I have a regulated power supply 60VDC at 10A which I need to reduce to 42VDC
Can anyone please point me in the right direction. I know about 3 term regulators but most have a limited current rating
Would anyone know of a good source of commercially available low pass filters to reject 475HZ ripple frequency into 230AC 50HZ 60A loads? The ripple frequency is upsetting LEDs over a wide range of households
Perhaps not the place for this question but I cant find the answers anywhere!
Small closed loop controllers such as the CL57T and LCDA257S allow settings from 800 to 51,200 pulses/rev from the encoders they connect to. There is only two encoder connections on these modules.
Most of the small...
If you look at many generation plant connections from MV to HV then the MV (say 11kV) bus is often unearthed until the generator synchronises.
The popular idea is that there is no earth return from the MV to the HV and hence, no fault current, no step and touch potential issues, and little man...
Using supplier published MTBF and the e^(-lambda*T) methods for a PLC rack with CPU/Backplane and I/O the unavailability comes to a staggering 1900 hours a year.. Has someone got any sensible fault tree analysis information for PLCs
Micom have a published paper that says that the MTBF of a P341 relay as 30 years. This gives a probability of unavailability of 287 hours/year (12 days) which seems ridiculous. Similarly a 16 module PLC rack, using the same idea of summated lambdas (1/MTBF) and probability of reliability as...
I am looking for some typical information on the phase capacitve currents of transformers.
I have a specific need for the selection of a neutral earth NET/NER on a small generator. The specification requires the sizing to be the greater of 10A or 3 x Icap where Icap is calculated from the...
Hi
I am going around in circles with CT burden calculations… Can someone assist
Say we have the following
Ip= 100A, Is=5A, Type=5P, ALF=10, VA=15 and say Rct=0.2 ohm, Rl=0.45 Ohm (50 metres of 4mm2) and Relay Resistance Rr= 0.004 ohm and the fault level is 900 A and the maximum running current...
I understand generally the problems with not matching the winding pitch of generators synchronised together; this is the subject of several threads in this forum. What I do not understand is which pitch is better for an isonchronous load. I have a Cummins white paper dated 2013 that says...
An industrial site has a 14MVA 11kV load and 6MVA of embedded generation. The site is supplied from 2 x 20MVA transformers
The 11kV breaker on each transformer is fitted with a 260A directional OC (back into transformer) which is graded with a 260A directional OC on the site incomer.
Why would...
Hi We have an application for two 11kV generators to supply a local load and export to a 33kV system. The specification for supply says that the generators must operate in island mode so in this mode the 33kV will have to be earthed. We expect the 11kV should also be earthed for the local...
I have a client that has large block loads on an industrial plant that each have high VFD driven harmonics. He has implemtented mitigation ( active harmonic units) for one block and now is thinking about the second block to be commissioned next year. Using phase shifting power transformers...
I was amazed to learn that your average synchcheck relay will not detect the wrong phase rotation on one side (say a generator). Even the phase to phase ones! Also as I understand it the SEL300G does not detect this. How can this be! Surely, at commissioning the wrong rotation is a very real...
We are recommissioning a genset in a different location. It has a Basler DECs300 on it. Excites fine, good voltage control off line. As soon as we sychronise we go out on OEL Altered the hi set time but same effect. Can anyone shed light on possible causes? Other than trying to adjust the Hi...
A facililty has several old gensets plus a couple of new ones. They run them in an 'n-1' config for load.They have had several instances where if a genset trips then the others do not easily pick up the load. The fairly long delayed automatic load shedding comes into play and they loose big...
Gentlemen. I am between a supplier and a regulatory authority. The Supplier has provided a formula for the above as Tq" = Tqo" x (Xq"/Xq) using a Japanese Society formula. He says the derivation of Tq" is not mentioned in ANSI or IEEE for cylindrical rotor synch generator (air cooled 45MW)
The...
A client has a 6600kV generator and an 11kV/6600kV Dyn step up transformer. The generator has 3 neutral CTs and neutral is hard connected to earth. The 11kV synch breaker has the other set of differential CTs. Should the star point of the LV of the transformer be connected to anything, or left...
