I have encountered a situation with GE motor starters where the OL selection chart for a size 5 starter with CTs and a 168 Fla at 150 hp calls for almost a double size heater element than what would be expected with a 5 amp secondary current on the CT. The heaters recommended by the chart would...
I would like to know what electrical parameters make the difference between a inverter grade thyrister and a phase control thyrister? I am tring to cross refrence an old obsolete inverter grade thyrister in an attemp to make a quick repair to a UPS system at my facility that has a shorted scr in...
I need to know which codes,API or ANSI ect., cover the installation of compresion and threaded steel tubing used in high pressure hydrogen gas service. This information is needed after an incident where a maintenance technican changed several 3/8" tubing valves in a valve/regulator tree fed by...
Does anyone have experience with switching the neutral instead of the "Hot" conductor in control circuits except in motor starter buckets. I have encountered this practice on a DCS system in a chemical manufacturing facility.I am told this is a safer practice in that all conductors in the field...
I have seen ground faults inside junction boxes at MV motors do a good deal of damage to the enclosures.(There have even been reports of fatal injuries to people near the motors when such happens.) Lots of "arc" damage will be present but not with my newest MV fun! In the most recent incident...
Why would a medium voltage (2300v)AC variable speed drive have a dual secondary (6 leads out) supply transformer feeding the the front side (12 pulse rectifier)of the drive?
Is this transformer needed of does it serve some added benifit?
What sort of problems should I expect if I have a 10 HP 1695 rpm motor driving one side of a 10 ton bridge crane and a 15 HP 1720 rpm motor driving the othe side of the same bridge? Both of these motors are powered by the same VFD that uses an open loop V/F control method.
I was wondering if there were any special considerations that should be known befor attempting to parallel 2 identical 3-phase induction motors on one vfd output.The motors will be driving a sled via rails. There will be a motor and gearbox at each side of the cart to drive the cart on the...
