is done by observing the deviation of the transformer parameters from their expected values.
Since practical calculations involve a number of approximations and estimates, some judgment is required in applying the results of a short-circuit calculation to the selection of apparatus. [4] Making capacity i.e. maximum fault current , device can carry, if it is closed in to the fault should be considered.
Provide a source of ground fault current during line-to-ground faults. Permit the connection of phase-to-neutral loads when desired. [2] Earthing transformer with a zig-zag. Grounding transformers most commonly incorporate a single winding transformer with a zigzag winding configuration, but may also be created with a (rare case) delta-wye ...
Since the secondary of the transformer is open, the primary draws only no-load current, which will have some copper loss. This no-load current is very small and because the copper loss in the primary is proportional to the square of this current, it is negligible. There is no copper loss in the secondary because there is no secondary current. [1]
When a large fault current flows through the circuit breaker, this is detected through the use of current transformers. The magnitude of the current transformer outputs may be used to trip the circuit breaker resulting in a disconnection of the load supplied by the circuit break from the feeding point. This seeks to isolate the fault point from ...