AeroElectric-List Digest Archive

Tue 04/24/07


Total Messages Posted: 9



Today's Message Index:
----------------------
 
     1. 03:21 AM - GNS 430W Antenna Requirements ()
     2. 05:45 AM - Re: PM ALTERNATOR- REGULATOR CHOICE (Ken)
     3. 06:39 AM - Re: GNS 430W Antenna Requirements (Wayne Sweet)
     4. 07:59 AM - Re: Relay and capacitor info needed (Robert L. Nuckolls, III)
     5. 01:59 PM - Re: PM ALTERNATOR SPIKE PROTECTION (NOT) (James Foerster)
     6. 05:25 PM - Re: Re: DIY Intercom System (Robert L. Nuckolls, III)
     7. 07:24 PM - Easy question? (RV Builder (Michael Sausen))
     8. 08:22 PM - Re: Easy question? (Ernest Christley)
     9. 09:31 PM - Re: DIY Intercom System (az_gila)
 
 
 


Message 1


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    Time: 03:21:24 AM PST US
    From: <bakerocb@cox.net>
    Subject: GNS 430W Antenna Requirements
    4/24/2007 Hello Wayne, Thanks for your input. One more question if I may. I have read that the connector on the end of the coax cable that connects to the antenna must be a male TNC connector. Can you please confirm that? Also I'd appreciate it if you can shed any light on what additional equipment, antenna, black box, or...........? would be needed if one wanted to have XM weather appear on their GNS 430W. Thanks. OC -- The best investment we can make is the effort to gather and understand knowledge. Time: 08:59:22 PM PST US From: "Wayne Sweet" <w_sweet@comcast.net> Subject: Re: Avionics-List: GNS 430W Antenna Requirements I have my GNS430W installed with the antenna mounted on the aft of the canopy (BUSHBY MustangII); the RG400 coax is about 8 feet in length. No noticeable difference from the same location prior to the WAAS update. BTW, I'm having a ball flying GPS approached with ILS like display. In fact the needles are much calmer than on a ILS approach, and no worry about false lobes. :-))) Only problem (small), from the approach plate can't tell if there will be an active GS till I get on the approach and get the LNAV+V indication. The GS comes active on the waypoint just outside the FAF. Wayne


    Message 2


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    Time: 05:45:23 AM PST US
    From: Ken <klehman@albedo.net>
    Subject: Re: PM ALTERNATOR- REGULATOR CHOICE
    To his credit, Peter has been asking lots of questions and I was trying to understand whether it was worth his effort to change parts and insure self excitation. For my Z-14 system, it doesn't matter to me whether either alternator will self excite. If I don't like how the engine is running, my procedure is to just switch to the second EFI system, which runs on the other battery and alternator. Self excitation is fine but I would encourage a bit of testing before counting on continued operation without a battery. Especially with a regulator that was not designed to perform without a battery. Now that Peter's has described what he is trying to do, I agree that self excitation or a second battery is essential for him. However self excitation might not help much if someone inadvertantly stalled the alternator and had a geared prop that promptly stopped turning. Self excitation might not be as comforting if Peter's EFI Jabiru doesn't windmill fast enough to restart his engine. For example he might want to insure that with his system it is not possible to inadvertantly (out of habit) turn on something like a landing light and stall the alternator... His "dual" power source should probably be strictly for feeding the engine. My PM alternator doesn't put out much current at idle rpm. Ken Robert L. Nuckolls, III wrote: > <nuckollsr@cox.net> > > At 08:52 AM 4/23/2007 -0400, you wrote: > >> >> Peter >> >> I'm not sure why you want a regulator that will start up without a >> battery? It sounds like you do have a battery present. Do you know >> for sure that your regulator will not start without a battery present? > > > Why would one NOT want an alternator that will run > without a battery. Generators did this from day-one > and we had to give that feature up when generators got > replaced by alternators in the 60's. > > Alternators on the Bonanza and Barons have self excited > for decades and the company touts this as a desirable > feature. A few months ago we did an exercise to figure > out how to make an SD-8 come up without assistance from > a battery. > > This is generally considered a good thing to do and it > can be done. > > Bob . . .


