JLG X20JP - X600AJ Service Manual - Manual (Page 143)

SECTION 3 - CHASSIS & TURNTABLE
3121623 – JLG Lift – 3-119
INVERTER AND MAIN RELAY
Figure 3-47. 48 Volt Battery Pack - Inverter
Inverter has the following functions:
1. Transform the Direct Current coming from the Bat-
tery pack into Alternating current 3 phases for the
electric motor
2. Feed and manage the electric motor
3. Feed the external main contactor
Figure 3-48. 72 Volt Battery Pack - Inverter
1. Transform the Direct Current coming from the Battery
pack into Alternating current 3 phases for the electric
motor.
The choice of a three-phase alternating current electric
motor has been made to have the possibility to control the
rpm (and the current absorption) operating on the fre-
quency without limiting the torque (and machine’s perfor-
mances).
2. Feed and manage the electric motor
The inverter monitors the electric motor functions using a
rpm sensor and a temperature sensor located in the
motor. It manages the rpm reduction in case the power
required is high: in fact when the motor torque required is
too high, the inverter automatically reduces the rpms in
order to avoid an excessive power absorption dangerous
for battery performances.
JLG ECM1-2 controls the inverter to manage the rpm
according with the movement operated by the operator, in
order to optimize the performances and to keep the move-
ments smooth; this communications is performed by a
series of switches inside ECM1-2.
More details are showed in the wiring diagram.
Inverter manages the condition of low level battery pack.
When the charge level reaches 10% of the total capacity
(this information is provided by the BMS via CAN-BUS),
the inverter sets the rpm of the motor to half of the mini-
mum (tortoise) slowing down considerably the speed of
the movements. In this way the operator will be informed
about the necessity to charge the batteries even if it’s still
possible to move the machine for a few minutes.
3. Feed the external main contactor
Under the right conditions (no errors) the inverter feeds
the external main contactor (relay) in order to close the 48
or 72 Volts line.
This contactor is connected in series with the internal con-
tactor managed by the BMS, located inside the battery
pack.
The contactor are closed using the machine, otherwise
movements are not possible because the electric motor
cannot get any feed.
More details about the contactor connexions are showed
in the wiring diagrams.
In case of failures or problems, inverter interrupts the feed
to the external contactor.
Figure 3-49. Inverter’s contactor