Heat-pump soft starter
Carlo Gavazzi offers a digital soft starter with all the features required for optimal control of single-phase compressors such as those used in geothermal and similar heat-pump installations.
The RBS Compact starter is rated up to 25 A continuous current for 230 V AC 50 Hz motors. It incorporates special control algorithms to limit starting current and on-board diagnostics to ensure reliability for this form of heating.
Starting current is measured by the integral current transformer and limited to 40 A RMS, thus ensuring that installations meet the limits established by energy companies. A matching on-board capacitor is available to boost starting torque. The RBS is capable of 12 starts an hour and continuously monitors line voltage, automatically disengaging if it drops more than 15%.
Ramp-up time is preset to 0.6 s, well within the limits prescribed for the scroll compressors used in typical residential heat-pump applications.
Locked-rotor protection during starting improves the lifetime of the compressor and soft starter. A second start will be attempted before the unit shuts down until the problem has been rectified.
