Skyjack SJ12 E Service Manual page 126

Section 5 – Procedures
Code Description
28-M2_VLOW PUMP VMN LOW
28-M2_VHI PUMP VMN HIGH
28-DRV_VLOW VMN LOW
241914ACA
126
Cause
The pump motor output is lower than
expected, considering the applied PWM.
While the pump motor is driven, the
feedback of its voltage is higher than
expected, considering the applied PWM.
Cause 1
Start-up test. Before switching the LC on,
the software checks the power bridge:
it turns on alternatively the high-side
power MOSFETs and expects the phase
voltages increase toward the positive rail
value. If one phase voltage is lower than
a certain percentage of the rail voltage,
this alarm occurs.
Cause 2
Motor running test. When the motor is
running, the power bridge is on and
the motor voltage feedback tested; if it
is lower than expected value (a range
of values is considered), the controller
enters fault state.
Display Module
Troubleshooting
A) If the problem occurs at start up
(the LC does not close at all}, check
the motor internal connections and
the motor power cables. If the motor
connections are OK, the problem is
within the controller.
B) If the problem occurs after closing
the LC (the LC closes and then
opens back again}, check the motor
internal connections and the motor
leakage to the truck frame. If no
problem is found on the motor, the
problem is within the controller.
C) If the alarm occurs when the
motor is running, check:
the motor internal connections;
▪
whether the motor windings/
▪
cables exhibit leakage towards
truck frame;
that the LC power contact
▪
closes properly, with a good
contact; If no problem is found
on the motor, the problem
is within the controller, it is
necessary to replace it.
Check the motor internal connections
Check if motor windings/cables
exhibit leakage towards truck frame.
If no problem is found on the motor,
the problem is within the controller, it
is necessary to replace it.
If the problem occurs at start up (the
LC does not close at all), check:
motor internal connections
▪
(ohmic continuity);
motor power cables
▪
connections.
If the alarm occurs while the motor is
running, check:
motor connections;
▪
that the LC power contact
▪
closes properly, with a good
contact.
If the motor connections are OK, the
problem is within the controller, it is
necessary to replace it.
SJ12 E, SJ16 E, SJ20 E