The SRf-type rheostatic and contactor starters are devices which ensure regular starting of motors which are a part of conveyor belt systems or mining machines.

The SRf starter is a unit of connected resistive blocks with separate tappings. The blocks are connected with high-current terminals of contactors closing the circuit with  copper flats ensuring proper electric and mechanical strength. The entire unit is placed on a steel carriage protected against corrosion by hot-dip galvanization.

The resistive blocks are comprised of highly resistive steel and nickel alloy strips, which are coiled on steel rods. A system of micanite disks forms the electric and thermal insulation.
The control of contactors of subsequent starting stages is performed by means of a PLC controller at the dispatcher’s disposal or traditionally – using time-relays.

The number of starting stages, the resistance values of individual tappings, the start-up time and the profile of the resistive strips is individually determined in designs, giving consideration to the drive operation type and conditions.

The units allow for operation with 160 kW to 1000 kW drives.