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connection in the cranking circuit should be bridged by the voltmeter connections. A reading of the voltmeter will indicate the defective connection.
Should the voltmeter indicate a normal voltage from the heavy terminal on the rear of the generator to the ground when the starting pedal is depressed and still the starting motor makes no effort to crank the car, trouble must exist within the generator, such as the motor brush not coming in contact with the motor commutator or dirt or grease on the commutator preventing electrical contact. This could also be caused by trouble in the armature windings, but is very improbable, and can be tested as described.
TROUBLES IN DYNETO SYSTEM
If Dyneto Will Not Start
Do not leave the switch on “start." Turn on lamps, if they burn brightly, try starting again and watch lamps; if they do not drop at all in candle power, it is quite likely that there is an open circuit in the starting wires, switch contacts, terminals or brushes. Be sure that the brushes are not worn out, are free in the holders, and that springs are in condition to press them firmly against commutator.
If, with switch on “START,” lamps drop slightly in candle power, and the Dyneto does not start, the trouble may be due to loose connections, rough or dirty commutator, brushes worn out or not well fitted to the commutator, weak brush springs, grounded or defective armature or field windings. If Lamps Burn Very Dimly or Not at All
If lamps burn very dimly or not at all, when switch is moved to “START," the battery is probably discharged or defective. See battery instructions. If Dyneto Starts But Runs Too Slowly
Look for high resistance in main circuits, too small wire, loose terminals, bad joints, poor switch contacts, rough commutator, short brushes without sufficient spring tension; also look for weak
Fig. 272.-Diagram Showing Wiring of Dyneto-Entz Starting and Light
battery, partially discharged, possibly due to grounds, leaks, unnecessary use of lights when engine is not running or continuous cranking when motor will not “pick up” because of poor carburetion or ignition. If Dyneto Starts But Will Not Generate
The trouble will probably be found in an open shunt field circuit. This circuit may be traced as follows (see Fig. 272): From negative pole of battery to post 1 through shunt field on Dyneto to post 3 S HF on starting switch, through switch to SER F, post 4 to positive battery. This circuit may be tested out independently of the main circuit by removing wire from post 2, so as to cut out armature circuit, and setting the starting switch on “START.” If the circuit is complete a bright spark will be made when wire is removed from post 3. If no spark occurs, look over all wires and connections, and an open circuit will be found. If Dyneto Does Not Generate Enough Current
First be sure that the battery is in good condition, and that it utilizes the current actually delivered to it by the generator. (See battery instructions.) If battery is all right, go over shunt circuit as in last paragraph. Be sure that there are no loose connections, and that the commutator is clean and smooth; that the springs keep the brushes pressed against the commutator properly. If an ampere meter is available, connect it to one of the wires leading to the battery. The amount of current that should be generated at various speeds is specified above. Grounds, Short Circuits, Open Circuits in Lamps and Wire
These troubles are quite common when the wiring is poorly done. Grounds and short circuits often occur in wires not protected by suitable conduit and good heavy insulation, especially when wires pass around sharp corners, over bolt heads, etc. Grounds are also sometimes found in switches, lamps and connectors.
Open circuits may be due to blown fuses, bad joints, poor wiring, loose connections. They are also found in connectors and lamp sockets.
TROUBLES IN BOSCH RUSHMORE SYSTEM
The following instructions regarding the location of trouble in the Bosch-Rushmore starting and lighting system are taken from the Marmon instruction book : 1. No Lights Obtainable, Car at Standstill
If lights are obtainable when engine is running, but no lights are available when the engine is at a standstill, this condition indicates that the battery is either in a totally discharged condition, that the connections to same are loose, or that No. 3 connection to the control box is not making proper contact, or the fuse between positive terminals of the battery and ground is blown or the ammeter shunt is open circuited. If the battery is found discharged, it must be given a charge from an external source. If the connections are loose, re-establish the integrity of the joints. If the fuse is blown, it is necessary to test out the different circuits with either a bell or test lamp before putting in a new fuse. The fuse may have been blown because of a short circuit in one of the circuits and merely replacing the fuse without correcting the faulty circuit would be of little avail. Never use a piece of copper wire in place of a fuse. Always have sufficient fuses for replacement on hand. To determine whether the ammeter shunt is blown or not place the meter handle in the left hand or voltage position. If voltage is obtained move the handle to the right hand position, which is the ampere position. Place the left hand lighting switch handle in No. 1 position; if the shunt is burnt out there will be a violent fluctuation to the left. If this condition exists it will necessitate removing the cover of the control box, uncoupling the two wires that are connected to the connections on the meter and then remove the screws that hold the meter in position. It is necessary to test the wiring thoroughly to locate a ground which might exist and which may have caused the ammeter shunt to blow out. After the ground is located and removed the two wires that were previously connected to the engine can be joined together by means of a small bolt, as this will allow the system to be used while the meter is being repaired. 2. No Lights Obtainable Under Any Conditions.
This condition could be caused by any of the foregoing defects, with the addition of No. 1 and No. 2 cables (see Fig. 234) making poor connections either at the dynamo or control box. When making up or replacing terminals used on the cables, use the special wrench supplied with these outfits. It is not necessary to make these tight, as it is only required to tighten the nuts until no more play can be felt by pushing the wire in and out of the nut.
3. Individual Circuits.
Bulb filament burnt out; bulb base not making proper contact; cables supplying this circuit loose; the remedy for this is obvious. 4. Lights Flickering.
Primarily due to either improper brush contacts, dirty commutator, or loose No. 1 or No. 2 leads, which results in the automatic relay openings and closing with great rapidity. In order to eliminate this, it is necessary to loosen the top screw of end cover of dynamo and turn cover to the left, as far as it will go. This will expose brush holders and commutator. Brushes can be removed by lifting up springs and pushing them to one side. Remove whatever dirt may be on the brushes, in order that they may have a free sliding fit in the brush holders. The sticking of the brushes may have caused the commutators to have become roughened. This can be cleaned by means of fine sandpaper, not emery paper. Never attempt to use other brushes than those supplied by the Bosch Company. If the flickering is intermittent, it is caused by loose connections on the battery side of the system. 5. Lights Dim (Individual Circuit).
Poor lamp contact or poor cable contact; remedy obvious. 6. All Lights Dim (Car Standing Still).
Battery partially discharged; partial ground or short circuit. First determine the condition of the battery as cited under “battery” heading. If this is found to be 0. K., test each individual circuit for ground. This can be done by disconnecting them all at the control box, and replacing them one by one, and note at which circuit the lights dim. This will be the circuit that the trouble exists on, and the cable terminals and cable itself should be thoroughly examined. 7. Lights Dim (Engine Running).
Dynamo not operating with a partially discharged battery. Dynamo and battery condition 0. K. with a heavy ground or short circuit on system; starting switch not having returned to the off position. To remedy, proceed as under heading "no lights obtainable.'