Panpu SRM Switched Reluctance Drive System Case Study | Rubber & Plastic Products Factory | Energy-saving Retrofit of Injection Molding Workshop Oil Pumps with Process-Stage Speed Control

Load fluctuations during the injection molding cycle are significant: high torque and fast response are required for mold clamping and injection, while low flow is sufficient to maintain pressure during holding and cooling. The original system used a relief valve to unload during low-pressure phases, converting electrical energy into hydraulic heat. This wastes energy and accelerates oil degradation. The retrofit uses an SRM225S-15 switch reluctance motor paired with an SRD controller. Leveraging its constant torque below rated speed and a speed range of 50~2000 r/min, the pump speed is adjusted in stages according to the process curve, matching oil supply to actuator demand. With an SRD response time of 0.2 seconds and speed accuracy of ±1.5r/min, it meets the rapid speed switching requirements of the injection phase. Its ability to handle frequent forward/reverse rotation and start/stop cycles aligns perfectly with the periodic actions of injection molding machines. The controller includes protection features such as motor overload delay (15 seconds), stall delay (1 seconds), and overcurrent threshold at 160% of rated current. It also supports multi-parameter data acquisition, allowing all machine running data to be integrated into an IoT platform for centralized monitoring. After the retrofit, single-machine energy savings reached 28%. Hydraulic oil temperature decreased on average, reducing cooling water load and noise levels, while extending the replacement intervals for seals and oil.