Acme Catalog

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M e d i u m V o l t a g e T r a n s f o r m e r s

Medium Voltage Transformers, 2.5–5kV Class

Medium voltage dry-type transformers are used to step down incoming high voltage power to utilization voltages for residential,

commercial, institutional and industrial applications. Offering many advantages over liquid-filled transformers, they are ideally suit-

ed for indoor application close to the load for more efficient distribution of power at lower operating costs.

Acme Electric medium voltage dry-type transformers are air-cooled by natural convection, eliminating the principal hazards asso-

ciated with liquid-filled transformers as well as the need for expensive fireproof vaults and venting systems for toxic gas. They are

generally smaller, lighter, and easier to maintain than liquid-filled transformers, requiring only occasional cleaning and inspection.

They are encased in a ventilated steel enclosure with no exposed live parts, making them ideal for installation in buildings such as

hospitals, theaters, schools, office buildings, and factories.

Because Acme Electric gives close attention to detail and workmanship throughout design, production, and inspection, our medi-

um voltage dry-type transformers are designed for economical, trouble-free service for a life expectancy of 25 years or more. In

particular, we optimize the design for BIL levels, short circuit strength, losses, temperature rise, corona-free operation, and low

sound levels so that there is no need to over-specify to ensure quality and long, economical performance.

DOE 2016 and CSA C802.2

Our new line of medium voltage transformers not only meets but exceeds the new, more stringent DOE 2016 Energy Efficiency

Standards U.S. DOE 10 CFR Part 431Subpart K, and Canadian Energy Efficiency Regulations SOR/94-651.

UL Listed

All units are cUL Listed per UL-1562 and CSA C22.2 No. 47.

Basic Impulse Level

One of the most important considerations in the specification and design of medium voltage dry type transformers is the basic

impulse level (BIL). This is the ability of the transformer to withstand impulse voltages impressed upon it by switching surges or

lightning. BIL ratings are per IEEE Std C57.12.01.

Corona

Corona is the ionization of air surrounding a high voltage electrode. Corona discharge can reduce transformer life by

1.Gradually breaking down the chemistry of insulation system

2.Forming streamers or eroding tracks on the insulation or insulators, causing subsequent flashover

3.Reducing the transformer BIL level

Corona-free operation is a priority in all Acme Electric transformer designs. Through a combination of air spacing, insulating mate-

rials, and semiconducting tape, all of our medium voltage dry-type transformers have corona extinction levels that exceed their

operating voltage level.