LD-RT Series Radiator Air Cooled Load Banks 5 kW - 400 kW

Roof Top Mounted Style for Sound Attenuated Enclosures

Load Banks Direct, LLC is a leading manufacturer of high-capacity Load Banks. The LD-RT series of roof top mounted Load Banks offers simple, easy to mount, economical solution for providing diesel generators with a supplemental load to minimize the effects of wet-stacking during operation under lightly loaded conditions. LBD is setting the standard with intelligent operator controls, safety indication layouts, and adjustable load step resolution. The LD-RT Series provides a cost-effective solution for regularly scheduled maintenance testing of mission-critical standby emergency power generators. 
  • Specifically designed for rooftop mounting on a sound attenuated GenSet enclosure with vertical exhaust 
  • Sized to match exhaust area
  • Separate wall mounted Operator Control Panel
  • Outdoor design with stainless steel top
  • Cost-effective solution for routine generator testing
  • Reduce engine wet-stacking | Improve engine emissions
  • Branch circuit fusing virtually eliminates catastrophic failure
  • Intelligent Safety Circuits, Indicators, and Operator Controls

LD RT 1w

Construction  |  Built to Last

LD-RT Series of roof mounted load banks come standard with powder-coated galvanized steel frames, stainless steel tops and stainless steel hardware. Don’t settle for unpainted frames or pay a premium for a powder coated enclosure. The roof top frame is sized to match the exhaust opening and can be designed to provide an overhang for convenient bottom conduit entry. The frame houses the resistor load elements as well as an integral side-enclosure for customer load connections, load step contactors, controls and fusing. The operator controls are provided in a separate NEMA 4 enclosure for remote installation.

LBD-PowerDyne™  Load Elements | When Quality Matters

PowerDyne™ Resistors are the most rugged in the industry.   They are fully 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.    

KW Load Capacity

The LD-RT Series of Roof Top mounted load banks are available in any size range from 5 KW through 400 KW at any available single phase and three phase Voltage (up to 600 Volts AC).  They are intended for use as a supplemental load to the generator set and are typically sized at 50% of the generator KW rating.  


The Load Bank is directly mounted to the exhaust opening of an enclosed GenSet. The engine radiator cooling fan delivers the required airflow volume (CFM) for cooling the resistor load elements. The load bank does not have its own cooling and relies on the radiator fan to operate properly.

Control Power  

An external 120 Volt AC, single phase, 60 Hertz power source is necessary for control circuit operation.  When 120 VAC control power is not readily available, units can be provided with a control power transformer.  
Operator Protection | When Safety Matters
LD-RT Series of roof top (horizontally mounted) Load Banks come equipped with a remote Operator Control Panel.  The Emergency-Stop push button allows 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.  Over-temperature circuits disable all load steps during a fault condition with illuminated indicator.  The Load Dump circuit provides the operator visual indication if all load steps have been removed.
Operator Controls
  • Illuminated Main Power On/Off switch
  • Master Load On/Off switch
  • Individual Load Step Switches
  • Fault condition smart indicators provide operator display and load disconnect during Overtemperature, and Load Dump

LDRT Side View wLDRT Top View w

Automatic Load Dump 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.

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 “Over-Temperature”, and “Load Dump”.

LD-RT Series Resources

Outline Drawing LD-RT Series

Instruction Manual LD Series

Sales Brochure LD-RT Series

Automatic Load Step Controller


Radiator Duct Mounted Load Bank Specification

Radiator Duct Mounted Load Bank with Automatic Load Leveling Control Specification

Radiator Duct Mounted Load Bank with Automatic ReGen Power Absorption Control Specification

Your Complete Solutions Provider | When Testing Matters

LBD’s complete line of portable and stationary Load Bank products offers industry exclusive load testing solutions for generator set dealer/distributor networks, service arms, rental companies, end users, and original equipment manufacturers of generator sets, UPS systems, turbines, fuel cells, wind power,  and battery systems.  LBD is your factory-direct complete solutions partner.