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The Carlo Gavazzi Group


Heat pumps

Single phase compressor soft starters

Soft starters are widely used in heat pumps because they can minimize light flickering and reduce audible noise during compressor starts. Our soft starters, RSBS and HDMS are both tailored for single phase scroll compressors. They can typically reduce compressor starting current by >50% compared to a direct on line start thereby eliminating electrical and mechanical stresses.
Both RSBS and HDMS require minimal configuration as they are practically plug'n'play soft starters.

Three phase compressor soft starters

Scroll compressors starting current can be as high as 8 times the nominal current of the compressor. Whereas in small, fractional kW/Hp compressors this might not pose any issues, such transient currents might affect the stability on the voltage grid as ell as disturbance to sensitive equipment.
RSBD and RSBT seriesg3QxkF1SirM of soft starters are specifically targeted to scroll compressors. Their patented self-learning algorithm automatically adjusts internal parameters to minimize compressor starting current whilst maintaining a start up time of around 600 ms. All this is achieved without a single adjustment from the user making them ideal for OEMs.

Variable frequency drives for compressors

Heat pumps are required to reach higher seasonal efficiencies to be placed on the market. The need to be highly efficient also in partial load operation requires a new technology of compressors that can work at low and high speeds. Both permanent magnet (PMAC) and brushless DC (BLDC) compressors are now commonly used in heat pumps.
RVPM is our variable frequency drive (VFD) that can work with 1-phase input and 3-phase input PM, BLDC as well as induction motor compressors.
RVBS is an open-board VFD designed for induction compressors up to 0.75kW (1Hp). Its compact design makes it ideal to fit in electrical enclosures with limited space.

Solid state contactors

Flammable refrigerants are also being deployed into heat pumps as part of the phase out of HFC refrigerants. One approach is to move to arc free switching components such as solid state contactors to switch fixed speed compressors on and off.
A solid state contactor comes with an integrated heatsink and is also DIN rail mount making it an easy fit in heat pump panels. In terms of footprint it is quite similar to an electromechanical contactor.
RGC series of solid state contactors is available in 1-phase and 3-phase (2-pole and 3-pole switching) versions and, with already UL approved motor ratings, it is also suited for switching of compressors.

DIN-rail mount energy meters

Real-time monitoring of heat pump electrical consumption is a good way to check for proper operation. By calculating the ratio of the electrical consumption to the thermal out put power an instantaneuous indication of the energy efficiency (COP) can be obtained.
Our wide range of compact, DIN-rail mount energy meters comes with direct connection and offers all the required features for such real-time measurements.

Three-phase voltage relays

Scroll compressors cannot operate in reverse as this will cause overheating and a shorter lifetime for the compressor. A good practice for detecting incorrect phase-sequence is to install a phase-sequence and phase-loss monitoring relay to stop the equipment in case of failure. Incorrect voltage also undermines the compressor service life so, when this is perceived as a risk, voltage monitoring is added.
Our DPA51 and DPB51 monitoring relay series are popular series of products with 3-phase heat pumps. Thanks to their compact size, self-powered design and wide operating voltage, they fit easily into any electrical panel.