Click on question marks below to get answers to these frequently-asked questions.
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What do you mean by general purpose dry type electrical transformers, especially under 112.5 kva?
A general purpose transformer is just that. A transformer that can generally be used anywhere for almost any common purpose or application. It doesn’t require an electrical protective vault or special ventilation so it can be used almost anywhere. It can be indoors or outdoors with a weather shield. And it doesn’t take up a lot of room compared to liquid filled or some special purpose power transformers.
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What does “dry type” mean?
“Dry type” simply means it is cooled by normal air ventilation. The dry type transformer does not require a liquid such as oil or silicone or any other liquid to cool the electrical core and coils.
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Are there Standards or Technical Literature about electrical power dry type transformers that might be helpful?
Try these Web Sites: http://www.ecmweb.com/ar/electric_guidelines_installing_transformers_2/
and http://www.usbr.gov/power/data/fist/fist3_30/3_30_3_1.htm.
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Why separate a 112.5 kva dry type transformer from a dry type transformer larger than 112.5 kva?
Most transformers 112.5 kva and smaller are less than 600 volts on the high voltage side and the low voltage side. Yes, many transformers over 112.5 kva are less than 600 volts, but as the size gets larger, the percentage of transformers with a “high voltage winding” increases rapidly.
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What are the standard voltages of these transformers?
The dry type transformers come in all the standard voltages, 120/240 volts, 240 volts, 120/208 volts, 375 volts, 480 volts, 480/277 volts, 575 volts, and 600 volts. Three phase and single phase. Some may have a high voltage winding at 2400 volts, 3810 volts, 4160 volts, 7200 volts, 13,200 volts, 13,800 volts etc.
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What if I need a small transformer but with special requirements? What if I have special voltage requirements? Say I need a drive isolation transformer? K Factor transformer? High basic impulse level, BIL? Cast coil?
MIDWEST sells general purpose dry type transformers and any of these special purpose electrical power transformers. Speak to an Engineer in technical sales.
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What is a dry type transformer?
A dry type transformer is a voltage changing (Step-up or Step-down) or isolation device that is air cooled rather than liquid cooled. The transformer case is ventilated to allow air to flow and cool the coil (coils).
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What services are offered by MIDWEST Switchgear Division?
MIDWEST sells and rents new and reconditioned transformers. We can often find repaired, overhauled, or obsolete transformers and offer substantial savings over new units. We can recondition a transformer so that is looks and performs like new.
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What are some uses and features of these transformers?
Dry type transformers are a cost effective way to get a desired voltage not currently available. Sand cast coils are available for applications requiring low noise levels. Medium voltage dry type transformers are often used in unit substations in large commercial and industrial applications.
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Why Buy Used Transformers?
This Question comes up frequently with new customers. The answer may be obvious and may not be so obvious.
The cost of a used transformer is approximately one-half that of a new transformer.
Lead times for used transformers are about 2-3 days on average. Lead times on new transformers are considerably longer: they vary from 2-3 weeks for smaller sizes (<150 kva) to 3-4 weeks for larger sizes. The lead times may be even longer if uncommon voltages are involved, (480/380, 600/480).
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I bought a used transformer from you guys and it looked like it was brand new. It was a little 50 kva dry job. Had some of the original stickers and packaging on it. No holes in it. I’m sure it was never installed. Did we get lucky or did MIDWEST send us a new transformer instead of a used transformer by mistake? Either way, thanks but we won’t send it back.
We sell transformers that were never install, never energized, but we can not sell them as new from the manufacturer. These are transformers that we get from someone that purchased them from the manufacturer, but never used them. They’re just like new, but we do not sell them as new because we did not buy them directly from the mfg ourselves. Sometimes these transformers are called new surplus instead of used. Also, we test these transformers anyway, since they were out of our custody and care when some one else had them. So it is your good luck to get a new used transformer.
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