David,
Using a resistor to protect against an overvoltage event is unusual.
R and B are indeed tied together internally and are the output of the regulator.
C is the regulator control and voltage sense input, so while it needs to see
the bus voltage in normal operation, you might want to be able to control it
although if it is disconnected from bus voltage, it will cause the regulator to
turn full on and potentially cause damage. I mention this only so you understand
how the regulator operates.
We all use the word regulator, but actually these devices are regulators and
rectifiers
combined. They take the AC output from the Rotax and rectify it to DC
and regulate the DC voltage to roughly 14 volts. Again mentioned only for
clarity.
I think the best solution for you is to purchase a B&C AVC-1 regulator. It is
designed to control the Rotax permanent magnet alternator/dynamo. It has built
in over voltage protection, adjustable output voltage and warning outputs.
It also features properly sized heat sinks for the internal components. All the
details are here:
https://bandc.com/wp-content/uploads/2022/12/AVC1_Technical_Manual_XB100-2-TM_12-8-22.pdf
If you want to use your Powermate regulator, Id suggest using AeroElectric Z-16
diagram as a starting point. It is somewhat innovative as it switches the AC
from the alternator/dynamo before it goes to the regulator thus eliminating
switching spikes. It also provides a safe overvoltage feature. I have used
this in my Europa for over 1000 hours with no problems. Here is a link:
http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z16M.pdf
Another consideration of your Powermate, is that many of the common
regulators/rectifiers
like the Ducatti supplied by Rotax and the Chinese regulators used
by many are actually intended for use in lawn mowers. They often are poorly
constructed
and have limited current capacity. Ducatti units have a history of vibration
failure and component failure when asked to carry over 10 amps continuously.
Your diagram appears to have modest current requirements, probably less
than 10 amps if the lights are all LED. My 914 Europa requires about 8 amps
in cruise with similar equipment except no autopilot.
Hope this helps. Feel free to ask more questions.
Jim Butcher
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=512773#512773
|