Section 8.Theory of Operation

System Architecture

This truck can be configured to accept either a 36V or 48V battery. The truck uses AC drive and lift technology. The standard truck uses conventional hydraulic controls via lever operated spool valves mounted on the right side console. An optional configuration uses fingertip controls mounted on an armrest to the right of the operators seat. A DC/DC converter provides 24V to the cooling fans, brake, tail, rotating, and work lights.

The electrical control system consists of the components listed in Table8-1.

Model 4700 Maintenance Manual

Component Function

*Vehicle ManagerServes as an interface for all control signals and performs analog/digital signal conversions. Manages tail and brake light operation based on traction motor encoder input. Shares primary memory with the Operator Display.

*Traction Power Amplifier (TPA)Powers the traction motors

*Pump Power Amplifier (PPA)Powers the pump motor

DC/DC ConverterConverts battery voltage to required DC voltage

*Operator Display (OD)Displays truck systems information. Shares primary memory with the VM.

*Armrest BoardOptional Fingertip Controls/VM interface

*Hydraulic Control BoardCoil driver board for hydraulic solenoids. Required for optional Fingertip Controls

Contactor 1 (CT1)Provides B+ to the DC/DC Converter and Hydraulic Control Board (for optional Fingertip Controls)

Contactor 2 (CT2)Provides B+ to the PPA

Contactor 3 (CT3)Provides B+ to the TPA

*Electrical control system components communicate via a Control Area Network (CAN-Bus).

Publication 1160093, Issued: 20 May 2013