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Task 8.7 – Functional Test on thermostats / thermistors and temperature switch assemblies
OPERATING INSTRUCTION AND TECHNICAL REQUIREMENTS (TR) INSTRUCTIONS / EVIDENCE WHEN DEVIATIONS FROM TR
ATTENTION
Spare parts used for replacement have to comply with the IPL.
Before disassembly, discharge the battery with 0.2*I
1
to 0.5 V
per cell.
Do not overheat the device. Temperatures above 110°C can damage
the switch.
NOTE
Identify the thermostats that operate above room temperature
and proceed test 1, otherwise Test 2.
NOTE
Temperature switch assemblies shall be tested at the annual
maintenance. Alternatively, these may be replaced.
For function testing it is necessary to disassemble the temperature
sensing harness from the battery.
Test 1: Thermostats above ambient temperature
1.a Identify the thermostat type and its switching temperature
according to Appendix 4
1.b Disassemble the battery to the state necessary to remove
the switch assembly together with the corresponding connector
1.c Fix the link with the thermostat on the test fixture
1.d Connect the relevant pins in the interface connector of the
thermostat assembly to an ohmmeter
1.e If necessary, connect a thermocouple on the link as close as
possible to the switch
1.f Record the ambient temperature
1.g Record the measured thermal switch position at ambient
temperature (opened or closed)
1.h Heat the fixture to a temperature of 10°C above the
switching temperature and maintain it at this level until the
switch operates
1.i
Record the corresponding temperature when the switch operates
1.j Remove the heat source, allowing the link to cool whilst
monitoring the ohmmeter for the thermostat to switch to its
normal state
1.k Record the temperature at which the thermostat switches to its
normal state
1.l Identify faulty switches that do not switch or frequently switch
within the switching temperature range
1.m Refit the switch assembly on the battery.
Replace the thermostat / thermistor assembly in accordance
with Task 10.4.
The document reference is online, please check the correspondence between the online documentation and the printed version.
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