CLARK FORKLIFT ET204 Troubleshooting the EV T5 Control TECHNICAL TRAINING MANUAL

ET204

Troubleshooting the EV T5 Control

TECHNICAL TRAINING Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Contents About this Class...........................................................................................................

Class Objectives.................................................................................................

Class Content....................................................................................................

Sequence of Operations....................................................................................

Troubleshooting...................................................................................................

Quiz...................................................................................................................

About Safety......................................................................................................

Section 1. EV-T5 Control Sequence of Operations.....................................................

Identification of Abbreviations.........................................................................

Identification of Symbols...................................................................................

Sequence 1. Drive Control................................................................................

Sequence 2. Connect the Battery.....................................................................

Sequence 3.Close the KeySwitch.....................................................................

Sequence 4. Energizing the Line Contactor....................................................

Sequence 5. Energizing the Directional Contactors........................................

Sequence 6. Turning 'ON' the MOSFETs.................................. .......................

Sequence 7. Turning 'OFF' the MOSFETs,Capacitor Charging and Flyback Sequence 8. Accelerator, Thermal Protectors, and PMT..............................

Sequence 9. 1A Contactor Operation...............................................................

Sequence10. Plugging.......................................................................................

Sequence 11.Emergency Reverse.....................................................................

Section 2. EV-T5 Control Troubleshooting.................................................................

Symptom 1. Line contactors will not close.......................................................

Symptom 2. Line contactor closes, Directional Contactors Will Not Close...

Symptom 3. Directional contactors close, no power, and No audible Sound, truck inoperable with accelerator in FET range........................

Symptom 4.One Directional contactors closes With Normal Operation But Other Directional Contactor Will Not Close...............................

Symptom 5. PMT Trips After Operating In lA Mode and Returning to FET Mode.............................................................................................

Symptom 6. Contactor Closes, Higher Than Normal Stall Currents in FET Mode. C/L Pot Will Not Adjust. Contactors May Open Once and Then Remain Open...............................................................

Symptom 7. 1A contactor will not close on Rider............................................

Symptom 8. 1A Contactor Will Not Close on Walkie......................................

Symptom 9. Stiff Plug and Distance Will Not Adust......................................

Section 3. Component and Card Adjustment..............................................................

Card Adjustments .............................................................................................

Component Identification..................................................................................

Internal Wiring.................................................................................................

Checking Components (Battery).......................................................................

Checking Components (MOSFETs)..................................................................

Checking Components (#3&4 REC)...................................................................

Checking Components (Capacitor)....................................................................

Checking Components (TP, Shunt & Snubber)................................................

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3 3 3 3 4 4 5 6 6 7 8 10 12 14 16 18 20 22 24 26 32 34 36 37 38 39 40 40 41 42 43 44 45 46 47 48 49 50 51 52

EV T-5 Control page l

© Copyright Clark Equipment Company 1991 Revised 1998.

EV T-5 Control page 2

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About this Class The most important part of an electric truck is the control that operates the electrical components. Knowledge of this control - how it works, and how it operates the other components - is vital to maintenance and service. This class is designed to teach you how the EV-T5 MOSFETs Control operates and how you can diagnose and troubleshoot problems with the control.

The EV-T5 CONTROL is an electronic device that controls electrical power supplied to the vehicle drive motor to provide smooth power to move the truck and to minimize power drain from battery.

The control consists of a Transistor unit and a contactor assembly unit. The Transistor unit monitors power demand of the truck and then responds by controlling the power applied to drive components. The contactor panel contains switching devices to direct heavy power loads to the drive motor and its components.

Class Objectives There are two primary objectives for this class. Upon completion of the manual and the class you will be able to: 1. Trace each sequence of operations on a basic wiring diagram as a way to demonstrate your understanding of the control and its operation 2. Make preliminary diagnosis of and troubleshoot problems related to the control and its components.

These objectives are intended to give you a sound understanding of how the Control works and lay a groundwork for problem diagnosis and troubleshooting.

Class Content There are two major sections in this book that will be covered in the class; the Sequence of Operations and Troubleshooting.

Sequence of Operations This section includes: • a list of abbreviations used in the text and on the wiring diagram • a legend defining the symbols used on the diagrams • a list of the control sequence of operations • a wiring diagram for each sequence.

