Search results for query: *

At 7 MW power, it's most likely white metal bearings all through the drive system. Is it forced lube oil system with external pumps? If yes, you should have a battery operated DC motor lube oil system as a back-up since ac motor driven pumps lose power when the main motor loses power. Provide...

Thanks jghrist. Got it. Would it work if another phase is taken as 0 deg? (Wish I could give more LPS). Muthu www.edison.co.in

Thanks jghrist . Your calculation tracks what I measured at neutral. If I may ask, how did you arrive at 0, 119, 119 angles ? waross - Input voltages are pretty much equal. It's regulation that is the issue. I had the utility guy measure the voltages at their transformer end, which is about 600...

Neutral current at low load was 2 Amps jghrist - The angles between the phasors A1, A2 and A3? How would you plug in these angles in your Excel sheet? Muthu www.edison.co.in

Current phasor with full load Voltage phasor with full load (75 to 80 V drop in voltage with full load. Utility has been informed about poor regulation) 3 phase current THD on full load (not much) Measured neutral current 16 Amps with Fluke clamp-on. Muthu www.edison.co.in

Caveat. Today's readings at low loads of 40 Amps (not the previous ones). Also, there is a voltage regulation problem from utility side (430 V on low load to 370 V on high load). Current phasor (low load) Voltage phasor (low load Will post high load phasors later. Muthu www.edison.co.in

UPS 3 ph, 10 KVA - 2 nos. 3 ph, 5 KVA - 2 nos. 1 ph, 5 KVA - 1 no Muthu www.edison.co.in

3 phase input RMS current waveform. 3 phase input THD current waveform Do you see much of a phase angle difference here? There are no 400 V (RY, YB or BR) single phase loads. Only 3 phase air conditioners, UPS for computer systems, LED lights, fans. Muthu www.edison.co.in

Phase angles imbalance. Completely forgot it. Thanks, sushil and jghrist. Will check the current waveforms and come back. Muthu www.edison.co.in

3 Ph, 415 V, 50 Hz 4 wire, neutral solidly earthed system feeding a high school with 3 phase ac's, LED & fluorescent lamps, ceiling fans, UPS systems for computers, lab equipments etc. Current and voltage THD's in each phase <3%. Current harmonics 3rd to 13th less than 0.5% in all 3 phases as...

Swap 12&9, 11&8, 10&7 and see what happens. Muthu www.edison.co.in

Any electrical insulator is also a thermal insulator and so the bus will run hotter. Muthu www.edison.co.in

Just reverse one set of CT's. Muthu www.edison.co.in

dpc - Thanks. I use silver coating in our shop. Long time since I saw tinned copper. waross - Yes, I know, I was the one who did the inversion (rather poorly) as an example of top termination. FacEngr - Thanks. Logically, from the top termination does not pull the cable from the lug. Muthu...

Another Q. Is tinning copper bus bars still a good practice? Muthu www.edison.co.in

From bottom From top I personally think from top is better since the cable is not pulling down from the lug. Muthu www.edison.co.in

If you have access to do IR, then you have access to do HiPot. What is the problem here? Muthu www.edison.co.in

prc Aren't 55/65 deg C OTI and WTI alarm limits? Muthu www.edison.co.in

55 deg C is top oil temperature and 65 deg C is indirect winding temperature rise via CT and a resistor. Muthu www.edison.co.in

Fix a SS mesh under the opening to keep away the critters. Muthu www.edison.co.in