Portescap Enhanced 42M048D Can Stack Stepper Motor for Three Way Valves
Valves are used in numerous applications to control the flow of heating or cooling fluids in an HVAC system. A new trend in the HVAC industry is the increased use of CO2 as a refrigerant, given that it has a higher heat carrying capacity and higher overall system efficiency as compared to conventional refrigerants. Since these characteristics are compliant with the new efficiency regulations, they led to the development of CO2 -based high temperature “three-way” valves. In a three-way valve, the refrigerant flow is confined within a closed loop, heat circulation circuit (two ways) and then diverted to the main distribution circuit on demand (third way). Since valve actuators can be placed closer to heating systems, valves using CO2 refrigerant need to function at a higher ambient temperature of 125°C.
A global HVAC manufacturing company needed to find a motorized solution that would tolerate the high ambient temperatures of their new three-way valves and they reached out to Portescap to provide a solution. The 42M048 can stack stepper motor was selected and modified to tolerate the high ambient conditions and exceeded the customer requirements. The R&D team performed a complete analysis of all components to determine the requirements that would allow the motor to operate at 125°C. A special coil was selected with a maximum winding temperature of 200°C with a modification of bearings, lubricants and glue type. Magnet strength typically reduces at higher temperature, but Portescap used a high-energy ferrite magnet to achieve the desired performance. Portescap’s experience with high temperature applications was key to developing a robust solution for the three-way valve application.