Posted to News on 1st Jul 2007, 12:43
Soft starters are capable of more starts per hour
Carlo Gavazzi is introducing a new family of soft starters that combines a built-in bypass contactor with an external heat sink for enhanced performance. Applications include fans, blowers, pumps, conveyors, granulators, mixers and shredding machinery, lathes, carousels, cranes, industrial dryers and washing machines as well as car washes.
Compared with existing devices on the market, the RSHR-MIDI starters are claimed to offer an increased number of starts per hour. Three-phase motors up to 400V/18A can make up to 50 starts per hour and 250 starts/h are possible on 2.2kW motors. The overall range spans 1.5-22kW, comprising 6, 12 and 18A versions with 220, 400, 480 and 600V AC voltage models. A 110-530V AC option provides global coverage for multiple voltages.
RSHR models control two phases only, with the third phase continuously connected to the load. Soft starting and stopping are achieved by controlling the motor voltage using semiconductor devices. During normal running these semiconductors are bypassed by internal electromechanical relays. Starting and stopping time as well as initial torque can be independently adjusted by built-in potentiometers with rotary controls. The result is vibration-free starting with a dramatic reduction in mains dips and lamp flicker.
High power density
Din rail-mounted and only 45mm wide, the soft starters can be installed in the same space as existing models to provide up to 36 per cent higher rated outputs. The units also have built-in heat sinks, enabling them to be mounted side by side.
Coloured lamps on the front panel alert the operator to power-on, ramping, bypass and overheat status. There are also optional over-temperature protection, and end-of-ramp alarm output relays provide further flexibility for closed-loop control systems.
Standards compliance is assured through conformity to IEN 60947-4-2 and EMC Directive 89/336/EEC. The new starters carry CE marking, UL and cUL approvals and can be CSA approved if required.