    Message 3


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    Time: 06:39:35 AM PST US
    From: "Wayne Sweet" <w_sweet@comcast.net>
    Subject: Re: GNS 430W Antenna Requirements
    Yes, it does need a TNC connector at the antenna; the dealer that sent mine in to Garmin for the WAAS upgrade made a pigtail TNC to BNC for me ( $10.00 :-))) ) . Don't know about what additional boxes needed for XM. Wayne ----- Original Message ----- From: <bakerocb@cox.net> Cc: <aeroelectric-list@matronics.com> Sent: Tuesday, April 24, 2007 3:19 AM Subject: GNS 430W Antenna Requirements > 4/24/2007 > > Hello Wayne, Thanks for your input. One more question if I may. > > I have read that the connector on the end of the coax cable that connects > to the antenna must be a male TNC connector. Can you please confirm that? > > Also I'd appreciate it if you can shed any light on what additional > equipment, antenna, black box, or...........? would be needed if one > wanted to have XM weather appear on their GNS 430W. > > Thanks. > > OC -- The best investment we can make is the effort to gather and > understand knowledge. > > Time: 08:59:22 PM PST US > From: "Wayne Sweet" <w_sweet@comcast.net> > Subject: Re: Avionics-List: GNS 430W Antenna Requirements > > > I have my GNS430W installed with the antenna mounted on the aft of the > canopy (BUSHBY MustangII); the RG400 coax is about 8 feet in length. No > noticeable difference from the same location prior to the WAAS update. > BTW, I'm having a ball flying GPS approached with ILS like display. In > fact > the needles are much calmer than on a ILS approach, and no worry about > false > lobes. :-))) Only problem (small), from the approach plate can't tell > if > there will be an active GS till I get on the approach and get the LNAV+V > indication. The GS comes active on the waypoint just outside the FAF. > Wayne >


    Message 4


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    Time: 07:59:50 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: Relay and capacitor info needed
    At 05:27 PM 4/23/2007 +0000, you wrote: > >Hello Bob > >I think my questions may have gotten lost during your sojourne: >**** The yellow output wire of the Rotax generator is AC. My question has >to do with the internal pressure of the relay blowing apart the sealed >container like a bag of potato chips that will explode at altitude. Do you >think this relay can take the internal pressure of 35K or 18K at 212F >without exploding? There are two major issues with environmental pressure reduction. Cooling for devices that depend on moving air to shed heat. It's amazing how hot things can get with -50C air blowing over it a 200Kts IAS when that air is ambient at 41K feet! The other is increasing difficulty for preventing arcing. This can be a concern for ordinary spacing issues with non-moving parts carrying high voltage. It's a special concern with breaking a circuit with a switch or relay that carries a DC inductive load. This is why magnetos get pressurized on some airplanes. There are NO concerns for mechanical failure (blowing apart) due to increasing altitude. > > > > Why not wire your PM alternator like Z-16 and leave the capacitor > > across the battery all the time? > >**** If running on E-Bus, having a leaking capacitor that can not be >disconnected will defeat much which I desire in my design. I am not using >a Battery contactor, but a Flaming River switch, and turning it off will >not sever the capacitor from the E-Bus. I am willing to accept the extra >complexity to have this extra relay that will disconnect the capacitor >when Rotax generator is turned off either by generator switch or OV. This >is in addition to opening the AC with S704-1 relay. Yes kinda like wearing >suspenders and a belt, but it will accomplish what I desire. You're worrying too much. The capacitor is not a big hazard item. It's going to go open (capacity reduces) as it ages. Put a new one in every so often if you're worried about it but adding a special disconnect capability has no return on the expenditure . . . i.e. poor investment. >My question is do you think this vented 75 amp relay will provide >reasonable service living on the engine side of the firewall with regard >to condensation causing problems (corrosion/contamination ingress) and or >any other problems that can be associated with a vented relay? Define "reasonable". We have no mechanism by which MTBF can be accurately calculated and compared with your sense of "reasonable" . . . this is why I preach the doctrine of failure tolerant design. Best way to have a part become a maintenance issue is not to leave it off. You don't need to have panel control over whether or not the capacitor is connected. > > > > If you're wired per the latest control philosophies for PM > > alternators, the capacitor charges through the battery contactor > > which won't be particularly stressed by this activity. The > > act of charging the capacitor using the output of the alternator > > is current limited by the alternator's dynamics. No inrush > > concerns here. > >**** I am not precise following the latest control philosophies for PM >alternators. I addressed concerns in my design to allow operations from >total loss battery/s for extended soaring, failure of main battery if it >occurred during an inflight restart after soaring, once motor running on a >failed main battery I can get Rotax generator on line to power E-Bus, if >smoke from electric, I can shut down everything and have a fuel pump >running autonomous in seconds. > >I want to use either a 75 amp Bosh Relay or a B+C S704-1 to disconnect DC >side from Generator. Do you think the 75 amp relay will hold up charging >the 22K uF capacitor at least once per flight? Do you think a B+C S704-1 >relay will hold up charging the 22K uF capacitor at least once per flight? >Again this relay will be the tool used to make a connection and charge the >capacitor. What you want to do will function. I have no foundation in physics or experience to put lower limits on service life. I have no concerns for extraordinary stress that might be expected to impact the ordinarily good service for these components . . . but if it were my airplane, I wouldn't even install it. > > > > What kind of trim motors? You're probably fine with MAC/RayAllen > > actuators. You could easily go all solid state with these duties > > and eliminate the worries entirely. You're not going to "blow them > > apart" . . . the risk is that at reduced pressures, the arcing > > that inevitably forms between spreading contacts is more severe > > and you get reduced service life. I've not tested open relays at > > these altitudes . . . our mil-spec products are sealed. > >**** It is a Ray Allen, I forget the exact model but it is the smallest >one with a indicator. Question is again about blowing them apart because >the internal pressure is higher than the outside pressure at altitude. I >doubt design had in mind aircraft use??? Do you think there is a good >chance that they will not blow apart? Please ditch this concern about blowing anything up. Electro-whizzies for aircraft are not selected for their ability to resist any tendencies to spontaneously disassemble due to effects of altitude. Any of the hardware installed to support the R-A actuators at pedestrian altitudes will be fine in you airplane. Bob . . .


