Perkins 4.99 - Dynamo Servicing; Dynamo Routine Maintenance and Performance Data

2. Routine Maintenance
(a) Lubrication
Every 4,000 miles (6,000 km) or 150 running hours,
inject a few drops of high quality S.A.E.30 engine oil
into the hole marked "OIL" at the commutator end
bearing housing (Refer to Fig. Q.2).
(b) Inspection of Brushgear
Every 72,000 miles (108,000 km) or 2,700 running hours,
the dynamo should be removed from the engine and
the
bushgear inspected by a competent electrician.
( C) Belt Adjustment
Every 4.000 miles (6.000 km) or 150 running hours. in-
spect the dynamo driving belt, and if necessary. adjust
to take up anv slackness by turning the dynamo on its
mounting. Care should be taken to avoid overtightening
the belt (see Page M.1).
3. Performance Data
The cutting in and maximum output speeds quoted
below are production test figures and refer to cold
machines with brushes only partly bedded.
Model C40-1.
Cutting-in Speed.
1450
rev/min (Max.) at 13.0 dynamo volts.
Maximum Output.
22 amp at 2250 rev/min (Max.) at 13.5 dynamo volts
and a resistance load of 0.61 ohms.
Field Restistance.
6.0 ohms.
4. Servicing
Testing
in Position
1. Inspect the driving belt and adjust if necessary.
(Refer to Page M.1).
2. Check the connection on the commutator end
bracket. The larger connector carries the main
dynamo output, the smaller connector the field
current.
3. Switch off all lights and accessories, take off the
cables from the terminals of the dynamo and con-
nect the two terminals with a short length of wire.
ELECTRICAL EQUIPMENT -Q.S
LUBRICATOR IN COMMUTATOR END BRACKET
FELT RING
RETAIN ER
INJECT _-----\_..:::..:.
OIL HERE
FELT RING
POROUS
BRONZE BUSH
02
4. Start the engine and set to run at normal idling
speed.
5. Clip the negative lead of a moving coil type volt-
meter,
(calibrated 0-20 volts) to one dynamo ter-
minal and the positive lead to a good earthing point
on the yoke.
6. Gradually increase the engine speed, when the
voltmeter reading should rise rapidly and without
fluctuation. Do not allow the volt meter reading to
reach 20 volts, and do not race the engine in an
attempt to increase the voltage. It is sufficient to
run the dynamo up to a speed of 1,000 rev/min. If
the voltage does not rise rapidly and without
fluctuation the unit must be dismantled for internal
examination.
Excessive sparking at the commutator in the above
test indicates a defective armature which should
be replaced.
NOTE: If a radio suppression capacitor is fitted
between the output terminal and earth, disconnect
this capacitor and re-test the dynamo before
dismantling. If a reading is now given on the
voltmeter, then the capacitor is defective and must
be replaced. If the dynamo is in good order,
MODEL C40~1 GENERATOR. DISMANTLED
OUTPUT
'TERM I ""'L 'D'
03
POROUS
BRONZE
BUSH
BOLTS
flSRE
THRUST
WASHER
YOKE
RETAINING
PLATE.
SHAFT COLLAR
CUP
FELT
RING
SHAn
KEY
ORIVE END
BRACKET
SHAFT
NlfT
PULLEY
SPACER