The Thunderstruck Motors GFM (Ground Fault Monitor) measures the isolation between an electrical system ground and a separate High Voltage (HV) isolated system. It is designed for use in a wide range of Electric Vehicle (EV) systems and is highly configurable.

The GFM measures isolation between the two systems by applying a known resistance between the low voltage ground and both HV buses (positive and negative) in an alternating sequence, then measuring the very small resulting current. The advanced measurement algorithm allows the GFM to make accurate measurements in rapidly changing and noisy systems. The isolation measurement is reported in several forms: fault resistance, ohms/volt, and average fault location. Symmetrical, asymmetrical, intermittent, and capacitive faults can all be measured by the system.

The GFM intelligently uses measured isolation metrics to evaluate two configurable fault thresholds (warning and fault). The GFM has two outputs that may be configured to represent these faults, allowing an operator to create warning lights and system interlocks. The present state of the fault, the number of occurrences, and the history of each fault is available to the user. These fault conditions, as well as all measurements, are available over CAN bus using sID (standard ID) and eID (extended ID) based protocols.

Feature List

•Rapid and accurate isolation measurement
• Highly configurable
• Wide voltage range (30-500V)
• Fault location detection
• 2x programmable outputs
• 1x CAN Bus
• All measurements and information available over CAN bus
• CAN control of isolation measurement
• Factory calibrated
• Built in compatibility with:
o TSM MCU
o TSM EV Display
o Fellten CCS controller



Warranty: 1 Year
Voltage: 48-408 DC Volts
Origin: Made in the USA


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