Power Transformers Blog – Expert Safety and Usage Info

Buy Dry Type Transformers

Some common misconceptions about Transformers:

Transformers can easily be backfed. Yes and No. Transformers cannot always be reversed willy nilly. Due to cost control some manufacturers design transformers which do not allow the primary and secondary sides to be swapped. Contact your favorite electrical engineering office for your case specifics.

Dry type transformer are designs of convenience and can be stuck in a corner or in any confined space with no problem. False. Dry type transformers are designed for indoor use and are air cooled. They require an adequate supply of moving cooler air to operate within their proper temperature range. If dry type transformers are located in indoor substations, the substations should be properly vented to allow good cooler ambient air flow to circulate in and about the transformer.

MIDWEST was challenged by a technical skeptic to give him just one example of a large old oil filled transformer that obviously outlasted its useful life expectancy.  Apparently he got into a heated argument with some old timer electricians who claimed they trusted the old transformers a lot more than new stuff they had seen.  It may not be wise to argue with experienced electricians.  They have ways to argue with enthusiasm and sometimes expressions that leave little doubt as to the strength of their convictions.  And they have real world experience, usually a good trump card. 

 MIDWEST gave him the example of two 2000 Kva old substation transformers built in the 1950s that have been running at 107% full load for the last 20 years.  These are not rebuilt or reconditioned transformers.  But they are pretty inefficient and about 3 times as large as a new oil transformer the same kva.  MIDWST is not suggesting old transformers are better than new.  But, be careful when buying new transformers.  Specify quality and reliability, or you may get cheap and disposable.

10.       Even if they don’t know the song, used transformers hum along as if they did.

9.         Used transformers require no burn in period. They are good to put in service right out of the crate. 

8.         Used transformers are very green. The carbon footprint you save may very well be your own.

7.         Buying used transformers helps create jobs.  With the money saved, your company will have more resources to put into that next great business expansion.

6.         Buying used transformers puts you in the drivers seat ─ of your golf cart that is. As your boss will no doubt give you the afternoon off after saving the company money.

5.         Our used transformers meet national testing standards.

4.         Our used transformers are readily available. Lead times for new transformers can run into weeks if not months. Your used transformer can be in your hands as soon as preparation time allows. 

3.         Our used transformers come in designer colors. Check out our beautiful array of designer gray colors.

2.         You may choose to rent one of our used transformers to serve as a temporary power solution.

1.         And the number one reason to buy used transformers is it saves money, up to 70% off the cost of new.

PCB (polychlorinated biphenyl), that little man made molecule that was so good it just would not go away, that is, without the help of man.  The problem with PCB is also its strength. Unlike many things on the planet, PCB is a highly inert molecule meaning it does not easily combine with other molecules in nature. Drop it off in a field somewhere, come back in 100 years and it will still be there waiting for you in pretty much the same shape you left it. How many things can you say that about? From approximately 1930 through 1979 PCB was used as a dielectric fluid and coolant in old electrical transformers and capacitors. Since 1979 Federal register regulation 40 CFR 761 has regulated the manufacturing, processing, distribution and use of PCB’s in Commerce.  Today the use of PCB in existing electrical devices has all but disappeared. Today MIDWEST is actually surprised when we find a PCB transformer. 

One popular misconception was that old transformers created PCB as a by product of the electro magnetic process. This myth grew from the fact that many mineral oil filled transformers were found to contain low levels of PCB in their oil. The truth of the matter is not that mystical. The oil in these transformers became cross contaminated with PCB from PCB contaminated pumping equipment used to recondition the oil in these units in the days before PCB was regulated.