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Can anyone confirm what readings I should be obtaining when testing for voltage phase-earth on a system which is ungrounded and has a ground fault. 440v phase-phase in normal operation. Would a voltage of 440v to earth indicate a ground fault or would you expect zero volts in the grounded phase...

Hi, Wondering if anyone can assist me. We have a 1.8MW Emergency generator that we usually carryout 3 weekly load runs on, normal practice is to auto synch with main generation. My question is we have a power management system controlling the main generators to a pre set base load 95% of...

One other question, would this set up still be adequate for use on an IT or floating earth system, given the fact the system can still run with 1 such fault!

ABB MCB is type S203MC10, 3 pole, 10A, 10KA, C Curve. In essence the set up I.e , ABB 10A MCB, 2.5mm2 3core SWA to supply a grinder rated at 440/3/60 2.24kW is adequate......?

Wondering if anyone can help me out, we have a 2.24kW pedestal grinder supplied at 440/60/3 - 0.85p.f - would using a 2.5mm2 SWA cable to supply be adequete with a 10A MCB protecting the cable. calculated the 3 phase current to be 3.5A - anyone suggest/comment on the cable/MCB used. Are these...

Can anyone describe how to test a brushless generator. Looking to test stator - no issues, PMG stator no issues, main excitor stator no issues. Will test diodes - no issues. Just need to clarify the exact correct way to test the rotor. Would disconnecting the diodes & dc cables from the diode...

Wondering if anyone can help here. We have an ABB ACV700 VFD, supplied by a 690vdc bus, 690vac to a step up transformer to 2600vac supplying a downhole ESP motor. Drive currently operating/running - however pump discharging very little....? Hertz = 3.5-4Hz, ref = -25.7 and current 413A. This is...

Yes that's correct, both would require splitting if it were ferments necessary to prove which phase was dragging the IR down, the dispute was that the delta configuration needed splitting regardless, which isn't the case.

Thankyou electricpete, The dispute was over how you complete an IR test, as stated it's identical for both Wye/delta. The opposing argument was that the delta configuration when tested needs splitting, not true as a low IR will be indicated regardless of doing so, only at the point of having...

Hi all, Can someone please state the correct method to adopt in testing a delta connected 3 phase motors insulation resistance, & how it differs from testing a star connected 3 phase motor. We are having a dispute on the matter & an un-baised opinion would settle the argument. Many thanks. EK

Another question guys. Proving dead any system should be regarded as live working until proven otherwise. Do we need to consider for LV/HV for proving dead purposes/testing live the use of Arc flash suits, and having an analysis done to identify boundaries/levels. Thoughts appreciated as at...

Much appreciated Scotty. Exactly same thoughts. I will however implement a routine control certificate for proving dead HV switchgear, the hazards can be pre-emptied and assessed. Thanks

So as such a generalised plan to cover all elect hazards. Not really feasible is my thoughts so risk assessing each time/to allow correct haz ID prior to breakdown work commencing - at the same time delaying response - although complying with EAWR 1989. when pressure is on not always case- I...

Marmite thanks for reply. Regarding elect safe working practices, a stipulation to pre planning for breakdown work scopes is mentioned. As each breakdown may differ in complex a routine template for such work in a sense dosnt control or ID all hazards/reducing risk to alarp. How can control be...

Switch operates on temp detection above set point, opening circuit. Fan motor operational, seems extremely hot within oven on switch activation. Any ideas......! Switch recently replaced, few months ago.

Can anyone explain to working of an industrial convection oven/steamer. What possible causes attribute to a safety thermal switch operating. Product Elamo B10-11, could a defective water inlet solenoid cause the thermal switch to operate due to stagnant heat not being circulated hence heat...

So with respect to purely HV testing, I.e proving dead prior to implementing the application of a CME, because it is unknown prior to proving dead that the system isn't actually live, my question is that as part of an isolation you apply a CME, but should you also have for proving such a system...

Scotty, Thanks for the reply, much appreciated. Have you any info or knowledge of when live working is unacceptable, circumstances or situations.

Can anyone outline what is required in terms of controls to conform to the EAWR 1989 Reg 14 - live work on LV system/in the proximity of live conductors. Your help would be appreciated

Can anyone explain the purpose of a blocking magnet within a 11kV ABB SF6 circuit breaker, what is it's function. Circuit breaker is motor charged with 1x shunt trip, 1x closing coil and a blocking magnet. Thanks for your help