Slip Ring Motor Liquid Resistor Soft Starting System(HV-LRS)


Application scope
      It is used for the smooth soft start of slip ring motor, rated voltage of 380V ~ 15KV
Widely used in cement, steel, mining, paper industry, oil industry etc.
Working principles
     A special liquid resistor is connected in series to the rotor circuit of slip ring motor; the liquid resistor get to work when the motor starts and its resistance gradually decrease during the preset time, so as the motor can start smoothly and accelerate eventually at minimal rated current and maximum torque. After start process is completed, the rotor circuit is shorted by the contactor. Its low starting current results in no impact on motors, load and power system as well as in no harmonic to affect the power system.      
       No maintenance is needed for the starters as automatic water filling system controlled by electrolyte level sensor and PLC can automatically fill the electrolyte tank with required amount of water when necessary.(optional)

Main technical parameters
       Initial start current Iq≤1.3In      
       Start time(s) 10~60, preset, adjustable on site
       Start attempts(times): continually (ambient  temperature 25℃)      
       Normal working temperature of liquid resistor:0-70℃
       Protection level IP20,IP30

Standards adopted
        Low voltage whole set switches and Controllers
        GB/T14048.1-2000          IEC60947-1:1999 
        GB7251.1-1997               IEC439-1:1992 
        Automatic liquid resistor starting, speed
        regulation and compensating controller Q/FZR1-2003

System Diagram 


II．Inner contructure