Study of Energy and Demand Savings on a High Efficiency Hydraulic Pump System with Infinite Turn Down Technology (ITDT)

Abstract

Detailed field measurement and verification of electrical energy (kWh) and demand (kW) savings is conducted on an injection molding machine used in typical plastic manufacturing facility retrofitted with a high efficiency hydraulic pump system. Significant energy usage and demand savings are verified for the retrofitted injection molding machine. The savings are realized by electronically attenuating the torque of a positive displacement pump irrespective of the volumetric flow required by the cycle. With help of a power analyzer, power quality issues are addressed. Some voltage distortion was observed due to the harmonic currents introduced by the control algorithm of the high efficiency hydraulic system. A comparative study of electrical energy and demand savings between an injection molding machine retrofitted with the high efficiency hydraulic pump system or variable frequency drive will also be presented.