Electric Motor Test Stand for Small Electric Motor Dynamometer

The Challenge

The manufacturer, gearing up to enter a new market, needed a new test stand for evaluating small motors and inverters without divulging specific Unit Under Test (UUT) details due to proprietary concerns. ACS was tasked with creating a semi-mobile test stand with a small footprint and engineering customized data acquisition systems.

The client needed to analyze the power and durability of their motor system development. Essential objectives encompassed assessing power efficiency, electrical noise levels, and overall functionality at various torque operating points.

Key concerns involved collecting power metrics like apparent and reactive power, mechanical power, utilization, and efficiency for both motor and inverter while meeting a minimum 1kHz sampling rate for highly precise data collection.

This combination of stringent data acquisition demands, undisclosed proprietary specifics, and spatial constraints formed the crux of ACS' challenge in engineering a tailored small electric motor dynamometer test stand for the client's unique testing needs.

The Solution

The ACS team delivered a compact test stand that houses the motor testing dynamometer, power analysis data acquisition system, and battery simulator. The small footprint dictated careful component selection and off-the-shelf parts integration design.

Because the manufacturer wanted the flexibility to use the mobile test stand in different areas, they couldn’t assume the test area would have enough clearance for the workspace. Thus, the engineers designed a unique drawer system that allows testers to change UUTs and connectors within a narrow vertical plane.

The integrated electric motor test stand facilitates simultaneous measurements across various systems, enabling synchronized data capture, including from the motor testing dynamometer, battery simulator, HBM power analyzer, and cooling system.

ACS software engineers integrated specialized DAQ systems that collected high and low speed data across multiple sources, both digital and analog data. They used ACS framework as the platform to build synchronized data collection across all the different data sources.

To ensure safety within the confined space, the ACS team opted to use a back EMF monitor to provide zero-speed monitoring of the dyno. The entire test stand is fully enclosed. The guard system uses safety locks intended to keep all enclosures closed until the dyno is at zero speed and the battery simulator is disconnected. As a backup safety precaution, the designers selected finger-safe connectors to protect the testers as they swapped out test units.

The Outcome

ACS delivered a seamlessly integrated, mobile test stand tailored for testing various electric motor and inverter models in active development. Its compact, vertically stacked design has a single power source distribution system, giving the client maximum flexibility to use the electric motor test stand throughout its lab facilities.

The customized DAQ system provides the manufacturer with a coherent and time-synchronized view of all the data for comprehensive analysis. The systems’ interface mirrored those ACS built for this client’s larger dynamometer test cell, so their test personnel could easily transition between both test cells.

Key Features

• Dynamometer performance: Engineered for 4kW (7kW peak) power output, precise torque control at 12Nm, and reliable operation at 11,000RPM with ±1RPM accuracy.
• Battery simulator versatility: 15kW capacity, adjustable to 48V, offering adaptable power supply for diverse testing needs.
• Test stand automation integration: Utilizing CAN/CAN-FD and EtherCAT communications, along with an Allen Bradley safety PLC for comprehensive control and safety in operations.
• Dual-speed data acquisition and electric motor software integration solutions: Integration of NI™ low-speed and HBM high-speed DAQ systems for comprehensive data collection and analysis.

ACS Services

• Designed and constructed customized test stand fitting within confined spaces, facilitating mobility and adaptability for electric motor testing.
• Software engineering on ACS framework for test stand operations, and data acquisition, including synchronized data collection.