Generator Rectified Voltage Waveform
I – generator is OK; II – the valve is broken; III – break in the valve circuit
The oscilloscope allows you to accurately and quickly check the generator's serviceability and determine the nature of the damage based on the shape of the generator's rectified voltage curve.
To check, rotate the generator rotor at a frequency of 1500–2000 min⁻¹, powering the excitation winding from the battery, but disconnect the battery from the "30" terminal.
If the valves and stator winding are in good condition, the rectified voltage curve has a sawtooth shape with uniform teeth.
If there is a break in the stator winding or a break or short circuit in the rectifier valves, the shape of the curve changes dramatically: the uniformity of the teeth is disrupted and deep depressions appear.