Search results for query: *

Gents (and ladies of course), I was called to investigate why when a standby generator was used at a local hospital expensive damage occured to light fittings and other electrical equipment on single phase circuits. It turned out that the generator star point was disconnected. The problem...

Is this a UK application ?

A client who recently had a factory burn down following an electrical fault has asked me to carry out a discrimination study across his network at another plant. The supply is comprised of a 300kVA 400v TPN supply, MCCB main switchgear with 15 downstream type B MCB sub main boards. The problem...

Veritas, if you go to the AREVA website the handbook for the CDG should be there and the function of the time multiplier explained. It's dead easy.

Ahandle, Have you considered a Midel filled TX. I understand the coolant is biodegradeable.

Possibly a gravity contactor. http://www.enbray.co.uk/General%20purpose%20Contactors.htm

roktgr, What country are you in ? In the UK we regularly deploy radio for reservior level control etc. Not sure if our hardware would be available or legal in the US

In the Uk the arrangement is as follows. 1. Transformer star point brought out to a link in the LV switchboard. 2. Neutral link connected to neutral bus. 3 Neutral bus connected to the earth bar via bolted link (For testing) 4. Earth bar connected to earth grid via bolted link (again for...

Bld 5, I agree a single line would be useful indeed essential if your question is going to be answered. In the UK for private embedded generators in parallel with the national grid the generator star points would be disconnected after synchronisation and the neutral carried by the duty...

Madomankh, Are you saying that you have a 500kVA transformer and the point of isolation is 3km away ?. Doesn't this raise some health and safety issues in terms of isolation for maintenance ? As a minimum I would have expected a remote transformer like this to be fitted with a throat mounted or...

Thank you both. The type of power system will be TNS according to the UK standard BS7671 so I think the 4 pole bus section scheme will the most appropriate in this case as the system will normally run with all bus sections open.(Do you call these bus couplers over the pond?) Not too sure about...

Gents, Imagine 3 off 11kv/400V transformers feeding an LV switchboard with bus section switches between each section. All interlocked to prevent transformers operating in parallel. (2 from 3 scheme). I say the bus section switches should be 4 pole to prevent earth fault circulating current and...

Scaifie, Sizing LV busbars is quite straightforward when they are in free air however when installed in an enclosure this is quite a different matter. I have seen 2 x 150 x 6.3 busbars rated at 3000A in free air when enclosed burn down a switchboard at full load. The CDA publication is quite...

Gentlemen, I am involved with the design of a water pumping station equipped with 3 centrifugal pumps fitted with 450kW (415V) each capable of delivering 112 l/s and the static head is 277 metres. The contractor has proposed star delta starters but I understand that on delta transition the...