New concept for power measurements and efficiency analysis of electric motors

The new eDrive package from HBM combines continuous, rapid measurement data acquisition with a power/efficiency analyzer and an oscilloscope. The GEN3i mobile data and transient recorder now offers the most accurate torque transducer in the world in its class, the T12, as well as distributed temperature measurements to form a powerful, integral measuring and analysis system. Users can continuously save measurement data from as many as 18 current and voltage channels for measurements of up to 1000 volts, temperature channels and torque and rotational signals at a sampling rate of up to 2 MS/s. The torque and rotational signals are available for measurements on the mechanical side with a differential or gear. Results of computations such as efficiency calculations can be represented graphically, which allows them to be verified quickly.

The system is based on a software program developed for electric motor and inverter measurements. For shorter cable lengths, the complete system is placed directly on the electric motor, which reduces interference. Complete operation is available from the PC via an optical Ethernet interface.

A power meter provide a complete characterization of the electrical drive train. The eDrive system from HBM shows all calculated results including effective, reactive and apparent power during the measurement. The system also allows for more extensive verification and analysis of the corresponding raw data. A freely programmable formula database is used to determine equivalent circuit diagrams, calculate air gap or cogging torques and to perform a dq0 transformation to analyze the inverter response.