Semiconductor soft starter 3RW3 M Motor M M Start M Motor with SIRIUS 3R soft starter M Load M B M B = Acceleration torque of motor M Start SIRIUS 3R soft starter with n U U e U S t t R Fig. 8-10: Load and motor torque as well as motor terminal voltage when operating with soft starter Selection criteria Note: In the case of the SIRIUS soft starters 3RW30/31, the corresponding soft starter must be chosen in accordance with the motor's rated current (rated current of soft starter must be > motor's rated current). The starting voltage, the starting time and the coasting time can be set by means of the three setting parameters.
The soft starter is optimally set when the connected motor starts smoothly, but swiftly. Ramp times of up to 20 sec. can be set. 8-16 Stand 08/99