If the main secondary breaker has ground fault protection, do we still have to protect the transformer shifted curve on delta-solidly grounded wye transformer against phase-ground faults which is shifted to the left?
Folks,
Does anybody know wehre I can get a device to generate variable milliamp current (AC) between 100-600mamp
I am not looking for a fancy device. Just a simple mamp ac current generator. I know I can use voltage and resistor ;however I need it to be controlled via a HMI or PLC.
I am looking for a meter to detect unbalanced current. This means if one phase current is more than 10% in difference with other two ,the unit initiates a trip.
I also have one set of CT’s which are source for Crompton Ammeters. There is diagram for connecting two meters in series, is this going...
If I run an AC motor without a load, and the voltage drops current drops too.in what situation if the voltage drops ,current goes up. I guess when I have a load on the shaft and motor tries to compensate for that load right?
Please refer me to articles on this subject.
Thanks
Attached is a result of coordination study of a fault fiter fuse( S&C ) and low voltage ckb. What margine need to exist between the inrush point and the fuse curve to safely order the fuses?
a 750KVA ANN transformer secondary side breaker is ordered with a 1000AMp LTP and fixed LTD . This is 1.4 times more than Tx FLA at 600V. Breaker is rated for 100% rated name plate operation.
Two issues is first the primary S&C fuse at 25KV does not coordinate with a 25 AMp fuse ( they touch at...
Assuming no size limitation, what is the standard (specified) size of these labels (eg 4 x 6 inches)?
Is there a code or regulation to print these labels on a specific size?
Quote"
In a delta system, the loss of one phase results in sensor readings with magnitudes slightly more than 1/2 of normal phase-to-phase voltage. Simultanious loss of two phases is not detectable as a phase imbalance condition.
Does this line make sense?
Hi ,
I have a CO-11 Relay which under CT Ratio shows Value=160 and under Remarks I have
3 X 3200/(2400)/2000/(1600)/1000:5 A
The Instantanious PU is 4800.
I am confused how to project this on TCC curve and also what are the meanings of those CT ratios?
where did they get 160 from?
I appreciate...
I am looking for TCC curve for Westinghouse breaker type CO-11.and ASEA breaker Type RXIL24-111DM .Does anyone know where I can get them from.
Thank you
If a single phase transformer primary is connected to L-L voltage, only one half of the three-phase short circuit MVA( GE SC calculation Manual, Page 33).Does anybody have reference to this calculation?
Thank you,
Dear Friends,
Could somebody give me some direction on how to solve equations in attached document? If possible I’ll like to create small user-friendly application software which could show the results when inputs are entered.
I know that this could probably e done with “C’ ,but It’s been long...
I had a bad experince in my previous job. I gave my resignation letter to the boss. 1 week before quit date.
I though this will give them enough time to wrap up the projects and other stuff.
BAD IDEA.....
They started being nasty.. at the end of the day they threted me like a criminal, checking...
In a 3 wire grounded system, if the main breaker has a ground fault function, the CT's common will need to be connected to ground terminal of the relay.
I know that in this case the sum of three currents will pass to ground and create a signal to activate the relay.
How the setting and...
Is meggering a lightning arrestor really a good test to show if the LA is good or not?
I usually test the 8KV and above Las at 5Kv and if I am reading more than 1000MG then I assume its good reading; however I am told that intermediate La’s are resetting themselves and meggering a LA is not a...
