The HV battery pack powers the high-voltage
electrical system with DC electricity. Positive and
negative orange coloured high voltage power
cables are routed from the battery pack, under the
vehicle floor pan, routed along the passenger side
propeller shaft and transmission tunnel to the
inverter/converter. The inverter/converter contains a
circuit that boosts the HV battery voltage from 288
to 650-Volts DC. The inverter creates 3-phase AC to
power the motor and generator located in the
transmission. Power cables are routed from the
inverter to each high-voltage motor (electrical
motor, electric generator, and A/C compressor).
The following systems keep occupants in the
vehicle and emergency responders safe from high
voltage electricity:
High Voltage Safety System
•
A high voltage fuse
❶
provides short circuit
protection in the HV battery pack.
•
Positive and negative high voltage power cables
❷
connected to the HV battery pack are
controlled by 12-Volt normally open relays
❸
.
When the vehicle is shut off, the relays stop
electricity flow from leaving the HV battery pack.
•
Both positive and negative power cables
❷
are
insulated from the metal chassis, so there is no
possibility of electric shock when touching the
metal chassis.
•
A ground-fault monitor
❹
continuously
monitors for high voltage leakage to the metal
chassis while the vehicle is running. If a
malfunction is detected, the hybrid vehicle
computer
❹
will illuminate the master warning
light in the instrument cluster and indicate
"CHECK HYBRID SYSTEM" on the multi-
information display.
•
The HV battery pack relays will automatically
open to stop electricity flow in a collision
sufficient to activate the SRS.
HIGH VOLTAGE SAFETY
– 11 –
High Voltage Safety System – Vehicle Shut
Off (
READY
-OFF)
High Voltage Safety System – Vehicle On
and Operational (
READY
-ON)
WARNING:
The high voltage system may remain powered for
up to 10 minutes after the vehicle is shut off or
disabled. To prevent serious injury or death from
severe burns or electric shock, avoid touching,
cutting, or opening any orange high voltage power
cable or high voltage component.
❶
❷
❷
❷
❸
❸
❹
7940 - Lexus A4 ERG Book 3/5/06 3:23 PM Page 11
