Today's Message Index:
----------------------
1. 12:46 AM - Key start switch/magneto problem ()
2. 05:52 AM - Re: interesting failure(s) (Robert L. Nuckolls, III)
3. 04:50 PM - ACE9011 (Sam Marlow)
4. 06:29 PM - Re: Key start switch/magneto problem (Robert L. Nuckolls, III)
5. 06:59 PM - Re: Key start switch/magneto problem (Charlie England)
Message 1
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| Subject: | Key start switch/magneto problem |
I have an intermittent problem with which I could use some help.
I have a left/right/both/ start switch activated by a key. On the left circuit
is a Lightspeed electronic ignition and on the right circuit is a traditional
magneto.
I went to fly the other day, and after start up, I had no RPM information on the
Grand Rapids engine instruments display. I tried a run-up test, and when going
from "both" to "right", the engine stopped running, but would come back to
life when either "both" or "left" was selected.
The next day I tried it again and everything worked normally?
Any advice on where to begin troubleshooting? Keyed mag/starter switch? Magneto?
Thanks in advance for any advice!
Message 2
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| Subject: | Re: interesting failure(s) |
At 10:23 PM 4/16/2007 -0700, you wrote:
>
>At 20:52 4/16/2007, you wrote:
>><nuckollsr@cox.net>
>> I dug through some F33 and A36 drawings today and as far
>> as I had time to research today, the first diodes to go
>> onto the battery master contactor was a pair of 1N4007,
>> 1A devices from EACH fat terminal to the (+) side of the
>> coil terminal this permitted a battery contactor to close
>> using power from either a good battery or a bus powered from
>> ground power.
>>Our ground power jacks drove the bus
>> side of the battery contactor . . . so the diodes made
>> sure that you could get the contactor closed from
>> ground power if the battery were dead. See . . .
>>
>>http://www.aeroelectric.com/temp/Early_Battery_Master.jpg
>
> From the early jpg you posted, and it's a bit difficult to clearly see,
> it appears CR24 has it's anode connected to the coil of K15 and the
> cathode to the battery and fat terminal of K15. If this is correct, this
> diode would be reverse biased by the battery and could not provide any
> current to the relay coil, but rather a discharge path for the collapsing
> field of the relay when de-energized. Diode CR25 OTOH, with it's cathode
> connected to the coil, would provide a current path for energizing power
> to the relay, assuming a voltage was present on bus M24 or M25(?). So,
> as drawn, K15 would only be energized with power on the M bus and with
> S29 closed.
>
>Is this an error in the schematic or just an artifact of the scan?
Crummy proportionality in our schematics of that era.
I've cleaned it up a bit.
>> Some years later, a 1.5KE51CA (bi-directional, 51v TVS)
>> was added across the coil of the battery contactor. See . . .
>>
>>http://www.aeroelectric.com/temp/Later_Battery_Master.jpg
>
>On the later jpg, both CR24 and CR25 appear to have their cathodes
>connected to the high coil terminal. With S29 closed and energizing
>voltage present at either the M bus or battery the coil and relay, as you
>state, could be energized. This seems like the correct configuration.
Yeah. I've cleaned that one up a bit too . . .
Message 3
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Is this unit, (ACE9011), suitable for use on an internal regulated
alternator, and if not, what should I do to reduce my vulnerably to over
voltage on a Van's 60 amp alt?
Thanks,
Sam Marlow
Message 4
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| Subject: | Re: Key start switch/magneto problem |
At 03:42 AM 4/17/2007 -0400, you wrote:
>
>I have an intermittent problem with which I could use some help.
>
>I have a left/right/both/ start switch activated by a key. On the left
>circuit is a Lightspeed electronic ignition and on the right circuit is a
>traditional magneto.
>
>I went to fly the other day, and after start up, I had no RPM information
>on the Grand Rapids engine instruments display. I tried a run-up test,
>and when going from "both" to "right", the engine stopped running, but
>would come back to life when either "both" or "left" was selected.
>
>
>The next day I tried it again and everything worked normally?
>
>Any advice on where to begin troubleshooting? Keyed mag/starter
>switch? Magneto?
>
>Thanks in advance for any advice!
Don't know what advice to give. The transient event
is essentially impossible to troubleshoot when it
won't hold still long enough to diagnosed. Which
system drives the RPM display. Which system is designated
the "right" system. If the right system is the source
for tachometer info, then the symptoms you cite point
to a transient failure of that system. Until it
happens again and stays broke, the best you can
do is wiggle all the joints and see if you can find
anything loose.
Bob . . .
----------------------------------------
( IF one aspires to be "world class", )
( what ever you do must be exercised )
( EVERY day . . . )
( R. L. Nuckolls III )
----------------------------------------
Message 5
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| Subject: | Re: Key start switch/magneto problem |
psiegel@fuse.net wrote:
>
> I have an intermittent problem with which I could use some help.
>
> I have a left/right/both/ start switch activated by a key. On the left circuit
is a Lightspeed electronic ignition and on the right circuit is a traditional
magneto.
>
> I went to fly the other day, and after start up, I had no RPM information on
the Grand Rapids engine instruments display. I tried a run-up test, and when
going from "both" to "right", the engine stopped running, but would come back
to life when either "both" or "left" was selected.
>
>
> The next day I tried it again and everything worked normally?
>
> Any advice on where to begin troubleshooting? Keyed mag/starter switch? Magneto?
>
> Thanks in advance for any advice!
Does the mag p-lead drive the GR tach? If so, it sounds like the mag's
p-lead is still grounded even when you select it with the switch.
I'd lift the p-lead from the switch & see if it will run on the mag. If
not, then I'd break the connection between the p-lead & the GR tach.
(might be a problem in the tach keeping the p-lead grounded)
Oops, just read the line about it being back to normal. Intermittent
sounds a lot like the switch, if you don't have any wires chafing
against the airframe anywhere.
Charlie
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