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Jim,
The Odyssey documentation recommends charging their batteries at between
14.1 - 14.7 volts, and to never exceed 15v. I have read that automotive
regulators are set at the high end to keep the typical auto battery
charged when making short trips. Our situation is just the opposite,
our trips tend to be long trips. I prefer to set mine toward the low
end of the manufacturer's specified range, at 14.2v-14.3v. In winter,
it doesn't hurt to dial it up a few tenths to compensate for the colder
temps. Mark S. -----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Jim Sower
Sent: Saturday, September 10, 2005 2:29 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Overvoltage control (help Ed A)
No. It is designed to output 14.4 - 14.7V and that's what it does. I think adjustments are for units that wander a lot and won't hold a
setting.
Why would I want to adjust what's right (Harvey's Second Law) ... Jim S.
Mark R Steitle wrote:
Is your internally regulated alternator adjustable? -----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Jim Sower
Sent: Friday, September 09, 2005 2:32 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Overvoltage control (help Ed A)
If my crowbar overvoltage opens the B+ circuit, there's NO current flowing out of the alternator. Absent current, there can be no heat generated. The field can go to max output, there will be high voltage at the B+ terminal, but no heat generated. Sounds to me like a bogus concern. I think the key issue is "... Nuckolls expressed dislike ..."
and no further support is "needed".
Still looking for a "real" reason ... Jim S.
Mark R Steitle wrote:
Jim,
I first explored this issue after Bob Knuckols expressed a dislike of
internally regulated alternators...because they can fail in such a way
that you cannot shut them down. Yes, you can interrupt the "B" lead,
but this will not shut down the alternator. I imagine it could get
hot
enough to self-destruct and possibly catch fire. The modification I use removes the internal regulator assembly and
puts
a direct (external) feed line to one of the brushes. The other brush
is
tied to ground. Nothing else is connected to the field. With this
arrangement, can you explain how removing power from one of the
brushes
will allow the alternator to continue producing power? I've tested my
modified alternators with the engine running and it does in fact stop
producing power when I cut the power to this lead.
Another benefit to an external regulator is that you can precisely
adjust the voltage, provided you use an adjustable regulator. Mark S. -----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On
Behalf Of Jim Sower
Sent: Thursday, September 08, 2005 5:31 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Overvoltage control (help Ed A)
I've always been puzzled why folks would go to all the trouble of disabling a perfectly good internal regulator so as to install an external unit. If the Field circuit gets somehow internally shorted
to
the output circuit, the alternator is going to run away and create an over voltage condition. In that event, there's no way that turning
off
current to the Field is going to help you. Other than a short described, I don't know how an over voltage can occur. So my question
is: is an internally regulated system all that much more apt to have
an
over voltage type failure, and if so why? I've had lots of trouble
with
externally regulated alternators, very little with internal
regulators.
My crowbar over voltage system is bullet proof. It's the only scheme that prevents damage caused by an internal short in the alternator.
What, exactly, is the big attraction of external regulators? ... Jim
S.
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