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Hello The reason we cannot change the tap is because these tools go all over the world. And we want to maintain some commonality and not change taps all the time to suit our needs. They are fixed at a certain tap. Small transformers have poor regulation. The problem I am having is that this...

We are having a trip problem at site. I suspect it is voltage as I raise the tap, the problem goes away. I cannot raise the tap to solve the problem. So for a load length of 60 feet for the 19kva load,0.75 pf, 208v ( transformer is 480/208v) what is the correct cable size? The transformer is...

I have transformer 45kva. My load is 19kva, 0.8pf 208V and is a rectifier. The transformer regulation at unity pf is 5.5%. What size of conductor must I provide to feed the load ? Other laods are about 10kva, combintaion of single phase and 3 phase. Pl assume some unbalance of 15% due to single...

Hello The breaker is not tripping but the power limiter safety device in the tool is tripping. Looking at the power waveform that is drawn into the tool shows power spikes and this happens only during higher power draw close to 14.7kw When I hooked this device to 45kva transformer it starts...

I have come across an interesting unresloved problem. A gas cleaner keeps tripping on or around 80% loading. The transformer that feeds this unit is 40kva and the max load kw is around 15kw. The waveform from the unit on the input to the equipment shows chopped waveform on the AC. THere is...

This is to supply 120v to some instruments which will not tolerate a ground. And since this goes to some other cabinet, I would like to add a GFCI. Any ideas?

Apologies. I did not read the link fully. The requirement is for a ungrounded transformer. no grounds anywhere. Is there any means where we can detect a ground in an isolaed system?

http://bg.ecmweb.com/ar/electric_replacing_wire_ungrounded Pl see this above. Is this an acceptacle solution to this problem ? thanks

Hello I am designing a 120 v circuit that has an isolation (1:1)transformer in it. On the secondary 120V circuit, I would like to install a GFCI breaker for 5mA. But all the breakers I looked at needs a grounded system while my transformer secondary needs to be ungrounded and floating. How can...

I will do tha following regarding this transformer: 1. Meggar the transformer with an appropriate meggar. This will have the correct voltage. Note the insulation resistance. If more than 200Mohms, we can start. 2. Test the oil. Take a sample and do a dielectric test. 3. Clean all the insulators...

Thanks for all the information. You have talked about AC circuits. How about DC circuit power source ? i am using 24VDC power and not AC. Will this make any difference ? thanks

Thanks for all these great responses. Aprreciate. but is there going to be problems assocaited with cable capacitances? How would a long cable capcacitance affect ? I heard form some of the messages that the contactor or relay fails to operate due to cable capacitance. In my case what is the...

Thanks for all the information. Yes I agree it is better to go for the pull wire system. But due to reasons beyond my control I will have to use this system. All switches are Fail safe. I have 3 relays that are using this circuit and they are small. May be 1 amp at the most. Will it work for 1...

I have 30 switches in series on a long belt conveyor that runs more than 500 feet. The total length of the circuit is 556 feet, 2 wire, 24vdc, 5 amp supply. I am using 18AWG wires and any of these 30 switches can be activated to turn off the motor. Since this is a critical function circuit with...

Is PSCAD the same as EMTP or atp ? How much does this cost? thanks

thanks folks. You have opened my eyes, Appreciate.

Pl give some sites where they give instructions for TACS. This outreach program, Is it available as a distance education? Pl pass on some information to help tutor myself thanks

I have designed a AC cabinet with a transformer of 2 kva inside. 208/120. The secondary side neutral is grounded and bonded as this is seperately derived system. The feed from the transformer leaves the cabinet and goes to another cabinet to distribute the 120v power. The ground wire is also...

I have always wanted to learn ATP. i have dreams of doing a transformer inrush study, stabilty studies, motor starting study, voltage collapse study etc. it will be pure fun to watch these things. But I hear that learning EMTP or ATP can be quite a task ? or I am imagining this? If you folks...

Hi Is this normal to have a corner grounded system ? The 6 volts may be the voltage drop due to IR. But that would mean that further you go, the ground will be displaced. murli