Connection diagram for testing the starter on the stand
1 - rechargeable battery; 2 – ammeter with shunt for 1000 A; 3 - switch; 4 - rheostat; 5 - voltmeter with a scale limit of at least 15 V; 6 - starter
If there is any doubt about the efficiency of the starter, it is necessary to check it on the stand. Connecting wires to the current source, ammeter and contact bolt of the starter traction relay must have a cross section of at least 16 mm2.
The temperature of the starter during checks should be (25±5) °C, and the brushes are well lapped to the collector.
Health check
1. Closing switch 3 (see fig. Connection diagram for testing the starter on the stand), when the voltage of the current source is 12 V, turn on the starter three times with different braking conditions. For example, with braking torques of 2, 6 and 10 Nm (0.2; 0.6 and 1 kgf·m).
2. The duration of each starter activation should be no more than 5 s, and the intervals between starts should be at least 5 s.
3. If the starter does not rotate the ring gear of the stand or its operation is accompanied by abnormal noise, then disassemble the starter and check its parts.
Full brake test
1. Slow down the ring gear of the stand, turn on the starter and measure the current, voltage and braking torque, which should be for the starter 35.3708, respectively, no more than 550 A, no more than 7.5 V and no less than 13.7 N·m (1.4 kgf·m).
2. For the ST-221 starter, the current should be no more than 500 A, and the voltage no more than 6.5 V.
The duration of the starter activation should be no more than 5 s.
3. If the braking torque is lower and the current strength is higher than the specified values, then the interturn short circuit in the stator and armature windings or the short circuit of the windings to ground may be the reason for this.
4. If the braking torque and current consumption are below the above values, then the cause may be oxidation and contamination of the collector, severe wear of the brushes or a decrease in the elasticity of their springs, brushes hanging in the brush holders, loosening of the stator winding leads, oxidation or burning of the contact bolts of the traction relay.
5. At full braking, the starter armature should not rotate; if it does, the freewheel is faulty.
6. To troubleshoot, disassemble the starter and replace or repair damaged parts.
Idling test
1. Disengage the ring gear of the stand from engagement with the starter gear.
2. Turn on the starter and measure the current consumed by it and the speed of the starter armature, which should be no more than 60 A, respectively (35 A for ST-221 starter), and 5000±1000 min–1 when the voltage at the starter terminals is 11.5–12 V.
3. If the current strength and rotational speed of the armature shaft differ from the indicated values, then the reasons may be the same as in the previous test.
Checking the traction relay
1. Install between restrictor ring 3 (see fig. Starter 35.3708) and gear spacer 12.8 mm thick and turn on the relay.
2. Check the switch-on voltage of the relay, which should be no more than 9 V at ambient temperature (20±5) °C.
3. If the voltage is higher, then this indicates a malfunction of the relay or actuator.