Forum Replies Created
-
Posts
-
Power factor is related to lagging between current and voltage .
Of course, for a given load and voltage, power factor will change with frequency as relative impedances of coils and purely resistive loads will change.
I advise you nto go through the free elearning “get to know the main switchgear functions” that will answer most of your questions :
Hi Syed,
I always have the same reply : go to the reference guide ….
Wiki-Electrical Installation Guide : Reactive_energy_and_power_factor
Surge protection devices have to be selected after a complete study of the installation .
You will find good documents in
http://www2.schneider-electric.com/sites/corporate/en/customers/designers/designers.page
Download the following : CT 179 – LV Surges and Surge Arresters – LV Insulation Co-ordination
Could you please add details to your question ?
I presume that you are speaking of LV panels .
If the breaker trips, and there is no other switching device downstream, then anyway the load is unpowered . So the best way is first visual inspection and then disconnect the circuit as downstream as possible and measure the circuit impedance . If OK, repeat upstream until you locate the S C area .
Agree with holwa on discrimination for small ratings . Be careful to at least have a gap in the fuse ratings series . For example, you may loose discrimination with 10A, 16A, 25A . In this case, the three ratings are too close.
