Return-Path: Received: from fed1rmmtao07.cox.net ([68.230.241.32] verified) by logan.com (CommuniGate Pro SMTP 4.2.4) with ESMTP id 455230 for flyrotary@lancaironline.net; Wed, 06 Oct 2004 15:52:35 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.32; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao07.cox.net (InterMail vM.6.01.03.04 201-2131-111-106-20040729) with ESMTP id <20041006195203.GMMV8184.fed1rmmtao07.cox.net@BigAl> for ; Wed, 6 Oct 2004 15:52:03 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: #$!%@$ temperatures still high Date: Wed, 6 Oct 2004 12:52:07 -0700 Message-ID: <000001c4abdd$f61cef30$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C4ABA3.49BE1730" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C4ABA3.49BE1730 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 Then it hit me - The alternator is using an OV protected 5Amp circuit = from the same board. and the lights really seem to sort of flicker (have = tried about 10 different useless solutions for that one). =20 Anyway, the excitation current for the alternator must be right at about = 5 amps. Turns out the micro relay has been tripping, then resetting = itself 2-3 times /sec. Turning the alternator on and off with it. The poor = voltage regulator must have been working overtime as my buss voltage read a = steady 14.2V. The fluctuations were too fast to register on the voltmeter. = The voltage must have been going from battery voltage up to about 16+ volts = to maintain the average of 14V read by the meter. As you can guess, electronics don't like that kind of thing - but most things worked surprisingly well. =20 I bypassed the stupid circuit board and connected the alternator field directly to the alt output. Wow what a difference. The EC2 and fuel = pumps were probably the most affected. All of a sudden I can get idle out of = the ultra rich and put the mixture right. Idle is MUCH better. I even had = to reset the idle stop so I could idle lower. Down to 1000 RPM or less now = and it sounds great. Oh, the lights stopped flickering and the radios sound better too. Go figure. =20 Dave Leonard =20 Dave; =20 That's interesting. Makes me wonder whether I should put a scope on = voltage and see if it is smooth. =20 =20 The downside of connecting the field to the output, as I'm sure you = know, is that you now have the risk of a runaway voltage condition if the VR = fails. I guess the odds are low, but the costs could be high. Avionics? =20 I assume that you have a breaker (or fuse) in the alt field circuit. = You can put a "crowbar" circuit between the field lead and ground that will = trip the breaker in an over-voltage condition. I got one from Aeroelectric. =20 Al =20 ------=_NextPart_000_0001_01C4ABA3.49BE1730 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

Then it hit me - The alternator is using an OV protected 5Amp circuit = from

the same board… and the lights really seem to sort of flicker (have = tried

about 10 different useless solutions for that one).

 

Anyway, the excitation current for the alternator must be right at about = 5

amps.  Turns out the micro relay has been tripping, then resetting = itself

2-3 times /sec. Turning the alternator on and off with it.  The poor = voltage

regulator must have been working overtime as my buss voltage read a = steady

14.2V.  The fluctuations were too fast to register on the voltmeter.  = The

voltage must have been going from battery voltage up to about 16+ volts = to

maintain the average of 14V read by the meter.  As you can = guess,

electronics don’t like that kind of thing – but most things = worked

surprisingly well.

 

I bypassed the stupid circuit board and connected the alternator = field

directly to the alt output.  Wow what a difference.  The EC2 and fuel = pumps

were probably the most affected.  All of a sudden I can get idle out of = the

ultra rich and put the mixture right.  Idle is MUCH better.  I even = had to

reset the idle stop so I could idle lower.  Down to 1000 RPM or less now = and

it sounds great.  Oh, the lights stopped flickering and the radios = sound

better too.  Go figure.

 

Dave Leonard

 

Dave;

 

That’s interesting.  = Makes me wonder whether I should put a scope on voltage and see if it is = smooth. 

 

The downside of connecting the = field to the output, as I’m sure you know, is that you now have the risk of = a runaway voltage condition if the VR fails.  I guess the odds are = low, but the costs could be high. Avionics?

 

I assume that you have a breaker = (or fuse) in the alt field circuit.  You can put a “crowbar” = circuit between the field lead and ground that will trip the breaker in an = over-voltage condition.  I got one from Aeroelectric.

 

Al

 

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