FAQ #387
Insulation Monitoring Device Startup

Last Updated On 10/24/2025 05:59:22 PM by

sayovitz

Question
When the Insulation Monitoring Device is first started, it shows a fault for several seconds.
How does this affect the IMD Indicator Light and the Tractive System Status Indicator?
Answer
Formula SAE Rules EV.7.6 does not include the Insulation Monitoring Device startup process.
The IMDs usually used for Formula SAE Electric may give a fault during the startup process. This is the design of the IMD and cannot be changed.

For teams to design their monitoring circuit, more guidance is provided below. Per Formula SAE Rules GR.4.2.3, this guidance is Incorporated by Reference and supplements the Formula SAE Rules

During the IMD startup period:
1. EV.7.6.4 and EV.7.6.5 do not apply since the IMD is not able to monitor the Tractive System until the startup is complete
2. The IMD Indicator Light EV.7.6.6 may be ON
3. The Tractive System Status Indicator must meet EV.5.11.5 at all times. Indication of a fault (EV.5.11.5.b) will be a Red Car Condition EV.12
4. A hardware or software method may be included to prevent the false positive Tractive System Status Indicator indication

When the IMD startup is completed:
EV.7.6.4 and EV.7.6.5 must be met when the Low Voltage (GLV) system is ON
No Attachments
Rule Numbers
2025:EV.7.6.4 
2025:EV.7.6.5