The starter motor is checked in idling and full braking mode. Idle settings (speed and current consumption) allow you to judge the build quality and mechanical failures. Presence of defects (tight rotation of the shaft in bearings, etc.) causes an increase in power consumption during idling, as a result of which the idling current increases. and the armature speed will drop below normal. In idle mode, electrical faults also appear. Thus, an increase in current strength and a decrease in the armature rotation frequency may be the result of a mechanical short circuit of the armature winding, and an interturn short circuit of the excitation winding leads to an increase in the armature rotation frequency. Electrical faults are detected in full braking mode. Full Brake Options (torque, current consumption) allow you to determine the condition of the electrical part of the starter. With poor contact between the brushes and the commutator, the current consumption and torque are reduced below normal. The short circuit of the armature windings on the case or the short circuit in the excitation winding leads to a decrease in torque with an increased current consumption against the norm.
The connection diagram during the test corresponds to the starter switching circuit on the car (pic. 8-7). Starter 1 is turned on by closing the contacts of switch 5. In this case, power is supplied to the output «50» windings (windings) the traction relay and its contacts close As a result, the voltage measured by the voltmeter 2 through the ammeter 4, starter output «30» and closed contacts of the traction relay is fed to the starter motor. The voltage applied to the starter between the starter relay output and its housing, when tested at idle, should be 11.5 V. During the test, the starter current and armature speed are recorded. Instrument readings are taken after the starter has been idling for 20-30 s. The test is considered passed if the consumed current is not more than, and the rotational speed is not less than the rated values.
Pic. 8-7. Starter test scheme:
1 - starter;
2 - voltmeter;
3 - direct current source;
4 - ammeter;
5 - switch.
It is advisable to carry out the test in idle mode with the brush-collector assembly open, making visual observations of it. In this case, there should not be noticeable movement of the brushes in the brush holders, the presence of which indicates an increased beating of the collector or protrusion of insulation above its surface.
The starter test in full braking mode is carried out at a certain supply voltage (tab. 8-4). Moment. developed by the starter must be at least a certain value, and the current must not exceed a given value. The circuit that is assembled when checking the starter in full braking mode is the same as when checking in idle mode. Additionally, a load device equipped with a torque meter is required.
Visitor comments