Harminics imbalance

I suggest you look at a consulting firm that advertises expertise in the field of harmonic mitigation. They should be able to measure and analyze your system and explain clearly what your issues are and how to resolve them.

There are a lot of pseudo experts and just plain snake oil salesman in this area. I suggest looking for one that is willing to give references with contact info - insist on a reference of a customer that has dealt with harmonic problems. Actually call the references, and verify that they satisfactorily solved the problem. I'm sure you will go through more than one before you find one that has a good, credible reference.

Don't spend any more of your money until you have a good consultant on board.

Matthew

| We are operating in a building built in 1958. I am told it has 2 feeds. | We are having very much trouble with surges that are messing with newer | and more sensitive computer systems than we had in the past. We have | had a commercial electrical contractor working for some time with no | results. They have monitored the incoming power and have not been able | to show that this is a external problem. We also have 3 phase power and | equipment in the building which we are told has no effect on the | problem we are having. We found after some testing that the base ground | was suspect and that has been redone but did not change the problem. I | am hopeful of finding some one who may have an answer from their past | to such a problem. I could try to find my of a description if this does | not cover everything. There has been conversation of putting a line | conditioner on but the same conversation says that the line conditioner | will not help but the electrical contractor is at his wits end finding | the problem. HELP

There's a whole lot you did NOT describe here. I doubt anyone can give you much of an answer without knowing a lot of details. Some can probably list more things to check.

What country is this in?

What is the nature of the "2 feeds"? Are there separate systems? Same or different voltages? How are they grounded?

What kind of monitoring was done? Was it a multi-channel volts/amps on all phases, neutral, AND ground? What was the monitoring resolution?

How are the sensitive computer systems connected? Is everything on the standard voltage (e.g. 120 in US/CA/TW, 240 in UK/AU, 230 in Europe, or

What equipment is connected to the 3 phase? Motors? Blower? Fans? Elevators? Air conditioners? Who told you it has no effect?

Is there any pattern to when the failures occur? What is the weather when these failures happen (including temperature)?

What type of ground system is present?

How close is the next nearest building?

1. How do you know that "surges" are causing the problems you describe?
2. How do you know that the new computer systems are "more sensitive?"

Think about blaming the air conditioning. That's generally a good excuse too.

Your problem looks a bit like an issue I had with a factory in East Tamaki. After checking phase rotation - I thought was the most obvious, I then tested and followed back earth connections to the building. It turned out there were four different earth connection to (actual) ground. I pulled three of them out and connected them back to the one earth - problem solved. It comes back to the basic electrical practice of having one earth, otherwise you end up with potential through earths. When you've checked this I'd be inclined to do some insulation tests.

So far as conditioning is concerned I'd recommend such be connected to machines and devices as required instead on one huge conditioner for the entire building.

Does this help?

:-) Peter

Matthew Beasley wrote: