Troubleshooting; Introduction - MarelliMotori D-Vo Light Manuel D'utilisation

8. TROUBLESHOOTING

8.1.

INTRODUCTION

The following chapter complements the Troubleshooting section of the User and Maintenance Manual of the Marelli
Motori generator, specifically dealing with the issues related to regulation: in particular, it covers the main problems
that may occur during the normal D-Vo operations and that are related to the regulator only.
Some of the malfunctions listed below may also be due to other components of the generator, and not just to the
regulator; some regulator failures, in addition, may be caused by issues of defects not related to the machine, and
be due for example to devices not manufactured by Marelli Motori connected to it, to improper use by the operator,
etc.
For this reason, we recommend that you always refer to all the available documents, and in particular to the D-Vo
User Manual, to the User and Maintenance Manual of the generator and to the connection diagrams supplied as
standard, as well as to the documentation of all the devices not manufactured by Marelli Motori connected to D-Vo
and to the generator excitation system.
The following section provides general information about the checks to be performed in case of malfunctions or
regulation problems. It complements but doesn't supersede in any way the other control, calibration and protection
procedures, which are specified in this manual and that must be carefully read.
When following the steps provided below, always take into account the Safety Precautions (Chapter 2) and the
detailed instructions for each individual operation provided by the documents accompanying the generator.
Any alteration and/or operation on the connections or other parts of D-Vo must comply with the Safety Precautions
(Chapter 2).
Should the information provided by the available documents not allow to resolve the issue, please contact Marelli
Motori Services for further instructions.
8.2. TROUBLESHOOTING
PRELIMINARY NOTES:
•
Should any of the malfunctions described below occur, it is assumed that before searching for the possible
failure/cause of the malfunction you disconnect from the regulator any connected devices (overexcitation
device, external remote controls, etc.).
Should the problem not reoccur while only the D-Vo unit is in operation, we recommend that you reconnect all
the accessory devices one at a time, in accordance with the supplied diagrams, until you identify the one that
causes the malfunction. Then refer to the User Manual of the thus identified device.
•
The instructions below assume that the D-Vo protections and limiters are activated.
Follow the procedures described below according to the malfunctions and/or symptoms you detected
With the generator running at the rated speed, no load, the voltage at the output terminals is equal to the residual
voltage of the machine.
Step 1 Check the connections.
In case of improper or missing connections, perform them again in accordance with the diagrams
supplied along with the generator.
Otherwise, move to Step 2
Step 2 Check the de-excitation contact (component not supplied by Marelli Motori).
Replace the contact if the latter is damaged/not working.
Otherwise, move to Step 3.
Step 3 Check whether the de-excitation contact has been opened by the relevant control system, particularly in
response to a D-Vo alarm. In the latter case, identify which alarm occurred (this can be verified by
performing a control system diagnosis or by referring to the alarm signalling systems of D-Vo,
Paragraphs 4.7 and 7.3.5)
If the de-excitation contact has been opened due to a D-Vo alarm, follow the user instructions for the
specific alarm contained in this manual.
Also carefully read Steps 10, 11 and 12, regarding the interventions for D-Vo alarms.
For information on de-excitation contact tripping causes not related to D-Vo, refer to the user manual of
the contact control system (components not supplied by Marelli).
Otherwise, move to Step 4.
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D-Vo Light – Marelli Motori
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