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1. 08:18 PM - Re: Revmaster 'dual' alterantors (dj_theis)
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| Subject: | Re: Revmaster 'dual' alterantors |
>>Without talking to the designers, it's
>>difficult to KNOW the original thinking behind the
>>design.
I've spoken to Joe Horvoth a couple of times, before and just after purchasing
my engine. I spoke to him at least once regarding the alternator and ignition
system. Joe is not a particularly "chatty" fella but I think he is rightly proud
of his design. His innovation in the design and improvements of the VW are
truly impressive. Joe is clearly gifted when it comes to mechanical design and
engine building. Unfortunately, I think the electrical systems were done by
a hired gun and not by Joe directly (an unconfirmed rumor I am starting).
As noted in the earlier posts and comments, Joe has strongly recommended not to
run both alternator sides at the same time and has also strongly discouraged
the use of anything but traditional lead acid (wet) batteries. I've never heard
him go into any detail on the reasons behind these recommendations. I should
have asked when I visited him a few years back.
>>So take a peek at the simplified proposal diagram.
>>Hook the two Revmaster windings in series-aiding
>>and bring out the center-tap. Connect in full wave
>>configuration with only TWO junction rectifiers.
I like the approach and two questions come to mind:
How well the current will be equally divided by the two windings?
This is half wave rectification, right?
I have not spun my engine yet but from examination of the windings I expect to
see the two PMAs "IN PHASE" and as noted, single phase, not polyphase. Does this
configuration change the expectation of roughly evenly divided current? If
the two PMAs were out of phase by 180 degrees (which is possible if my talents
with the "right hand rule" are off abit) I assume the center tap would not
operate the same, if at all.
I have to pull my engine once more before I start it (hopefully, yet this fall)
and will examine the windings on the PMAs closely to convince myself of the phase
relationship between the two halves.
One final note. I've thought about this a little (clearly not as much as Bob).
I plan on installing thermo-couples as close to the center of each stator base
as I can. My thought is to run the engine as deigned, with OEM regulators and
running one halve at a time. I am planning on a Odyssey battery (PC680) with
added (2) shunt resistors in the charge circuit to increase the load seen by
the PMAs. I plan on trying to identify what the conditions are that lead to
the high temperature in the PMAs. I hope to be able to install the TCs close
enough to the windings to obtain a warning before they overheat. I think the
expected meltdown of the "enamel" insulation is a bit over 200C. Can anyone
confirm?
In the long term, I'd like to install something like the CCCV regulator mentioned.
Is there actually such a regulator designed and available for a PMA on an
OBAM aircraft?
Dan Theis
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Scratch building Sonex #1362
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http://forums.matronics.com/viewtopic.php?p=498148#498148
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