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TORQUE CONTROL

Ultra-smooth starts and linear stops

The first Emotron softstarter was launched in 1983. We introduced the technique of torque control to the market in 1999, offering further reduced mechanical and hydraulic stress as well as constant acceleration and deceleration rates.

Ultra-smooth starts and linear stops

The torque control reduces start currents by up to 30% more than when using a softstarter with a pre-defined voltage ramp. This minimizes mechanical stress and allows for smaller fuses and less expensive cables. The torque control also ensures linear stops to prevent water hammer in pump applications without costly motor-controlled valves. The deceleration ramp starts at the motor load torque point and ensures a linear ramp at all pump loads.

Emotron torque control reduces the start current by up to 30% more than conventional softstarters.

 

Control algorithm maintains constant torque

The logic-based torque ramp technology uses a control algorithm to maintain constant acceleration and deceleration torque. Motor voltage, motor flux, current and voltage zero-crossing are used to determine the torque and power factor. The Emotron softstarter uses the data to continuously calculate actual shaft torque. Torque ramps can be configured for variable or constant torque loads. Square torque control can be used for pumps and fans.

 

Torque increased according to timed ramp

The torque controller generates a desired motor torque using the entered initial torque, end torque and torque ramp time. It then controls the thyristor firing on the basis of actual versus desired motor torque. The motor torque is increased according to a timed ramp and is no longer strictly dependent on an applied motor voltage or the torque/speed characteristics of the specific motor. No external motor speed feedback is required.