    Message 5


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    Time: 01:59:01 PM PST US
    From: "James Foerster" <jmfpublic@comcast.net>
    Subject: RE: PM ALTERNATOR SPIKE PROTECTION (NOT)
    Bob, Regarding the PM alternators, you wrote: A few months ago we studied and solved the problem of getting the SD-8 to come up self-excited. This is where the resistors and rectifier were added to Z-25. At some later time and under a different discussion topic, we considered moving the control relay to the AC side of the PM alternator's regulator as shown on the current revision of Z-16. However, this is a case of not having your cake and eating it too. Moving the control relay to the AC side of the regulator kills our ability to come alive self excited. We'll have to throw the pot back on the stove to see if we can achieve both qualities from a single architecture. Here is a possible entry for the pot. Design so that the relay and the S1 controlling switch get power either from the battery or the same bridge circuit of Z25. A diode would be placed in series from the main battery bus to the fuselink, and the output from the diode bridge would also be fed by a series diode to the upstream (bus) side of the circuit breaker. Diodes would need to be in the 100 to 200 volts range, but that is not difficult. If smaller breakers than 5 amps are available that would be better, too. A more elegant solution would use a thyristor triggered by a pulse from the overvoltage module, but I haven't tried to draw that one. This is looking like a job for a small printed circuit board again. Jim Foerster, J400 slowly wiring


    Message 6


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    Time: 05:25:04 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: DIY Intercom System
    At 10:33 PM 4/20/2007 -0700, you wrote: > >I'd like to see a easy (cheap) audio mixer for use with a commercial intercom. >Simple panels probably only have 3 or 4 audio sources (including alerts) >and a full audio panel is way overkill. Most folks don't even use the >speaker any more, so phones only are OK. > >I was thinking of a simple audio mixer and a Tx1/Tx2 switch.. perhaps from >a ready made kit... such as this one... > >http://store.qkits.com/moreinfo.cfm/FK652 > >Would like to hear other suggestions.... See: http://www.aeroelectric.com/DIY/Audio_Isolation_Amplifier.pdf Bob . . .


    Message 7


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    Time: 07:24:17 PM PST US
    From: "RV Builder (Michael Sausen)" <rvbuilder@sausen.net>
    Subject: Easy question?
    I have a device that lives quite happily between around 11vdc to around 13.9vdc and then promptly stops working above that number. Problem is most charging systems are above 14vdc. It uses milliamps at best so I'm looking for the easiest way to drop a volt. Michael Sausen RV-10 #352 Limbo Do not archive


    Message 8


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    Time: 08:22:42 PM PST US
    From: Ernest Christley <echristley@nc.rr.com>
    Subject: Re: Easy question?
    RV Builder (Michael Sausen) wrote: > > I have a device that lives quite happily between around 11vdc to around 13.9vdc and then promptly stops working above that number. Problem is most charging systems are above 14vdc. It uses milliamps at best so I'm looking for the easiest way to drop a volt. > > > A couple of diodes in series will give you between 1 and 1.5 volt drop.


    Message 9


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    Time: 09:31:59 PM PST US
    Subject: Re: DIY Intercom System
    From: "az_gila" <gilalex@earthlink.net>
    Bob... if I wanted to switch sources on and off, would a switched short to ground between the input resistor and capacitor for a single input work? Such as shorting the junction of R104 and C112 to ground (page 1.8.1 schematic) gil A Read this topic online here: http://forums.matronics.com/viewtopic.php?p=109110#109110




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