COUPLING AS-FLEXIBLE 1470085 - Caterpillar

class="catalog_a_num" href="https://avspare.com/spare/caterpillar/7g7889/">7G7889 ... 5.7 to 7.1A at 12V Divide the voltage from Step 2 by the resistance of the field coil winding (as shown in specifications). This also gives the field current as seen on ammeter (A) for a correctly operating system.If ammeter (A) indication is zero amps, the rectifier, field coil or regulator are open. If ammeter (A) indication is too high, it is possible the field coil is shorted.4. If the measurements in Steps 2 and 3 are correct, go to Step 5. If they are NOT correct, the alternator and/or regulator are bad.5. Adjust VPS to the turn-on voltage as measured in Step 2. Slowly increase the voltage until ammeter (A) indicates zero amps. Write this voltage down as turn-off voltage.6. When correctly operating, the difference between the turn-off and turn-on voltages is no more than 0.3V. A larger value indicates a regulator malfunction. Also, ammeter (A) should drop sharply to zero amps. If not, the regulator is faulty.7. If the alternator and regulator meet all test requirements and there is still a problem, do the additional component tests that follow.Capacitor Test
Capacitor
(1) Housing. (2) Ring terminal.1. Remove the capacitor from the alternator.2. Place and hold ring terminal (2) on housing (1). This discharges the capacitor. Each time this test is done, discharge the capacitor.3. Put the multimeter on the 20M resistance (Ohms) scale. Connect a multimeter lead to ring terminal (2). Connect the other multimeter lead to housing (1).4. When correctly operating, the resistance is very low for a short period of time and then it should stabilize above 100 000 ohms (meter reading 0.10 or greater).5. If the reading is not correct, replace the capacitor.Field Coil Tests
Field Coil
(1) Leads. (2) Housing.Field Coil Continuity Test
1. Put the multimeter on the 200 ohm resistance (Ohms) scale. Touch and hold a meter lead on each lead (1).2. For correct operation, the resistance value is: 3T6352 ... 6.3 to 7.3Ohms5N5692 ... 8.5 to 9.5Ohms7G7889 ... 1.7 to 2.1Ohms3. If the resistance is not correct, the field coil is open or shorted. Replace the field coil.Field Coil Ground Test
1. Put the multimeter on the 20M resistance (Ohms) scale. Touch and hold one meter lead to one coil lead (1). Touch and hold the other meter lead to housing (2).2. For correct operation, the resistance is 100 000 ohms or greater (meter reading 0.10 or greater).3. If the meter reading is LOW, the field coil is grounded. Replace the field coil.Stator Tests
Stator
(1) Leads. (2) Frame.Stator Winding Continuity Test
1. Connect the meter leads between each pair of stator leads (1) for a total of three readings.2. For correct operation, all three readings are approximately the same.3. If any two readings differ by 0.10 ohms or more, replace the stator.Stator Winding Ground Test
1. Put the multimeter on the 20M resistance (Ohms) scale. Check each stator lead (1) for a short to ground. Connect one meter lead to a stator lead (1) and touch the other meter lead to stator frame (2). Repeat