Soft-starts cut starting currents by `30% more than others`
The Swedish motor control specialist Emotron has launched a range of soft-starts which, it claims, reduce starting currents by up to 30% more than conventional soft-starts. The MSF 2.0 starters use torque control to optimise start and stop sequences. This allows smaller fuses and cables to be used, cutting installation and energy costs.
The soft-starts (above) span power ratings from 7.5kW to 1.6MW, and current ratings from 17A to 1.65kA. They are claimed to have other attractions, including a shaft power monitor that detects conditions such as jammed crushers or dry-running pumps, allowing preventative actions to be taken before damage occurs.
When the soft-start is controlling a fan, programmable inputs can be used to control the direction of rotation without needing a PLC. An external alarm signal can stop the motor. Fans that are spinning the wrong way can be started safely using a spin-start function.
When controlling a pump, an analogue sensor input can be used to detect start and stop levels. Linear stops eliminate the risk of water hammer and other potentially damaging conditions without needing motor-controlled valves.
When starting heavily loaded crushers, a torque boost function can accommodate the large peak loads.
Option cards support communications via buses (Profibus, Devicenet and Ethernet) and serial links (RS-232, RS-485 or Modbus), as well as providing analogue and digital outputs. A built-in display can show current, voltages, shaft power, shaft torque, energy consumption operating hours, and motor thermal capacities.
