Howard Mobile Power Transformers User Manual

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Howard Industries, Inc.
ISO-9001 Certied
Howard Industries Mobile Power transformers are specially designed for use with mobile power systems and are the ideal choice for applica­tions requiring step-up transformation and interconnection with an electri­cal distribution grid. These rugged transformers can take all the abuse a transportable system typically receives. They are specially designed and equipped for the rental power market, with many valuable features that improve portability and increase exibility for use with different grid voltages.
Contact the factory or your local Howard Industries representative for more information about our Mobile Power transformer line and about the many custom solutions we can offer.
Ratings
Standard ratings for Mobile Power transformers have been selected to satisfy typical requirements for mobile power systems. In addition to these standard ratings, a wide range of optional ratings is available to satisfy any special customer requirement.
• Standard capacities: 45, 75, 112.5, 150, 225, 300, 500, 750, 1000, 1500, 2000, 2500, 3000, 3750, and 5000 kVA
• Standard high-voltage rating: 14400 volts delta, with taps at 13800, 13200, 12870, 12470, 12000, and 11700 volts.
Optional high-voltage ratings from
2400 through 19920 volts
• Standard low-voltage rating: 480Y/277 volts.
Optional low-voltage ratings from
120 through 600 volts
• Standard frequency: 60 Hertz. Optional frequency: 50 Hertz
Three-Phase Pad-Mounted
Mobile Power Transformers
FIGURE 1: Three-phase Mobile Power transformer
Standard Features
• Designed and manufactured in
accordance with all applicable IEEE/ANSI and NEMA standards
• Non-loadbreak high-voltage tap switch with operating handle located in the high-voltage compartment
• Externally clamped porcelain high-voltage bushings with spade terminals (live-front construction)
• Mounting provisions for lightning arresters in the high-voltage compartment
• Externally clamped epoxy or porcelain low-voltage bushings with integral spade terminals
• Removable neutral ground strap in low-voltage compartment
• Lifting provisions
• Jacking and rolling provisions
• Removable steel forklift channels
Catolog Section
91-20
• Removable terminal compartment and front sill
• Tamper resistant removable tank access cover
• Three-point door latching system with padlock provision and recessed interlocking pentahead security bolt
• Tank grounding provisions
• Welded mild steel tank construction
with mild steel terminating compartment
• Mild steel barrier between high-volt­age and low-voltage compartments
• Corrosion resistant hardware
• Recessed tank compartment
bottom
• Domed covers on tank and terminal compartment
• Electrostatically applied powder paint nish with polyurethane top­coat (ANSI 70 light gray)
Document No. 2.4.136 Revision: 0 Issued: December 2, 2011
Copyright © 2011 Howard Industries, Inc.
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Howard Industries, Inc.
Laurel, MS 39440
www.howardtransformers.com
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91-20
Mobile Power
• Oil ll/oil level plug
• Oil drain valve with sampling device
• Automatic pressure relief device
• Dial-type liquid level gauge
• Dial-type liquid temperature gauge
• Electrical grade mineral oil insulat-
ing uid with oxidation inhibitor
• Laser engraved nameplate
• Bushing designation labels
Optional Features
• Insulated interphase barriers
• Two 2.5% high-voltage taps above
and below normal voltage, or four
2.5% high-voltage taps below normal voltage, or four 2.5% taps above normal voltage, or no high­voltage taps
• Dual high-voltage rating with non­loadbreak switch handle located in the high-voltage compartment (not available in combination with high­voltage taps)
• High-voltage fuses, including internal expulsion fuses, draw-out expulsion fuses, internal backup current limiting fuses, and draw-out full-range current limiting fuses in dry-well canisters
• Internal load-break high-voltage ON/OFF switch with operating handle located in the high-voltage compartment
• Stainless steel tank and terminat­ing compartment
• Flip-top hood on terminal compartment
• Cover mounted high-capacity pres­sure relief device
• Rtemp®, silicone, or seed-based vegetable oil insulating uid
• Cooling fans with control or fan mounting provisions only
• Mounting provisions for external electricity meter
• Hexhead security bolt (pentahead standard)
• Temporary service access provision (conduit hole) in terminal compart­ment sill
• Optional topcoat paint color: ANSI 49 light gray, ANSI 61 light gray, ANSI 24 dark gray, olive green (Munsell 7GY3.25/1.5), or white
• Tank grounding connectors
Unit Substation Designs
In addition to the standard pad­mounted compartmental design previously described, Mobile Power transformers can also be supplied in a unit substation design (Figure 2), available with a variety of different high-voltage and low­voltage termination interfaces, such as full-height anges, throats, or air terminal compartments. Substation transformers are available in capacities through 10,000 kVA, with high-voltage ratings up to 69 kV.
Figure 2: Typical unit substation transformer.
Document No. 2.4.136 Revision: 0 Issued: December 2, 2011
Mobile Power Transformers
Catalog Section 91-20
Document 2.4.136, Revision 0, December 2, 2011
Copyright © 2011 Howard Industries, Inc.
Laurel, Mississippi
Telephone: 601-425-3151
Fax: 601-649-8090
Web: howardtransformers.com
Copyright © 2011 Howard Industries, Inc.
2
www.howardtransformers.com
Howard Industries, Inc.
Laurel, MS 39440
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