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From: Mark R Steitle
Sent: Tuesday, January 24, 2006
1:22 PM
To: 'Rotary
motors in aircraft'
Subject: RE: [FlyRotary] Re: Two
Alternators?
Bill,
I haven’t done a wirebook on my a/c
as yet, but it is based on the Z-14 architecture. (I tried to attach the
Z-14 pdf, but it was too large and so it bounced. I will send it to you
directly.) Like I said earlier, the only real difference is that
I’m using Tracy’s
EC-2/EM-2 rather than mags. These are wired per Tracy’s instructions, and directly to a
CB on the “Flight Critical Bus”. If you haven’t done
so, I recommend you read the article I referenced earlier on charging system
design by Bob Nuckols of the Aero-Electric Connection. He discusses the
pro’s and con’s of the different architectures. He describes
the dual alt, dual battery system as the mother of all electrical
systems.
As for the choice of alternators,
that’s up to you and your needs. For backup, many builders are
using the small, 20 amp permanent magnet unit similar to those used on John
Deere garden tractors. B&C sells them with the appropriate
regulator. I chose to go with two of the 55A ND units. They are
used on many small cars and are very compact and can be converted to external
regulation fairly easy, should you choose to do it. They come with
different type of mounting tabs, so pay close attention to that aspect.
Another change I made to improve longevity
was to oversize the alternator pulleys, as well as undersize the eccentric
pulley. This reduced the maximum alternator rpm to about 10,000.
This is about half of what it was initially. By reducing the eccentric
pulley, it slows down the alternators as well as the water pump. I would
have to check my records to find the supplier for the oversized pulleys.
It may have been Canton Racing, but I’m not certain.
Mark S.
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of wrjjrs@aol.com
Sent: Tuesday, January 24, 2006
12:57 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Two
Alternators?
I would be very interested as I'm running a 20B in my
RV-10. Can you send me details?
-----Original Message-----
From: Mark R Steitle
<mark.steitle@austin.utexas.edu>
To: Rotary motors in aircraft
<flyrotary@lancaironline.net>
Sent: Tue, 24 Jan 2006 07:20:36 -0600
Subject: [FlyRotary] Re: Two Alternators?
I have dual alternators and dual batteries
per Aero-Electric Z-14
architecture. I?m using the small 55amp ND units. They weigh about
half of what the Mazda alternator weighs, so I rationalized that there was very
little weight penalty to using two alternators, but a significant safety
improvement. With an electrically dependent engine and all electric
panel, I decided this was the way to go for me. The cross-feed contactor
connects both Odyssey batteries during starting, so I am able to use smaller batteries
than would be required to start the 3-rotor with only one battery. Every
annual, I plan on replacing the main battery, rotating the 1 year old main
battery to the aux position, and move the 2 year old aux battery to my Goldwing motorcycle. That way
the main battery will be less than one year old, the aux battery will be 1 - 2
years old, and the motorcycle battery will be 2-3 years old. I?ll send
you a picture off-line.
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On Behalf
Of DLOMHEIM@aol.com
Sent: Tuesday, January 24, 2006
6:11 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Two
Alternators?
I am debating the future use of two
batteries vs. two alternators and
I was wondering if anyone in the group has mounted a second alternator and if
so if they had any pictures of its mounting location, etc.
Thanks for the information.
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