Big Joe J1-192 Maintenance Repair Parts Manual page 23

Table 3-3 Troubleshooting Chart (Traction/Lift Controller) - Continued
ERROR ERROR TEXT
19 LOGIC FAILURE #1
30 VMN LOW
31 VMN HIGH
37 CONTACTOR CLOSED The controller check if the MV contact is
38 CINTACTOR OPEN
BL-J1-192-0315 - 11-19-2019
POSSIBLE CAUSE
This alarm signals that an overvoltage/
undervoltage protection operation has
occurred.
Before the main contactor is turned on,
the SW turns on the top side Power
Mosfets and expects the phase V volt-
age to increase toward the rail capaci-
tor value. If the phase V does not
increase, this alarm occurs.
The alarm may occur when the initial
diagnosis is overcome, and the main
contractor is expected to be closed.
Then when the operator tries to move
the vehicle, but the +Batt terminal of
the controller is lower voltage than the
Battery voltage, this alarm occurs
(Main Contractor has lost the contact
although it is closed).
Before the main contactor is turned on,
the SW turns on the bottom side Power
Mosfets and expects the phase V volt-
age to fall to GND value. If the phase V
remains high, this alarm occurs.
closed when the coil isn't driven, trying
to discharge the capacitor bank. If they
don't discharge, the fault condition is
entered.
The main contactor coil has been driven
by the logic board, but the contactor
does not close.
FAULT CLEARANCE
Normally the overvoltage occurs due to
the regenerative braking energy
increasing the battery voltage; the
under voltage of the logic supply, can
be due to a depletion in the key volt-
age. First, check for the failure mode.
Then contact the Big Lift LLC Service
Representative to look for a counter-
measure.
This alarm may occur for a HW failure.
Replace the Controller.
If the problem occurs before the Main
Contactor closes, a power failure
occurred (e.g. a bottom side Power
Mosfet short circuited or a top side
Power Mosfet is broken) or a Logic
Failure occurred in the controller.
If the problem occurs when the operator
turns a moving vehicle, the problem is
the Battery positive is not connected to
the +Batt terminal of the controller
(check the continuity of the main con-
tactor).
If the problem occurs permanently,
replace the controller.
There are two possibilities:
1. A motor phase is not connected to
the controller or broken.
2. A Power Failure (e.g. a Bottom side
Power Mosfet opened) or a Logic
Failure occurred in the controller. In
this case, replace the controller.
It is suggested to check the contactor, if
it is mechanically stuck or burnt closed.
There are two possibilities:
1. The wires to the coil are interrupted
or not well connected.
2. The contact of the contactor is
defective.
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