ENGINEERING SPECIFICATION
FOR HORIZONTAL
OUTDOOR RESISTIVE LOAD BANK
(750, 1000 AND 1250KW)
1.0SCOPE
1.1This specification contains the minimum requirements for the design, manufacture and testing of an outdoor weatherproof resistive load bank.
1.2The load bank is required for periodic exercising and testing of the standby emergency power source. The load bank shall be permanently mounted in a weatherproof enclosure, forced air cooled with a remotely mounted control panel.
1.3This specification shall apply if the load bank is supplied to the purchaser or as a part of other equipment.
1.4Should the vendor take exception to any part of this specification, it shall be stated in the bid with item number referenced.
2.0STANDARDS
2.1The equipment covered by this specification shall be designed as it applies with the latest standard of NEMA, NEC, ISO and ANSI standards.
3.0 |
RATINGS |
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3.1 |
The total capacity of the load bank shall be______KW at________Volts, 3 Phase. 60 Hertz, with_______Amps per |
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Phase with Unity Power Factor with 50KW minimum load step resolution. |
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KW |
VOLTS |
AMPS/PHASE |
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750 |
480 |
901 |
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1000 |
480 |
1202 |
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1250 |
480 |
1502 |
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3.2 |
The duty cycle shall be continuous and the load bank shall operate in an ambient temperature of -28°C to 49°C |
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(-20°F to 120°F). |
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4.0CONSTRUCTION
4.1The load bank shall be constructed of heavy gauge aluminized steel per ASTM A463 or coated mild steel that meets or exceeds physical and chemical performance of polyurethane enamel coatings. Galvanized steel has a low corrosion threshold and shall not be used for exterior load bank construction.
4.2The main input load bus, load step relays, fuses and blower/control relays shall be located within the load bank enclosure. A thermostatically controlled heater shall be located within the control section to protect control devices from the effects of moisture and condensation.
4.3The load bank shall be outdoor weatherproof construction. All exterior fasteners shall be stainless steel. The load bank shall include forklift channels in the base for lifting.
4.4For maximum protection and reliability in an outdoor environment, airflow shall be horizontal screened air intake and fixed louver shall be provided at the exhaust.
4.5The exterior of the load bank shall be painted with polyurethane enamel paint at a minimum 2 MILS dry film thickness with a spatter finish.
4.6Load elements shall be contained in one or more resistor cases or trays. Each can be removed in their entirety as a unit if service becomes necessary.
5.0RESISTIVE LOAD ELEMENTS
5.1Load elements shall be Avtron Helidyne™, helically wound chromium alloy de-rated to operate at approximately ½ of maximum continuous rating of the wire. Elements must be fully supported across the entire length within the air stream by segmented ceramic insulators on a stainless steel rod. Element supports will be designed that should a wire break, it will not short to adjacent conductors or to ground.
8/2011-RevA (K575A)
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