The purpose of this test is to assess the controlled output of the alternator in relation to electrical load on the battery.
Connection for diagnostic work will vary dependent on application.
Technicians should whenever possible gain access to the test circuit without damage to seals and insulation. If this is not possible then make sure appropriate repairs are completed.
General connection advice
PicoScope offers a range of options within the test kits.
Dependent on difficulty of access, choose from:
Testing sensors and actuators (to include relevant circuit/connectors):
Note; the orientation of the current clamp relative to the wire will determine whether it has a positive or negative output. If a live waveform does not appear on your screen, or appears to be inverted, try reversing the orientation of the clamp.
These known good waveforms have the following characteristics:
A stable battery voltage (Channel A) around 14.5 V, with no spikes or significant ripples.
An AC waveform (Channel B) with a DC average around 48 A and even peaks and troughs.
The function of the alternator is to provide energy to power any electrical systems operating when the engine is running. Furthermore, the alternator must have sufficient output to replace charge within the battery after cranking and engine start.
Increases in alternator output have a number of adverse effects on vehicle operation:
An alternator with a faulty control regulator can increase voltage proportional to RPM, causing damage to the battery and to connected electrical systems.
Symptoms / causes of a faulty alternator;
This help topic is subject to changes without notification. The information within is carefully checked and considered to be correct. This information is an example of our investigations and findings and is not a definitive procedure. Pico Technology accepts no responsibility for inaccuracies. Each vehicle may be different and require unique test settings.
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