Motor stator test system uses negative pressure to detect vulnerabilities
Foothill Ranch, CA. Chroma Systems Solutions Inc. has announced the release of its negative-pressure 1920 Motor Stator Test System. Specially designed for motor stator coil production and quality assurance testing, the 1920 performs up to 40 channels of testing required to detect vulnerabilities in quality and reliability in stator wire and windings.
Integrated into the system is Chroma’s 19036 Wound Component EST Analyzer, which performs AC and DC hi-pot testing, insulation resistance measurement, 4-terminal DC resistance measurement, and impulse winding testing with a built-in 10-port scanner; Chroma’s 3252 LCR Meter for Ls/Q and winding phase measurement; a vacuum system; and a custom test fixture. System software provides a user-friendly test control and program editing interface, a display of test results, data recording, and file management.
The negative pressure testing environment allows motor manufacturers to improve product quality with less risk of damage to the units under test. Per Paschen’s Law, gas CIV (corona inception voltage) is nearly proportional to the air pressure at a fixed gap distance. So when the air pressure drops to a near-vacuum state, the CIV is much lower. For example, when atmospheric pressure is at 760 mm/hg, it could need 30 kV to get to the breakdown voltage point between the insulation layer and core. However, Chroma’s 1920 system allows the atmospheric pressure to drop to 76 mm/hg, where only 2.4 kV is required to test the corona discharge. Therefore, it is possible to find winding defects at lower hi-pot and impulse winding test voltages, which enables users to not only test for failure but also repair the defect since there is less damage to UUT.
The Ls/Q (Quality factor) check enables users to find defects in the coil, which may look normal but may become hotter than typical after assembly as a completed motor. Rotation check is provided to verify if the winding connector assembly is correctly executed and can provide phase detection with its built-in LCR meter and a Hall sensor module or a real-rotation detection sub-system. The Chroma 1920 system is also equipped with a swappable fixture to increase test speed.