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EV T-5 Control page 3

To meet one of the objectives of the course, you will be required to trace the operation sequence on the diagram as a way to completely understand how the control works.

Troubleshooting This sections includes: • a list of basic, required steps necessary to initiate troubleshooting • troubleshooting diagrams listed according to preliminary symptoms of the problem • where necessary, explanations, illustrations, and testing procedures related to troubleshooting a particular component.

Quiz At the completion of this program, you will be required to take a quiz. This is a way to help determine if you are meeting the objectives of the cow·se.

If you follow both the Sequence of Operations and the Troubleshooting materials closely, system operation will be clearer. This will help you to understand the electrical system more completely and diagnose and troubleshoot Control problems more effectively.

For additional information refer to SM 568.

EV T-5 Control page 4

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About Safety The following messages may be used to emphasize important information: Note: This message is used when special information, instructions or identification is

required relating to procedures, equipment, tools, pressures, capacities and other special data.

Important: This message is used when special precautions should be taken to ensure

a correct action or to avoid damage to or malfunction of the truck or a component.

CAUTION: This message is used as a reminder of safety practices which can result in personal injury if proper precautions are not taken.

WARNING: This message is used when a hazard exists which can result in injury or death if proper precautions are not taken.

DANGER: This message is used when an extreme hazard exists which will result in death or serious injury if proper precautions are not taken.

When checking electrical components on an electric truck, always raise the drive wheels off the floor and put blocks under the truck, disconnect the battery, and discharge the capacitor. These actions prevent injury to yourself and damage to the truck. Always familiarize yourself with the safety information in the Operator's Manual before you operate the truck.

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EV T-5 Control page 5

Section 1. EV-T5 Control Sequence of Operations This sequence of operation is designed to provide a complete step-by-step description of the operation of Clark lift trucks equipped with GE model EV-T5 MOSFET control.

Please read each operation sequence and then trace the sequence onto the diagram as described.

If you will follow the steps carefully, and not skip around you should be familiar with the entire operation of the lift truck electrical system. Then, if you wish to review any particular part or sequence, consult the Table of Contents and refer to the particular sequences involved.

Identification of Abbreviations The following abbreviations are used in the text and in the wiring schematics: A B.D.I. 1A IC F FWD FU HM p L FET R REV FIL SW CTP FTP

EV T-5 Control page 6

Armature Battery Discharge Indicator Bypass Contactor Assembly Capacitor Forward Contactor Assembly Forward Directional Switch Fuse Hour Meter Main Pump Contactor Assembly Line Contactor Assembly Field Effect Transistor Reverse Contactor Assembly Reverse Directional Switch Filter Switch Thermal Protector [ Capacitor ] Thermal Protector [ Fets ]

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Identification of Schematic Symbols The following symbols are used on the wiring schematic:

..L.

--- �

MOMENTARY SW1TCH

�

NORMALLY OPEN SWITCH

a ,.

___..d'"'�

NORMALLY CLOSED SWITCH NORMALLY CLOSED SWITCH HELO OPEN NORMALLY OPEN SWITCH HELD CLOSED

..,a ---..,.-H

---1:J-c::J---"r-�•@A•;

NORMALLY CLOSED POWER POINTS NORMALLY OPEN POWER POINTS PLUG-IN CONNECTION FUSE

RESISTOR COIL (CONTACTOR COIL OR RELAY COIL) PERNINENT MAGNET MOTOR MOTOR ARMATURE INDUCTOR (MOTOR FIELD, REACTOR, CHOKE, ETC.)

�

,

Lr'

-w

THERMAL PROTECTOR MOSFET or FET

(Metal Oxcld• Semiconductor Fleld Effect Transletor) DIODE

--;E--

CAPACITOR CURRENT MONITORING SHUNT

�

VARRIABLE RESISTOR {ACCELERATOR)

-- - --J

HORN TW1STEO PAIR WIRES

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EV T-5 Control page 7

Sequence 1. Drive Control Standard schematic is shown with all switches and contacts in normal off position. No circuits are operating. Please identify the four basic areas of circuitry.

1. Power 2. Speed 3. Directional 4. Accessory

EV T-5 Control page 8

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