Soft starter

To date, the majority of scroll compressors in the market are designed for fixed speed. Driving such compressors at low speed might result in lack of lubrication of the scroll set which will increase the wear and tear of the scrolls resulting in loss of compression (in time), overheating of the compressor and hence shortening of the compressor lifetime.

Having said this, the softstarter's main function with scroll compressors is the reduction of the inrush current during startup. Via a Direct on line start, currents may reach 6 to 7 times (pr more) the nominal compressor current which is undesirable (voltage dips, light flickering, higher energy contracts etc)and sometimes utility regulations do not permit to go above a certain level of current during start.

Soft starters can also have integrated bypass relays which are activated as soon as soon as the compressor reaches its running speed. In this way, there are minimal heat losses on the softstarter and the compressor runs freely at its rated speed. Once at rated speed, the compressor noise is minimal. In fact, such compressors are used in domestic heat pumps all over Europe.