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Faulty, There should be no need to change any surge arresters if you change the NER. I assume the request to increase the value of the NER is to limit the fault current to the value of tyhe full rating of the largest Generator of Transformer. They are slighly inductive and this can be a...

Hi BigJake, Further to my previous answer perhaps this may be of more use. It is nescessary to convert all reactances to a common kVA or MVA which ever is your preference. The value of this base is quite unimportant and may be, 1. That of the largest plant 2. That of the total plant capacity...

Skeandhu, In order to share correctly you should have the controls set for droop (as Bigamp states) and the AVR's and Governors set regardless of rating of the sets to the same settings, typically 4%. Having one set in Isoch will cause problems as its flat response will fight for the load or...

dougjl, Before the days of the "bean counters" an old engineering rule of thumb was to size motors so they ran at 80% of the duty thus giving the spare capacity required. I still apply this rule but just don't advertise it too much. Cheers, Coingy

Acmebunny, It could have a capacitor of size up to 800 mfd. Cheers Coingy

Acmebunny, For the custom fit method using busbars physical size method. First make available the capacitor leads and both sides of the start winding. Apply power to both the start and run windings with the rotor locked. The voltage across the capacitor and the start winding should be recorded...

EP, Our company standards would be a 1kV megger test with a minimum IR of 100 Mohms. It is not a normal test for a PI on a cable and I am not sure why this has been specified. A PI minimum of 2 is for equipment. Cheers, Coingy

Isaacs, Overload and Overcurrent should not be confused as the protection relays perform completely different functions. An overload relay operates in the hundreds to thousands of seconds range whereas an overcurrent relay operates in the one to ten second range. Cheers, Coingy

Hi jake, Years ago a Dutch colleague of mine when I was working in Holland gave a pamphlet for short circuit calculations which I refer to on and off as required. The address on the pamphlet where you may be able to obatin a copy is:- Point-To-Point Method For Short Circuit Calculations...

The rule of thumb I've always used is 6 x for large transformers, say, 2MVA and above. The smaller transformeres due to the larger inductances can be 14 x.