LOAD
BANKS

Branch
Circuit Fuse Protection

Powr-Rod
Load
Element

Powr-Web
Load
Element

Water-
Cooled
Elements
 

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.

Water-Cooled Elements

Water-Cooled Load Banks use specially designed, inconel sheath resistive conductors. The elements are housed inside a steel load module. The elements of each load step are protected by branch circuit fuses. Monel and bronze construction for saltwater cooling is available.
 

Powr-Rod Load Element

Simplex LBD Series Load Banks utilize the UL Recognized, “Powr-Rod" load element. Considerations of personnel safety and equipment durability dictate the use of totally enclosed load elements in a radiator airflow cooled Load Bank. The load elements are visible and within reach of personnel. They are also exposed to the weather, mechanical stresses and airborne contamination by the radiator air blast. The "Powr-Rod" element consists of a nickel-chromium resistance wire which is electrically insulated and sealed within a metallic sheath. Since the element is electrically dead on the outside, it reduces the hazard of electric shock to personnel and eliminates the danger of short circuit of the elements by foreign object penetration. The element is unaffected by rain and by airborne dirt and oil. Since the element is essentially a solid metallic tube, it is extremely rugged and will not fatigue from engine or air-blast vibrations and will not sag or stretch if overheated. The element sheath material is "incolloy," a rustproof nickel alloy with a very high temperature rating (1600°F). The “Powr-Rod" load element does not require a cool-down period.
 

 
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.


Simplex Powr-Web
Resistive Load Element 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