Simplex “Powr-Web” open wire, helically wound, chromium alloy, thermally derated to 60%. 5% tolerance, 2% balance, .995 p.f.
Branch circuit contactors, each 50 KW step. Contactors have enclosed silver surfaced contacts, 120V coils; electrically operated and electrically held.
Element Circuit Protection
Branch circuit fuses, each 50KW branch circuit, 70A, 200kAIC, current limiting type.
Maximum ambient temperature: 125°F
Exhaust rise: RISE = KW X 3000/CFM (note: as airflow is not laminar, exhaust air temperatures are not equal at all points at the plane of air exhaust. Some parcels of air may reach approximately 575°F before mixing.)
Fan failure, high exhaust temperature, high intake temperature; lockout and alarm.
Modular enclosure consists of three parts:
1. Type 3R rainproof power section including load elements and cooling fan
2. Type 3R control section, thermally and electrically isolated from power section
3. Exhaust hood. Mounts atop power section. Vertical flow with rain separators. Hood may be deleted and a duct flange provided for indoor applications where air is exhausted through a duct to the outdoors.
All panels for access to serviceable components are hinged doors with stainless steel hinges and lockable latches. All exterior fasteners are stainless steel.
The Load Bank enclosure is of double wall construction for cool exterior and thermal isolation of the load elements. Cooling airflow through the enclosure is vertical with cold air intake at the bottom and hot air exhaust out the top. Intake and exhaust openings are screened. All parts of the enclosure are abrasive blasted or chemically etched, primed and finished with a color as specified. The exhaust hood which is exposed to high air temperatures is unpainted galvanized steel.