EA Maintenance

Table of Contents

Engine Maintenance

Troubleshooting Chart: Injector Faulty
Troubleshooting Chart: Excessive Smoke
Troubleshooting Chart: Starting Problem
Troubleshooting Chart: No Power
Troubleshooting Chart: Start And Stop

Alternator Maintenance

Alternator Faults And Remedial Measures
Faults ObservedPossible Causes Verification and Remedy
I. Alternator does not excite itselfLink L1-L11 on internal strip L1 is missing or making bad contactSet Link L1-L11 properly.
Field suppression switch, if provided, did not closeCheck Field suppression switch
Pilot exciter circuit has an interruption Check the connection from pilot exciter to terminal strip L1, L2 and to the exciter panel
Residual magnetism is too lowApply separate excitation from a 4.5 V … 12 V battery until excitation is building up; + pole of battery to L1, - pole of battery to K1 both on the terminal strip L1. (Caution: If the starting battery is used for this purpose, it should not be grounded, as the excitation circuit is already grounded on one point.)
Speed of prime mover not correctMeasure speed and if not correct, adjust it
Main exciter circuit is interruptedCheck rotating rectifiers, replace faulty cells or the complete set
U-diode, if included, is faultyDisconnect U-diode, check it as any other diode in by-pass and blocking direction. If no spare diode is available, just remove diodes. (Caution: Without U-diode the rotating rectifier is not protected against over-voltages)
Varistor, if included, is faultyCheck visually and replace, if faulty. If no spare varistor is available, just remove it. (Caution: Without varistor there is no protection of rotating diodes against over-voltages)
Diodes n1 of regulators are faultyReplace regulator 
The relay d1 is faultyInitiate self-excitation by means of a battery. If the alternator voltage is getting too high, interrupt connection 16-17 on regulator circuit plate. If hereafter, nominal voltage is existent at the alternator terminals, relay d1 is faulty 
II. Alternator does not excite itself to nominal voltageRotating rectifiers are faulty Check the rectifier cells one after the other, replace faulty or complete set
Speed of prime mover not correctCheck Speed, if necessary, re-adjust
III. Alternator does not excite itself at no-load to nominal voltage to break down under loadRotating rectifiers are faulty Check the rectifier cells one after the other, replace faulty or complete set
Speed breaks downInspect governor of diesel engine
IV. Alternator does not excite itself to nominal voltage; voltage is hunting between 40% and 70% of nominal voltageThe voltage measuring circuit is interrupted somewhere, e.g. the link 6-8 on L1 of the voltage reference adjuster is missingCheck the setting of all the links of strip L1 at the inside of the terminal box (refer to the connection diagram supplied with the machine), if necessary re-arrange the links
V. Alternator excites to an excessive voltage; manipulation on the reference voltage adjustment are of no effectPower transistor p5 is faultyDisconnect the lead to its base (B), if the alternator continues to excite itself too high, the transistor is faulty
Relay d1 does not pull upInterrupt connection 16-17 on the regulator plate, if now nominal voltage is existent, relay d1 is faulty or the supply voltage to the relay is missing
Transformer m1 is faultyCheck the transformation ratio. When supplying to the transformers primaries with 110 V at terminal 1-2 of L3, 230 V at terminal 1-3 of L3, 425 V at terminal 1-4 of L3, 525 V at terminal 1-5 of L3, the secondaries should show at the conductors red/yellow 48 V, green/blue 48 V, black/grey 6 V
Fault in the regulator circuit plateReplace the regulator
VI. Alternator voltage is huntingSpeed variation of the prime moverThe frequency variations are caused by the prime mover; check the governor of the prime mover
Oscillation of the regulator circuitOscillations in the regulator circuit may arise, if incited by the prime mover. To correct this, it is generally sufficient to reduce the capacity of condenser ky on the regulator plate, in rare and more complicated cases it might becomes necessary to alter also condenser kx and the resistor rx


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