Mercury Stationary Load Banks
Mercury
50-150KW
Low to medium capacity load testing of generators, periodic reliability exercise of standby generators, regenerative power absorption of inertial motors with reverse power protection of generators and other Load Bank applications are achieved with these Load Banks.
The Mercury Load Bank is single or dual voltage suitable for all common 60 and 50 hertz voltages up to 600V.
Features
Master load toggle switch and load step toggle switches
Self-contained load and control
system
Utilizes the proven Simplex “Powr-Web” load element
Branch circuit fuse protection of load elements
Comprehensive overload, short circuit and malfunction protection
Color coded and numbered wiring; power wiring 150°C
Plated bus bar
Modular enclosure design with separate and isolated control and
power sections
Slide-out, tray mounted load elements
UL Listed
Capacity 50-150KW; Resistive, 1.0 p.f. Voltage All common 3-phase 60 and 50 Hz voltages: 60 Hertz: 208V, 220V, 240V, 416V, 440V, 450V, 460V, 480V, 575V, 600V 50 Hertz: 190V, 200V, 208V, 380V, 400V, 416V Frequency 50, 60 Hertz Load Steps 50 KW resolution standard 1-5-10-25KW resolution available Fan/Control Internal, from load bus. Control circuits at 120V via transformer. The cooling fan operates at 3-phase line voltage. Load control circuits and fan motor control operate at 120V. Control circuits are fused. Control circuit fuses are 100,000 A.I.C., 600V rated. External, 480/240V, supply for humidity controller, when ordered. Cooling Forced air, vertical airflow, top exhaust. 3-phase, TEFC motor driving cast aluminum fan blade. Circuit breaker combination motor starter. Airflow 2,000 CFM Duty Cycle Continuous Dimensions 43"W x 52.887"D x 55.88"H Sales Bulletin Dimensions and Key Features Diagram Stationary Load Banks: Applications and General Specifications, Features and Options, and Engineer’s Specifications |
Powr-Web Load
Element
Simplex Load Banks utilize the
UL Recognized, “Powr-Web” load element. The “Powr-Web”
is an advanced design, air-cooled power resistor specifically
designed for application to load bank systems. The “Powr-Web”
is conservatively operated at half the maximum temperature rating
of the alloy and features a short-circuit-safe design based on
continuous mechanical support of the resistor by high temperature,
ceramic clad stainless steel rods. The “Power Webs”
are assembled into discrete trays which are assembled in a vertical
“stack.” Each tray in the “stack” is independently
serviceable without disturbing adjacent trays.
Ratings
3333W at 120V
4170W at 139V
8333 watt 240/480V
16,777 watt at 480V
Specifications
Alloy: FeCrAl
Max. continuous temp. rating: 1920°F
Maximum operating temperature as applied in Load Bank: 1080°
F
Cool down time from operating to ambient temperature: 10 seconds
Construction
Calibrated to specific
ohm value
Welded lugs on each end
All load elements are continuously supported by vibration resistant,
ceramic clad, stainless steel throughrods
Branch Circuit Fuse Protection
The load of a Resistive Load Bank consists of a dense array of open, uninsulated power resistors mounted within a cooling air stream. Since the elements are electrically live, it is possible for a foreign object to penetrate the element array and create a short circuit of adjacent elements or a short to ground. Since the elements are densely packed, it is possible for a short circuit, once started, to rapidly propagate through the entire element array. As a Load Bank represents a relatively large amount of power concentrated within a relatively small volume, a self-propagating, cascading short circuit would have catastrophic results.
Simplex virtually eliminates
the dangers of short circuit through the use of branch circuit
fuse protection of the load elements. Per NEC 110-10, protective
devices shall clear a fault without “extensive damage”
to the circuit components. A Simplex Load Bank is divided into
branch circuits of not more than 50 KW each.
Simplex “Powr-Web” open wire, helically wound, chromium alloy, thermally derated to 60%. 5% tolerance, 2% balance, .995 p.f.
UL Recognized.
Load Control
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.
System Protection
Fan failure, high exhaust temperature, high intake temperature; lockout and alarm.
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 of the Load Bank. 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.
150°C insulated; color coded.
Control Wiring
105°C, color coded and/or numbered.
Temperature
Maximum ambient temperature: 120°F
Exhaust rise: 150°F
(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.)
Power Connection
Plated bus bar within an oversize terminal junction box.
