We have installed a 1970's vintage BVP17 type 11kV switchboard, made up of 17 CB's, manufactured by GEC (same as Reyrolle etc), and are in the process of connecting 2 new panels to the end of the board, with new 11kV busbar extensions. The original busbar was hi-pot tested at 27kV for 1 minute...
We have a 33kV transformer about to go for factory acceptance tests, and while this is a relatively small 300kVA unit, am unsure what voltage and duration should be used for the hi-pot test. What is recommended for such a unit? (Of note is that this unit is rated 170kV BIL).
What generally...
4.35MVA, 11kV motor is started direct on-line and has suffered from severe rotor bar cracking after about 4000 starts over 20 years. This has been repaired by a complete rebuild, but at almost 70% of the cost of a new motor.<br><br>What systems, including soft-starters and other techniques are...
