Variable lenguaje oral

It is not necessary to take any special precautions when merely inspecting the commutator, but on making adjustments to the wiring circuit, it is essential to take steps to prevent accidental "shorting." Disconnect the lead from the lighting switch at the battery positive terminal (ne,-ative terminal where the battery positive is cartfied). Push back the rubber shield and then unscrew the cable connector (where fitted). When doing this be sure that the cable does not make contact with any metal part of the fran-ic, otherwise a "fat" spark will indicate that the battery was well charged! When re-connecting the lead, pull the rubber shield well over the connector.

General Overhaul. It is a good plan every l0,000-15,000 miles to entrust the dynamo to a Lucas service depot for dismantling, cleaning, servicing, and lubrication. Lubrication is referred to on page 59.

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The Commutator and Brushgear. The Lucas E3AR and the E3-N dynamos will run satisfactorily for thousands of miles without attention other than occasional inspection of the commutator and brushgear. It is advisable about every 5,000-6,000 miles, to remove the metal cover-band from the dynamo and make a careful inspection.

The Brushes. The brushes must make good electrical contact with the commutator. They must be absolutely clean and able to move freely in

their box-type holders, on holding back the retaining springs and gently pulling the leads and then releasing them. There must also be perfect contact between both the brushes and the copper segments of the commutator; the brush faces in contact with the segments should be uniformly polished. Clean the brushes with a petrol-moistened cloth after removing them. To do this, pull back each brush-retaining spring (see Fig.

25) and remove the brush by pulling on its lead, beincareful to see that the brush pressure spring is clear of the brush holder.

Examine the carbon brushes for wear and unevenness, and true then-t up if necessary. Generally it is best to renew the brushes before serious wear develops, as this prevents sparking, which causes blackening of the commutator and an unsteady charging current. Always replace brushes in their original positions.

If Lucas brushes become so badly worn that it is necessary to remove them, this can easily be done as follows: Release the eyelet on the brush lead by unscrewing the hexagonal nut or screw at the terminal; then, holding back the spring lever out of the way, withdraw the brush from its holder. Renew with genuine Lueas brushes.

The brush springs should be inspected occasionally to see that they have sufficient tension to keep the brushes firmly pressed against the commutator when the dynamo is running. It is particularly necessary to keep this in mind when the brushes have been in use a long time and are very much worn down.

It is unwise to insert brushes of a grade other than that supplied with the

FIG. 25. COMMUTATOR END OF THE LUCAs DYNAMO WITH COVER BAND REMOVED

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dynamo, or to change the tension springs. The arrangement provided has been made only after many years' experience and will be found to give the best results and the longest life. It is really best when the brushes become so worn that they no longer bed down on the commutator, or their flexible leads are exposed on their running faces, to have new brushes fitted at a Lucas service depot, as this ensuris the brushes being properly "bedded."

The Commutator Surface. The surface of the commutator segments should be kept clean and free from oil or brush dust, etc. Should any grease or oil work its way on to the commutator through over-lubrication, it will not only cause sparking, but, in addition, carbon and copper dust will collect in the grooves between the commutator segments.

The best way to clean the commutator is, without disconnecting any leads, to remove from its box-holder one of the main brushes and, inserting a fine dry duster, hold it, with a suitably-shaped piece of wood, against the commutator surface, causing the armature to be rotated by the kickstarter.* If the commutator is very dirty, first moisten the cloth with petrol. The segments should be dark bronze and highly polished.

To Adjust Dynamo Chain. The tension of the dynamo chain which lies behind the primary chain (see Fig. 78) should be checked occasionally, after removing the oil-bath case inspection cap (see page 62). Chain whip with the chain in its tightest position, mid-way between the sprockets, should be approximately 1/4 in.

To make an eccentric adjustment for chain tension, first slacken the strap bolt clamping the dynamo in its housing. Then apply (1945-51) the spanner (Part No.

017254) to the flats cast on the dynamo end-plate, on the left-hand side of the dynamo. Now rotate the dynamo anti-clockwise until chain tension is felt to be correct on passing a finger through the inspection-cap opening. Be careful not to confuse the primary chain with the dynamo chain which lies behind the former (see Fig. 78). Afterwards retighten the strap bolt and again check the tension of the dynamo chain. If found to be correct, replace the inspection cap on the oil-bath chain case (see page 63).

Dynamo Removal. Removal of the dynamo on 1945-51 models is a little difficult, but is greatly simplified on 1952 and later models where the magneto is in front of the cylinder instead of over the dynamo. Full instructions for 1945 onwards are given on page 143.

Compensated Voltage Control (C.V.C.). All A.J.S. motor-cycles incorporate compensated voltage control. The C.V.C. unit consists of a cut-out and voltage-regulator unit in a box beneath the saddle, beside the battery carrier, or (1956-7) in the tool box. It is connected between the dynamo and battery and sees to it that the battery is automatically charged the right amount by varying the dynamo output

* Slow rotation is assisted by removing the sparking plug,

according to the state of charge of the battery and the load imposed on it.

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Current is prevented from flowing back from the battery to the dynamo at low r.p.m. by means of the cut-out which opens. As soon as the r.p.m. rise high enough to enable the dynamo to charge the battery, the cut-out closes and completes the circuit.

In all three lighting-switch positions (see page 24) the dynamo gives a controlled output and thus relieves you of responsibility in regard to charging. The regulator begins to operate when the dynamo voltage reaches about 7.3 volt. During daylight running with the battery well charged and the switch in the "Off" position, the dynamo gives only a trickle charge, and the amrneter reading is unlikely to exceed

1-2 amp. There is no danger of overcharging.

The regulator provides for an increase of dynamo output as soon as the lamps are switched on. The effect of switching the lamps on after a long run with the battery voltage high is often to cause a temporary discharge reading at the ammeter, but fairly soon the voltage falls and the regulator responds, thereby causing the output of the dynamo to balance the load of the lamps.

When the battery is in a discharged state, the regulator increases the dynamo output and restores the battery to its normal state of charge in the shortest possible time.

Do Not Tamper with C.V.C. Unit. The unit is sealed by the makers, as it should not need adjustment once it is correctly set. If, however, the battery (in good condition) is persistently under-charged or over-charged, suspect the C.V.C. unit setting and have it checked, preferably at a Lucas service depot. Note that the C.V.C. unit is retained by self-locking nuts, except on 1956-7 models where it is retained in a sponge-rubber holder in a partition at the rear top corner of the tool box (see Fig. 23). To remove the C.V.C. unit on a 1956-7 model, grasp it between the fingers and thumb of one hand, and gently and firmly pull it away from the sponge-rubber holder.

As may be seen in Fig. 26, the four terminals of the C.V.C. unit are clearly marked by the letters F.A.D.E. Leads from the F and D terminals are attached to similarly marked terminals on the dynamo. The terminal marked A is connected to one of the ammeter terminals, and the terminal marked E is earthed.

Fig 26. CONNEXIONS TO COMPENSATED VOLTAGE-CONTROL UNIT

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