Joy SR (Switched Reluctance) Hybrid Drive highlights:


  • High energy efficiency
  • Evenly distributed loads
  • No commutator or brushes, making the motors almost maintenance free
  • Low inertia for higher speed capability and quicker dynamic response


  • Simple and robust electronic controls
  • Complete drive in one unit
  • Modular design

Rotor/stator design means increased torque

The Joy SR Hybrid Drive system design ensures that there are always rotor lobes approaching or departing fixed stator coils, resulting in increased torque.

Rotor highlights:

  • Less impact stress on gearing and high torque-to-inertia ratio means faster response
  • Lower switching frequency as compared to AC systems, resulting in longer power electronics and motor insulation life
  • Simple rugged design made up of a stack of electrical steel laminations
  • No windings, rotor bars, magnets, or contact of any kind
  • Cool running, since losses are concentrated in the stator

Stator highlights:

  • Short end turns permit very high torque/volume ratio for an electric drive
  • Independently wound coils have no overlap areas
  • Good thermal management since losses are easily dissipated though the outer circumference

Used on multiple product lines

Hybrid shovels

The Joy SR Hybrid Drive is used on our 2650CX hybrid shovel in the following key areas:

  • Hoist
  • Crowd
  • Swing

Generation 2 surface wheel loaders

Outstanding fuel efficiency – in some cases up to 45% less fuel consumption than comparably sized mechanical drive wheel loaders – is the result of our exclusive Joy SR Hybrid Drive system.

Utilizing proven switched reluctance technology, the Joy SR Hybrid Drive system allows power generation that is fully regenerative, resulting in very efficient wheel loader operation. During braking or retarding, electrical motors become generators and feed power back into the generator connected to the engine.  The Joy SR Hybrid Drive system allows for 100% capture and utilization of all braking energy during the loading cycle. Major components of the system include power electronics, motor/generator, control system, and gear train.

Designed to save time and money
  • Reduced fuel consumption during braking or regenerative mode
  • Engine operation at a constant-rated RPM
  • High-torque capability down to and including zero speed with full control
  • Inherent low center of gravity and superior stability
  • Reduced operator fatigue and quicker cycle times
  • Significantly quicker response for improved traction control and reduced time slip for extended tire wear
  • Best-in-class horsepower-to-weight ratio
Designed to outperform the competition

Unlike competitor’s machines that require acceleration and deceleration through the engine RPM range (with gear changes) during the loading cycle in order to follow the engine torque curve, P&H wheel loaders have:

  • No power-robbing torque converter
  • No three-speed transmission
  • No transfer cases
  • No differentials
  • No power-transferring universal joints

This means far less fluids on board, resulting in greater productivity, lower maintenance costs, and superior reliability.

Hybrid loaders

The Joy SR Hybrid Drive system on our Joy 18HD and 22HD hybrid loaders (LHD) features the KESS (Kinetic Energy Storage System) which acts as a flywheel to store energy that is recaptured during motions like braking. The reduced diesel emissions and reduced heat are critical factors in underground mining. 

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