Section 3 - Component Checks; Dc Powered Machine - Hydraulic Pump; Dc Powered Machine - Power; Dc Powered Machine - Power Module - JLG T350 Troubleshooting Manual

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Table of Contents

3.1 DC POWERED MACHINE - HYDRAULIC PUMP

Step Pretest Instructions

3.1.1

3.1.2 Engage enable and lift up

switch

3.1.3 Engage enable and lift up

switch

3.1.4 Engage enable and lift up

switch

3.1.5 Engage enable and lift up

switch

3.2 DC POWERED MACHINE - POWER

Step Pretest Instructions

3.2.1

3.2.2 Disconnect X105

3.2.3

3.2.4 Pull the ground emergency

stop switch and place key

switch in ground position

3.2.5 Pull the ground emergency

stop switch and place key

switch in ground position

3.3 DC POWERED MACHINE - POWER MODULE

Theory of Operation

The Power Module is essentially a "low-side" switch for the pump motor. The positive terminal of the pump is tied to Battery

Positive after the Line Contactor. The negative terminal of the pump connects to the P Terminal of the Power Module, which

switches current through MOSFET transistors to the Battery Negative.

For variable speed pump operation, the MOSFET transistors switch On and Off at high frequencies (16kHz). The Duty Cycle

is varied to control the voltage applied to the pump motor. When the MOSFET's spend 50% of the period On and 50% Off,

3121203

COMPONENT CHECKS

SECTION 3.

Test

Voltage between B+ and B-

(X102 and X101) =Vbatt?

Voltage between M1 and M2

(X103 and X104) =Vbatt?

Voltage between X115 and

X114=Vbatt?

Voltage between X115 and

X101 =Vbatt?

Voltage between X114 and

X102 =Vbatt?

Test

Disconnect batteries and

check for 6V across each bat-

tery

Check for 24V across X105

Measure Voltage across Power

Module X102 (B+) and X101

(B-)

Check Voltage on X008.2

Check Voltage on X009.87

T350 T500J