Philadelphia Gear

100% Lock-Up. 0% Fixed-Slip Losses.


Philadelphia Gear’s Synchrotorque® line of hydroviscous clutches operates on the principle of shearing an oil film to transmit torque. This hydroviscous effect transmits torque in proportion to a variable clamping force. For unrestrained loads, the higher the clamping force, the faster the output speed. The input drive plates function as the driver. The output friction discs are faced with a suitably grooved resilient material and act as a driven member.

Precisely controlled clamping pressure between input drive plates and output friction discs allows virtually infinite speed control right up to 100% of input speed. This simple phenomenon, based on hydrodynamic bearing principles, is the basis for controlled torque transmission in the Synchrotorque hydroviscous clutch.

  • Works for 100 HP to 20,000 HP applications
  • Range of sizes for a variety of mounting configurations
  • Output speed equals 100% of input speed to maximize energy efficiency
  • No fixed-slip losses
  • Can transmit torque in either direction
  • Can remain running while disconnected from load
  • Maximizes torque transfer in compact space
  • Protects drivetrain from excessive loads with automatic torque limiting feature
  • Appropriate for adverse environments


Synchrotorque ISO