Rotax regulator rectifiers, why and how are regulator rectifiers are used.

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What is the purpose of the regulator rectifier?  Why do they call it a regulator rectifier?

The regulator slash rectifier performs two tasks. Power coming out of your Rotax engine is AC power. The two yellow black wires coming from your magneto each have a different "phase". The regulator/rectifier converts this from a 3 phase AC power to a single phase DC.

The magneto is always trying to put out the same amount of power, this creates a problem when the battery is fully charged, or there is no heavy load on the system. A lot like a tap filling a pail of water, if something is drawing water from the pail at the same rate it is entering it will not over flow. But if the water keeps coming in with none being taken out, it will over fill,  - thus the battery over charges.

The regulator rectifier prevents this by taking the excess voltage and and converting it to heat to keep the system with acceptable limits.

For the system to work properly, the ground on the plane MUST be good. If the ground is poor the charge that would normally be going into the battery, now goes into the rectifier and possibly other electrical components connected into the system. This of course can cause failure of these components.

For this reason it is imperative that all grounds be checked for corrosion.  This can be caused by copper wire connected to a steel airframe, two dissimilar metals will act on each other, add rain, battery acid, vibration and you have copper sulfate which is that blue powder you find on your battery terminals.

The battery is 12 volts DC - and is being charged by the use of the regulator/rectifier it's purpose in the system to to provide a "sink" for the system, reserve power when the engine is at an idle, and a power source for starting and operating equipment when the engine is not running.
How to check your regulator rectifier in pdf format

Rectifier Wiring diagrams

Rotax offers two rectifiers for their two stroke engines 

866 080  
Single Phase Regulator
Used on 377/447/503/532 with points ignition Wiring Diagram


264 870
Phase Regulator recommended for 503/582 DCDI Wiring Diagram


Rotax 912 magneto, Rotax 912 magneto generator, Rotax 912 charging system.

965-347  912/914
Voltage Regulator Factory replacement unit for 912-914. Converts internal generator A/C output to D/C voltage.
Rotax 912/914 wiring diagram and installation


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