Electronic soft starter FEAS GmbH
0,2 - 4 KW

Application
The softstarter is an electronic starter for AC-motors of the squirrel cage winding with slip-ring rotor constructional type. The function of a softstarter is to allow AC-motors to accelerate smoothly up to nominal speed, whereby the ohmic resistance has been replaced by a low-loss, bi-directional power control semiconductor. The motor ist connected up so that the electronic resistor is in series with one of the three supply wires.

Functional principle
When the motor starts up, the softstarter automaticly switches the series
resistor to a preselectable maximum value. In this way, one of the stator windings will receive a reduced voltage and therefor a reduced current while the other two receive the full voltage supply.
Through this manipulation, the otherwise constant and perfectly circular torque chracteristics are changed to an ellipse. The motor will run up slowly from stationary up to its nominal speed. While the motor is accelerating, the electronic series resistance is continuosly reduced in value, and when the nominal speed has been reached, the resistance is interally short-circuited using a relay. In this way, it is possible to leave the softstarter permanently in the main circuit with no additional power loss.
The values for starting torque and time to reach nominal speed can be
set on the stepless 10-gang potentiometer.

Technical data
Input voltage: 3 x 400 VAC / 3 x 440 VAC (without N)
Output: 3 x 400 VAC
Output current: 8.5 Amp.
Power: max: 3.5 kW
Operating temperature range: -20°C / +70°C
Mounting: On rails acc. to DIN 46277 or wall mounting with screws