Milliohm Meters: Essential Testing for Hybrid and EV Diagnosis
Accurate low-resistance testing is an essential part of hybrid and EV diagnosis and repair. Learn how milliohm meters help technicians evaluate motor windings, verify bonding connections, and make informed repair decisions.
Description
Course Description
Hybrid and electric vehicle diagnosis requires precise electrical measurements, including resistance values that conventional multimeters may not reliably distinguish. This course focuses on the milliohm meter as an essential tool for evaluating electric motor windings, high-current connections, and equipotential bonding paths. Participants will explore equipment selection, four-wire Kelvin measurement, proper test setup, and interpretation of results using manufacturer procedures and specifications. Practical examples will connect low-resistance testing to fault diagnosis and post-repair verification, while addressing safe component isolation and the differences between winding resistance and insulation resistance testing.
Topics Include
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Why milliohm testing matters in hybrid and EV service
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Recognizing the limitations of conventional multimeters
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Selecting meters and accessories for hybrid and EV applications
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Using four-wire Kelvin measurement techniques
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Safely preparing and isolating components for testing
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Evaluating motor-generator winding resistance and phase balance
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Assessing high-current connections and equipotential bonding paths
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Identifying measurement errors caused by temperature and poor contact
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Applying OEM specifications to diagnosis and post-repair verification
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Understanding when to use milliohm testing versus insulation resistance testing