Page 172 - CTS - Mechanic Diesel - TP

MECHANIC DIESEL - CITS

Testing of solenoid switch
Electrical tests
1 Check that both contact close when the following voltage is applied to the solenoid winding.
2 Subject the switch to a test of a few seconds duration at twice the normal voltage to ensure that the trigger
operation is satisfactory. Any faulty assembly or rounding off of the trigger or catch plate will cause the catch
to trip.

3 When these tests have been successfully completed, the commutator end cover should be carefully fitted and
the machine subjected to insulation test.
Insulation test

Using the probes connected to a 230v max. supply and in series with a 15watt lamp of suitable voltage, check the
insulation of the machine by touching probes on terminal B and frame. If the lamp lights, the insulation is faulty.
Assembly and Adjustment of starter motor
1 Hold the armature (8) in an armature clamping device, or in a vice fitted with soft metal or wood to clamps

2 Liberally smear the spring and thrust washer on armature plunger (28) with grease. Insert the plunger into the
bore of the armature and tighten plunger retaining nut (32) using the appropriate tool.
3 Insert pressure plates, back ring and shim washers into clutch outer race (6)

4 Lightly smear initial pressure springs with grease and place them in their holes in clutch inner race, over that
guide pin. Each springs should be inserted with it largest diameter first.
5 Lightly grease clutch plates 38 and place them on the splines of the clutch inner race, taking care to it them
alternatively bronze and steel. Fit steel plate first so that it take the pressure of the clutch springs.
6 Assembly clutch inner race together with clutch plates and springs in the clutch outer race.
7 Grease pinion spring (37) and side it on the armature shaft.
8 Grease bore of pinion (2) and insert rubber sealing rings and shims.

9 Insert pinion into drive end shield (40). In order not a damage the felt lubricating pads, the pinion should be
twisted in the direction of the spiral of the pinion thread whilst the lubricating pad is lifted by one finger from
inside the casting. Also a suitable should be used along with the pinion so a not to damage the oil seal

Note: Before fitting a new shield ensure to remove the protective fibre pad which is put there to
prevent ingress of foreign materials when the DE shield assembly is stored for service sales.

10 Slide pinion and drive end shield on the armature shaft. Push the pinion forward and rotate it until its thread
engages in the internal thread in the clutch inner race. Hold it in this position and replace shims, washer, and
nut. Make sure that the shim located over the shoulder of the shaft and tighten the nut securely. After the nut
has been tightened the pinion must be capable of a small axial movement on the armature shaft.

11 Where the facilities exist, the slipping torque of the clutch should now be adjust as follows:
• Clamp the armature to the bench using a clamp bracket, or in a vice, the jaws of which are protected by
aluminium, wood or soft brass shield and fit sockets. A standard torque spanner calibrated to 150 lb. ft. and
half inch square drove shaft should be fitted to the appropriate torque sockets and the applied torque will
be shown on the calibrated scale.

• Adjust the clutch to slip at 100-115 lb.ft (13.8-15.9 kgm). This should be done by removing adding shims
between the clutch plates and the back plates. The shims are made in two thickness 0.1 and 0.15 mm
Adding shims will increase the slipping torque and vice versa

• Slip the clutch about 10 times and then adjust the clutch to slip at 80-100 lb.ft(11.06 to 13.8kg
• If torque socket is available only for one type of pinion (say 11 teeth) to check starters having other pinion
the following procedure is to be adopted

• Fit a eleven tooth pinion on the starter and then use the correct socket. Carry out setting of clutch as given
above. After checking and resetting place the original pinion in starter.

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CITS : Automotive - Mechanic Diesel - Exercise 9.3