High Voltage Safety

High Voltage Safety
The HV battery pack powers the high voltage electrical system with DC electricity. Positive and negative orange colored 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 are intended to help keep occupants in the vehicle and emergency responders safe from high voltage electricity:







High Voltage Safety System
- A high voltage fuse "1" provides short circuit protection in the HV battery pack.
- Positive and negative high voltage power cables "2" connected to the HV battery pack are controlled by 12-Volt normally open relays "3." When the vehicle is shut off, the relays stop electrical flow from leaving the HV battery pack.

WARNING:
The high voltage system may remain powered for Up to 1O 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.

- Both positive and negative power cables "2" are insulated from the metal chassis, so there is no possibility of electric shock when touching the metal chassis.
- A ground fault monitor "4" continuously monitors for high voltage leakage to the metal chassis while the vehicle is running. If a malfunction is detected, the hybrid vehicle computer "4" 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.







Electronic Power Steering System
The GS450h is equipped with a 37-Volt AC assist motor for the Electric Power Steering (EPS) system. The EPS computer generates 37-Volts from the 12-Volt system. The 37-Volt wires are isolated from the metal chassis and are routed a short distance from the EPS computer to the EPS assist motor in the engine compartment.

NOTE:
37-Volt AC has a higher arc potential than the normal 12-Volt DC.

High Intensity Discharge Headlights
Similar to conventional, non-hybrid, Lexus vehicles, the GS450h is equipped with low beam projector type High Intensity Discharge (HID) headlights. The light control unit, located inside the headlight assembly, contains a high voltage generator circuit that momentarily boosts 12-Volts to 22-kV that is applied to the bulb when the headlights are turned on. Once illuminated, the voltage drops to approximately 45-Volts.

WARNING:
High voltage is applied to the HID bulb socket when the low beam headlights are turned on. To avoid serious injury or death by electric shock do not touch the bulb socket when the headlights are turned on.