FSG Rules:

EV 6.3 Insulation Monitoring Device

EV 6.3.1 Every vehicle must have an IMD installed in the TS system.

Requirements:

EV 6.3.2 The IMD must be a Bender A-ISOMETER® iso-F1 IR155-3203 or -3204 or equivalent IMD approved for automotive use. Equivalency may be approved by the officials based on the following criteria: robustness to vibration, operating temperature range, IP rating, availability of a direct output, a self-test facility, and must not be powered by the system which is monitored.

Electrical Demands:

EV 6.3.3 The response value of the IMD must be set to ≥500 Ω/V, related to the maximum TS voltage.

Positioning Requirements:

EV 6.3.4 The IMD must be connected on the vehicle side of the AIRs.

EV 6.3.5 One IMD chassis ground measurement line must be connected to the grounded TSAC or the respective grounded enclosure of the IMD. The other chassis ground measurement line must be connected to the main hoop. Each connection must use a separate conductor, rated for at least maximum TS voltage. An open circuit in any of these ground measurement connections must result in an opened shutdown circuit.

Shutdown Circuit Reference:

EV 6.3.6 In case of an insulation failure or an IMD failure, the IMD must open the shutdown circuit. This must be done without the influence of any programmable logic. See also EV6.1.6 regarding the re-activation of the TS after an insulation fault.

EV 6.3.7 A red indicator light in the cockpit that is easily visible from inside and outside the cockpit even in bright sunlight and clearly marked with the lettering “IMD” must light up if and only if the IMD opens the shutdown circuit. It must stay illuminated until the error state has been manually reset, see EV 6.1.6. Signals controlling this indicator are SCS, see T 11.9.

Last Year 22:

The one we usues: IMD Type Bender A-ISOMETER ® iso-F1 IR155-3203
Its Response Value: 176.4 kΩ