The geared variable speed coupling combines the hydro dynamic coupling and Mechanical Gear in one compact unit.
The geared variable speed coupling controls the speed of the driven machine precisely, quickly.
Geared Variable Speed Coupling
Uses:
It is used to control the speed of the Driven Machine,Vary the power transmitted Reduce the power consumption, Increases the productivity of operation. Motor can start at no load
Design and function:
*The hydrodynamic geared coupling consist of double helical gear integrated in a housing with a split horizontal body.
*The gear box is located before the hydrodynamica coupling.
*In hydrodynamic coupling there are two wheels, pump wheel and turbine wheel. pump wheel is connected to the drive machine. and the turbine wheel is connected to the driven machine.
*The pump wheel rotates at constant motor speed and the turbine wheel rotates at variable speed.
*Using the hydro dynamic principle the fluid is transmitted from the pump wheel to the turbine wheel at variable output speed.
*The scoop varies the coupling filling. The filling amount determines the power transmitted and the speed of the driven machine.
*An actuator varies the speed of the scoop tube, in this way speed can be controlled.
*Working oil is supplied to the hydrodynamic coupling for varying the speed
*lube oil is supplied to the gear box.
*working and lube oil circuits are seperate.
The actuator is Electro hydraulic actuator for quick and precision operation of the scoop. A simple 4-20 MA is requires to control the scoop position.
The motor will start with no load conditions and smoothly accelerate even with machines with large moment of inertia. This happens because the hydrodynamic coupling is empty during the motor starting, so it seperates the motor from the driven machine so that the motor runs at no load condition.
starting the motor at no load conditions are important for equipments having large moment of inertia or with processes with initially large load.