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Stationary Load Banks

The LS Series of Outdoor Stationary Load Banks offer the most robust, high-capacity, outdoor designs in the industry. Trystar is setting the standard with intelligent operator controls, safety indication layouts, adjustable load step resolution, and ease of installation. The LS Series of Stationary products is the perfect solution for regularly scheduled testing and commissioning of mission-critical standby emergency power systems.

Built to Last Construction

The LS Series Load Banks are constructed of galvanized steel with the highest quality durable powder-coat paint finish, and external stainless steel fasteners.

All power, motor, and control connections are provided in a sealed thermostatically controlled heated compartment to limit any harmful effects of moisture and condensation. Optional Stainless Steel enclosures (304 or 316) and custom paint colors are available.

Intelligent Monitoring & Control

Trystar gives you more insight and control over your load bank. Options include standard manual control, digital control, software control, networking & more.

Standard Operator Controls Include:

  • Emergency Stop (E-Stop)
  • Illuminated Main Power On/Off Switch
  • Illuminated Blower Start/Stop Switch
  • Load Monitor Selector switch (dual voltage units)
  • Master Load ON/Off switch
  • Individual Load Step Switches

Individual fault condition smart indicators provide operator display and load disconnect during Air-Flow Failure, Overtemperature, Motor Overload, load Dump, and Wrong Voltage Applied. Don’t settle for one general fault indicator!

Advanced Control Options

Trystar offers a couple of advanced control platforms for the LS Series load bank. The Series One controller can provide the capability of remote control, advanced digital control and networking. With this control scheme, multiple load banks can be operated in parallel with a single operator control panel or software control.

Automatic Load Level Control

Engine Wet-Stacking Solved. Trystar’s optional Load Level Control provides automatic load regulation by sensing the downstream connected load and adjusting the amount of supplemental load bank steps applied.

Remote Indication and Alarm

Contact closure [form-c-type normally open and normally closed] provides user interface to your building management system for indication, detection, and alarm of “Air-Flow Failure,” “Over-Temperature”, and “Load Dump”.


PowerDyne™ Resistors are the most rugged in the industry.  The non-corrosive resistance alloy can fully handle the effects of an outdoor installation.  They are completely supported across their entire length within the air stream by stainless steel support rods which are insulated with heavy-duty, high-temperature ceramic insulators. Change in resistance is minimized by maintaining conservative resistor designs.

Cooling System

  • Integrally mounted blower motor with high-performance, direct-driven fan blade delivers the required airflow volume (CFM) for cooling resistor load elements
  • Blower motors can be wired to operate internally off the main input load bus or from an external 3-phase power source
  • Motor circuits are short-circuit protected by current-limiting fuses and thermally protected by overload relays

Operator Protection

The LS Series Load Banks come equipped with an Emergency-Stop push button allowing the operator to take the unit off-line should a critical hard-stop condition occur.  Branch circuit fuse protection provides short-circuit fault protection of all load steps eliminating the potential for catastrophic failure.  Blower On, Motor Overload, Air-Flow Failure, and Over-temperature circuits disable all load steps during a fault condition with operator visual indicators.  Dual Voltage units feature a Wrong Voltage Applied protection circuit which prevents the application of 480 VAC with the Load Voltage Selector switch in the 240 VAC position.  The Load Dump circuit provides the operator visual indication if all load steps have been removed.

Product Specifications

Power Rating

up to 3000kW

System Voltages

up to 600 VAC

Main Features

  • Outdoor Weatherproof Construction
  • Rated for continuous duty with no cool-down period
  • Highest Capacity in the smallest footprint
  • Arctic Duty solutions available for operation down to -40F

  • Slide out Resistor Case Assemblies simplifies maintenance
  • Branch circuit fusing virtually eliminates catastrophic failure
  • Intelligent Safety Circuits, Indicators and Operator Controls
  • Many options including local or remote operator control

System Frequencies

50 or 60Hz

Control Power

  • External 120 Volt AC
  • 1-phase, 60 Hertz power required for control circuit operation.  

When 120 VAC control power is not readily available, units can be provided with a control power transformer.

Digital Power Meter (optional)

A fully equipped, 3-phase Digital Power Metering System that measures a standard range of 16 load parameters. Includes RS485 (Modbus protocol) for remote reading – compatible with PC, PLC, and data loggers.

Automatic Load Dump

This circuit provides user interface provisions to the generator controls, automatic transfer switch, or building management system, to disconnect and disable all load steps from a normally closed (NC) set of auxiliary contacts.  In the event of an actual power failure, all load bank load is removed from the source under test.

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