The function of the RR. The voltage supplied by the alternator increases with the engine speed. It must, therefore, be limited to a specific value, usually 14 to 15 V, to avoid causing damage.
This voltage is an alternative, as in a power outlet. It must be rectified in DC voltage (with a + and a -), the only one that can be exploited by the equipment of the bike, starting with the battery. All this electronic alchemy is done in one element: the regulator-rectifier, or RR.
Preliminary checks. To test the RR, it is imperative to have put out the alternator and the battery (NdSR: LINKS to articles? Or see MM No. XX). Check the cleanliness of the connections firmly: the main multipin, plus the black wire (ground), sometimes caught under one of the RR screws (Step 1).
The suspect RR must then be tested itself. Some models, once “grilled,” have specific symptoms of overheating (Step 2). An electrical check confirms the harm.
As a reminder, the RR is suspect if the motor running voltage exceeds well 15 V. In this case, check that the “more after contact” arrives at the RR: here is the green wire (Step 1). Conversely, if the voltage measured at the battery remains low, it will sometimes be correct, taken with the red wire directly at the output of the RR.-In this case, it is only a problem of wiring.
If nothing is done, go to the RR’s internal tests with a multimeter, as described in the service manual (Revue Moto Technique or other). Even without being an expert in electronics, it is sufficient to perform the simple measurements mentioned there (Step 3). Once all these points are verified, you will know for sure if the “regular” in HS.
The tests described here concern the regulators-rectifiers for three-phase generators with permanent magnets, the most widespread.
Test the voltage regulator
1 The connections are a weak point of the charging circuit. They must be perfectly clean so as not to distort the tests. Also, a weak crossing point causes local overheating.
2 The components of the rectifier-regulator are embedded in a protective resin, here in good condition, but often blistered or cracked prominently after a fatal overheating.
3 The state of the components is tested by merely disconnecting the connection pin and applying one by one the measures described in a technical review. Smooth, even if you do not know electronics.
Before calling into question the regulator-rectifier, rigorous control of the battery and the alternator is essential.
Never tamp down anything (rain pants, etc.) against the regulator: it could not be appropriately chilled.
The poor condition of the connections is one of the most common causes of load failures.