Contactor and BMU operation
According to the NTSB Airworthiness Report on page 37:
The contactor is identified as part number 104CZ02Y01 from the French company Zodiac Aerospace. It is a normally-closed solenoid with single-pole single-throw contacts and does not have a latching feature. On page 32 it states that
the contactor is normally closed and was designed to open in the event of an overcharge situation.
Also from the same report on page 32 is some description of the battery monitoring unit (BMU):
In the event that monitoring thresholds are exceeded BMU1 and 2 will send a signal to the battery charger unit to discontinue charging (overcharge and over-discharge monitor).
BMU3 contains controls for the contactor and provides further monitoring for battery and cell overcharge.
BMU4 monitors for cell over-discharge, high current charge, and contains inhibitions signals that will latch in the event of an over-discharge or a battery high current charge.
In the event that the monitoring thresholds are exceeded, BMU3 and 4 will send a signal to the battery charger unit to discontinue charging.
There was mention in the report that the contactor had dual coils, but i have not found a datasheet for the device to see the electrical schematic.
Last edited by kenneth house; 2nd Apr 2013 at 19:31.