LOAD
BANKS

Powr-Web
Load
Element

Inductive
Load
Elements

Branch
Circuit Fuse Protection
 

 

 
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
 

Inductive Load Elements

These discrete iron-core load elements are non-saturable, air gap calibrated, air cooled devices and field replaceable. Elements may have a temperature sensor embedded in the windings used to detect element overheating and activate the malfunction detection system which disconnects the load elements and activates an alarm. Standard elements are varnish coated; epoxy coatings are available for severe environments.

Specifications
Tolerance: 5%
Maximum Harmonic Distortion: 1%
Power Factor: .05
Insulation: 220°C
Cooling: Air

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.