CLARK FORKLIFT ET201 Troubleshooting the EV 1 Control TECHNICAL TRAINING MANUAL

ET201

Troubleshooting the EV 1 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 ........................................................................................ 1 Class Objectives .................................................................................. 1 Class Content ....................................................................................... 1 Sequence of Operations.............................................................. 1 Troubleshooting ........................................................................... 2 Quiz ............................................................................................. 2 About Safety ............................................................................................. 3 Section 1. EV-1 Control Sequence of Operations .................................... 4 Identification of Abbreviations .......................................................... 4 Identification of Symbols .................................................................. 5 Sequence 1. Drive Control ................................................................... 6 Sequence 2. Connect the Battery ........................................................ 8 Sequence 3. Battery Indicator and Pump Motor ................................ 10 Sequence 4. Hour Meter, Power Steering Operation, and S.R.O. .... 12 Sequence 5. Energizing the Directional Contactors .......................... 14 Sequence 6. Contactor Closing and Capacitor Precharge ................ 16 Sequence 7. #1 REC and #5 REC Turn On ...................................... 18 Sequence 8. 1C Capacitor Charging and Reactor Operation ........... 20 Sequence 9. #2 Rectifier Turn On and #1 Rectifier Turn Off .............22 Sequence 10. Flyback........................................................................ 24 Sequence 11. Accelerator Pot, Thermal Protector, and P.M.T.......... 26 Sequence 12. 1A Contactor Operation .............................................. 28 Sequence 13. Field Weakening Operation ........................................ 30 Sequence 14. Plugging ......................................................................32 Sequence 15. Plugging (continued) ................................................... 34 Sequence 16. Ramp Start .................................................................. 36 Section 2. EV-1 Control Troubleshooting ............................................... 38 Symptom 1. Forward and reverse contacts will not close ................. 39 Symptom 2. Reverse contacts will not close .....................................40 Symptom 3. Forward contacts will not close ...................................... 41 Symptom 4. Contacts close, then drop out - drive motor will not operate ............................................................................................... 42

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Symptom 4A. Contacts close, then drop out - drive motor will not operate (TW models only) .................................................................. 43 Symptom 5. Contacts close, truck does not run in SCR range ......... 44 Symptom 5A. Contacts close, truck does not run in SCR range (NS & NP 300, 500 only) .............................................................................. 45 Symptom 6. Contacts close, very low power in SCR range, control will hum .................................................................................................... 46 Symptom 6A. "B" contactor operation ................................................47 Symptom 7. Full SCR hum and power with accelerator in creep position ............................................................................................... 48 Symptom 8. Full power immediately, no SCA hum, accelerator is in creep position ..................................................................................... 49 Symptom 9. Improper closing of 1A contacts .................................... 50 Symptom 10. 1A contacts will not close ............................................. 51 Symptom 11. Plugging will not adjust ................................................52 Symptom 12. Truck wiring is grounded .............................................. 53 Symptom 13. Truck wiring is shorted ................................................. 54 Symptom 14. Miscellaneous problems .............................................. 55 Symptom 15. Dual motor card troubleshooting (rW models only) .... 56 Symptom 15. (continued) ................................................................... 57 Symptom 15. (continued) ...................................................................58

©Copyright Clark Equipment Company 1990.

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EV-1 SCA Control

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About this Class 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-1 SCA Control operates and how you can diagnose and troubleshoot problems with the control.

The EV-1 SCA Control consists of a control card and the electrical components it operates. The card monitors power demands and responds by controlling the power applied to system components.

The control operates a series of switching devices that enable it to direct the power load across different electrical circuits. These circuits control everything on the truck from the traction motors to forward and reverse drives and accessory devices. So your knowledge of the control system, the components it operates, and how to diagnose and troubleshoot control problems helps you to keep a truck in top shape and avoid down time.

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 class; the Sequence of Operations and Troubleshooting.

Sequence of Operations a list of abbreviations used in the text and on the wiring diagrams • 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-1 SCA Control 1

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

Quiz

About Safety Note

Important

CAUTION

WARNING

DANGER

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Section 1. EV-1 Control Sequence of Operations

Identification of Abbreviations

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P.S.T.D.

Steering Pump Contactor Coil Time Delay

SW

Switch

T.P.

Thermal Protector

Identification of Symbols

Sequence 1. Drive Control

Sequence 2. Connect the Battery

Voltages Present:

Note

Sequence 3. Battery Indicator and Pump Motor

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8. Battery voltage is applied to Card #1 at L3 through wire #10.

C. Battery indicator will now operate. Wire #10 connects it to positive, and #13 to negative.

D. Wire #10 also supplies voltage to PSD #3 and PSTD #4.

E. Operating the lift lever closes the lift switch.

F. The pump contact coil now gets voltage from wire #28.

G. The pump coil closes the contacts.

H. The pump motor operates.

Battery positive at all points, A through H.

Sequence 4. Hour Meter, Power Steering Operation, and S.R.O.

Sequence 5. Energizing the Directional Contactors

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The directional control switch has been moved to a forward position in a previous sequence.

A. The brake pedal must be released to close the brake switch points.

The brake switch is provided to prevent operating the motor with the brakes applied, since this wastes energy and may overheat components.

B. Depressing the accelerator pedal slightly will close the 1MS switch points.

C. With all switches in the forward directional control circuits closed, battery positive will be applied to terminals LS and L9 of the #1 card. This voltage, coupled with the voltage from the key switch on terminals L3, L4, L7 causes the card to complete the circuit from terminal R3 to terminal 1 on the P.M.T.D. D. The PMTD completes the circuit to negative, the forward contactor coil is energized.

E. If #1 REC is shorted, or the 1A tips are stuck closed, the black wire to #1 card plug pin #5 will be battery positive and the card will hold the contacts open (see Note).

Voltages present: A., B.

Not Applicable.

C. Battery volts on terminals LS and L9, 6 to 8 volts on R3.

D. Battery volts across F coil.

Wires are twisted in pairs to aid in suppressing voltage spikes generated by all coil type components in the control system.

Sequence 6. Contactor Closing and Capacitor Precharge

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

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