Recent content by pqsl

Thank to all for sharing valuable information. Practical information on what works and what does not in permafrost is scarce. I will follow up all your suggestions.

Thanks sslobodan. My concern is grounding of land based systems north of arctic circle. 1 - Do standard methods of ground resistance measurements apply on existing installations? 2 - What is the procedure to measure ground resistivity in order to use it in ground grid design calculations...

Yes it is measurements in "Arctic" not covered in tsis forum.

Hi, I am looking for guidelines / information or any help related to ground resistance measurements and also ground resistivity measurements. Looks like this topic was not discussed in this forum. Any experts on this topic?

I am looking for industrial thermostat to be able to sense ambient air temperature less than 20Deg. F (accuracy is not important) with dry NO or NC contacts. There is no problem to find 30Deg. F. Any suggestions here without using 4-20ma or external power?

Thanks itsmoked. http://i1.tinypic.com/2vsiuiw.jpg http://i1.tinypic.com/4i4mowp.jpg http://i6.tinypic.com/2lkfvqd.jpg http://i10.tinypic.com/2hrialw.jpg If you built this. Please let us know how it worked out for you. I will also be intrested to hear any comments on this design.

faulkma, No problem there. But I do know how to send or post the file. Maybe some one in this forum knows how.

Did you have a batch of these power supplies failing during short period of time and then failures stopped? Did you do any investigations on Power supplies? Any surge suppressors on the 120/208V? Any UPS power supplies? Our client had this happening 2 years ago. 10 PS in less than 1 month. Power...

I am looking for another way to see if AutoCad environment can display values in base 10 logarithmic scales to use with Logarithmic graphs. I wrote small AutoLisp program that actually works but that was in 1994. Does anyone know if there is another way?

An inexpensive solution was described and explained in October 2, 1975 issue of "Plant Engineering". Components you need are: 1 - Variable transformer (could be omitted) 1 - Step-up transformer 2 - Fixed value capacitors 2 - Variable resistors or rheostats Article was written by Robert C. Davey...

Which TVSS is appropriate to use on 600/347V MCC? Transformer feeding this MCC is has neutral solidly grounded at MCC. Neutral bus is not available to connect TVSS. Ground bus is available to connect TVSS. 1. Delta TVSS is connected to the above MCC. What are the advantages and...

To get high accuracy for P(out)/P(in) method high accuracy current sensors are necessary say 0.01% or less and that might be difficult with any conventional current sensors. Therefore P(out)/P(in is) inappropriate method to use with equipment introducing large error. Even 0.5% accuracy will add...

Another aproach is in this link http://www.hvtechnologies.com/download/HIGHVOLT/7-5-1e.pdf but it looks like expensive solution comparing to Voltage and Current difference losses neasurement method.

One explanation might be that the source is low impedance. Another is that maybe instrument is not sampling simultaneously voltage and current. Is this delta system? Is Va actually Va-b?

Measure V thd phase to neutral - should not be more than 5% (or less hospitals gaming) Measure largest harmonic – should not be more than 3% Measure phase I(rms) - should be not more than conductor rating. Measure Phase I(thd) Measure Neutral I(rms) – should be not more than neutral rating...