Measurement method
The condition under which the measurement is made
Oscillogram of the voltage of a working ignition system
Generator voltage measured at the point
Examples of voltage waveforms of a faulty generator
Attention! Generator voltage measured at the point «IN», can change in waves, as shown in the figure. This undulating change is due to the operation of the voltage regulator caused by fluctuating load current and is not an indication of a generator failure. If the amplitude of the voltage fluctuation reaches a significant value (approximately 2 V or more at idle), then this indicates an open circuit in the output circuit of the generator due to the burnout of the fusible link between the output «IN» and rechargeable battery. The generator set in this case is serviceable.
Examples of voltage waveforms of a faulty generator
Attention! Screen size (see table) can be changed by changing the gain of the oscilloscope.
Waveform analysis is best done with the generator running under load (while the voltage regulator does not interfere with measurements). (Measurements can be made with the headlights on.)
Check the condition of the battery warning light (on/off). Completely check the power supply system.