Thursday, September 8, 2016

Voltager Rectifier/Regulator

Ducati Voltage 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. -
After the storm
We survived the Hurricane. I was pleased to find Sally in great shape safely secured in her covered tie down spot. In general, this turned out to be more of a giant squall line for the Tampa area then a Class 1 Hurricane, but there was significant flooding and northern Florida had numerous downed trees and power lines. We were safe.

A subsequent flight after the storm went well, except for a persistent red generator light. Having had these symptoms before, I suspected a failed Voltage Regulator. I ordered a replacement from US Sport Aircraft and planned to spend some time over the Labor Day Holiday to replace the failed part.

It is a relatively simple job made complicated by the attachment design. Two through bolts hold the Voltage Regulator to the firewall. If I had eight foot multi-hinged arms I could hold the bolt head inside the cockpit while loosening the nut in the engine compartment. I don't. Or, I could get some help, but my lead assistant was busy at the mall taking advantage of Labor Day bargains. I would be solo on this one.

First, how to get to the bolts. Enter the pilot's side, and keeping your left leg on the wing, kneel onto the pilot's seat. (Advance throttle and choke to full forward.) Slowly roll your shoulders onto the copilot's seat and using any available handhold force your body past the stick close to the rudder peddles.  (Caution: Make sure all tools and supplies are prepositioned for easy reach.)

The trick is: Vice Grips and masking tape. By reaching under the copilot panel, find the bolts holding the voltage regulator and tightly clamp in place with the vice grips. Now, tape the tools to the firewall. (If you skip this step the vice grips will rotate with the nut until they interfere with something else under the panel. Not good.)

Now, get out anyway you can. (I suspect it won't look elegant, but that's just me.) Remove and replace the part. Easy. Now retrieve the vice grips. Not so easy.

The test flight went well. Green generator light the whole time. However, I did have a strange radio feedback on my initial call for taxi. It went away after a few minutes. Everything seems to be just fine, for now.

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