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Debashish... the error in the MW transducer would certainly explain it, IFF, the Reverse-Power Protection signal was derived from this transducer. Regard, Phil Corso

Charz... following are two reasons PFC for large motors should be limited to less than 80% of the no-load magnetization requirement: 1) Overvoltage. When a motor and its PFC are switched-off together, the motor becomes "self-excited" because the capacitor supplies the motor's magnetization...

Rashid... your explanation of screen earthed at both ends caught my eye. 1) How is system neutral earthed? 2) What method is used for earth-fault detection? (a) Residually connected Phase CTs (b) Zero-sequence (window-type) CTs? Phil Corso

Charz... The capacitive reactance, 150kVAr(c), could lead to severe over voltage if it remains connected to the motor you cited during the run-down trial. PF Correction or Compensation (PFC) should not be greater than the motor's no-load magnetization reactance which, for this motor, is...

Sriram... contact me off-list: Phil Corso (cepsicon [at] aol [dot] com)

Ronnie... Unless shown differently on the transformer's nameplate, the impedance is based on its OA (45 MVA) rating. Furthermore, impedance is not altered for operation at other capacities. However, tap setting does affect reactance. Regards, Phil Corso (cepsicon [at] aol [dot] com)

Vince... although the commercial instrument may cost a few grand, the "OFW" needs only a short length of cable, a multi-phase power source, a DMM, knowledge of vector math, and last, but not least, a small piece of chalk (any color will do!) Regards, Phil

Adeel Imtiaz... several additional questions 1) Are motors mounted vertically? 2) What type of enclosure is provided? 3) Have IR (Insulation-Resistance) tests been done? 4) Is monitoring instrument equipped with open-circuit detector? Regards, Phil Corso

Charz... can you provide motor rating (V, A, Hp, Rpm) and its associated capacitor size, Mfd? If there is a group of motors, then submit the information in Table form! Regards, Phil

Sriram... do you intend to use a commercially available transformer testing instrument? Or do it the old fashioned way? Regards, Phil Corso

Vince... first a little background to my story. Located in the heart of Newark, NJ, Ironbound community received its name from the fact that it was surrounded on all sides by railroad lines. It contained a few industrialized plants, several of which, like Celanese and Ballantine, had...

Thiragusriram... is the xfmr new? Or is it being reloaded? Regards, Phil Corso

JMW... the first, "Aluminum-Ball-Seconds" was a dimensional unit used by Celanese Plastics Company, to measure the viscosity of melted cellephane! The second, "Tennis-Ball-Bounces" was a dimensional unit used in an LNG-to-Gas plant to monitor the leak-rate in a cryogenic heat exchanger's...

Mohammad... I suggest you search the Control.Com Archives for the following Thread #: 1026209342, "480 Vac EMI to 24V DI Signals" Regards, Phil Corso

Dilip... the system you describe is somewhat like the classic "unbalanced 3-phase resistive" circuit. However, apparently information in this thread is not quite what you are looking for. To get idea of the unbalance magnitude you face, please provide: A) the 3 line-line voltages. B)...

Rasfid... see Control.com Thread # http//control.com/thread/1026247457 "Flashing of Vacuum Breaker" Regards, Phil Corso

Rashid.. my understanding of your problem is that: 1) A plant motor is supplied power from the 33 kV bus, presumably via a "captive transformer" whose Voltage Ratio is 33kV to some lower MV value? Or, 2) Are you talking about a 3.3 kV motor and breaker? Or, 3) Some arrangement other...

A2A... See Control.Com Thread 1275355681, "Time Delay For Reverse Power!" If, after reading the thread, you still have additional questions, let us know! Regards, Phil Corso

Caroline... contact me off-list. Phil Corso (cepsicon [at] aol [dot] com

Francis... feel free to post my off-forum comments to you! Phil Corso