The power source is three single phase pole mount type transformers. 50 KVA 4160(2400) primary wired in Wye and 240(120) secondary in Delta. The mid tap of "A" phase is grounded making a grounded Delta. A and C phase are ~124v to ground and B phase reads about 225v to ground. They all...
This is for my employer. The problem is we have had two motors on two separate pumps burn up in the past week. They were old so it might have been thier time. I just wanted to make sure it was not the power source.
I have a 5hp single phase 240v AC motor in a prosessor. I do not have the capacity for the whole thing to be supplied by a normal single phase 240v supply. I do however have grounded Delta three phase at 240v L-L. The mid tap of A phase is grounded giving the ability to pull single phase...
This is kinda difficult to explain. The easiest way to look at it is you don't want the inductance of the generator and the transformer to be exactly the same. There is a slight capacitive effect on a transformer and you don't want a resonance between the generator and Transformer. This can...
I hope I can clear all of these up. First usually in Xfrmer testing you use 180hz (used to use 400hz) to lower the magnetizing reactants as was said. You need to use a solid state power supply or a special 180 hz generator. If using the generator you need the shunt reactor for control of...
My company is a power and distribution transformer manufacturer. Currently we have a Voltech PM3000 power analyzer. It is in need of being replaced since it reads ~125mA under no load on channel two. It is over 10 years old and is no longer supported by voltech since replacement cards are no...
I understand all of your concerns and they have already been considered. The actualy device and relay are in an explosion proof enclosure. The problem lies in that the switch that controls the relay is not and cannot be. The main reason for this is to prevent the contacts of the switch from...
Unfortuntly I can't tell you too much about what we use it for. I can tell you the main purpose for it is to prevent a flashover of the relay contacts when they are tripped. This is used in a Hazardous environment so arcing is not only bad for the contacts but could be very dangerous. This is...
Ok I got another question. I am looking over the spec sheets and I am having a hard time picking out what voltage to go with. The circuit will have 125 bolts DC. A couple of sources I found say to go 10% over rated. This would mean 137.5 volts DC. That seems a little close to me. Also I...
Thanks for the Information. I downloaded some spec sheets already and I see a couple that should work. I do not have any specs really on the Voltraps. Its one of those things where we have used them for years and years and noone knows anything about them. Its only now that someone brought it...
My company Currently has been using a device called a "Voltrap". From what I understand it is a bi-directional Selenium Diode. We use them in hazardous duty control cabinets to prevent a trasient voltage spike or flashover due to the inductive kick of a relay coil. These are getting very hard to...
Yes I believe that's how that works as the temp rises the stay loss goes down.
I understand that PU is the constant for the Per unit change of core loss per one deg C. I think that is from ANSI std C57.12.90 if you want to check it out.
For the Core Loss I was under the assumption that is was also tested at 22 deg and I corrected it to 80. If it was alreayd corrected then just add it in as it is. The ANSI formula for correction is 1+ PU * (Pt-Tt) = corr. factor
Where PU = 0.00065
Tt = perf temp
Pt =...
