----- Original Message -----
Sent: Saturday, January 16, 2010 9:58
AM
Subject: [FlyRotary] Re: Alternator
Filter
Hey Joe, if the capacitor
becomes resistive and they can, you will have a dc connection to
ground.
Measure the filter
(if you haven't already) to ensure it is 100% open-circuit.
Jeff
From: Rotary motors in aircraft
[flyrotary@lancaironline.net] On Behalf Of Joe Ewen
[jewen@comporium.net]
Sent: Friday, January 15, 2010 6:12
PM
To: Rotary motors in aircraft
Subject: [FlyRotary]
Alternator Filter
I have been having problems with my engine
installation. Starts, runs great - turn on the alternator and the engine
starts to miss. Put a scope on R1 ignition trigger lead and sure enough
missing trigger pulses. Turn alternator off no more missing
pulses. Looked at the alternator output with the scope and as expected
saw some spikes. Bought an aircraft spruce alternator filter. Ran
the engine , worked fine until it would not prime or run any more. That
turned out to be a defective store switch. Replaced the switch and back
to normal. Here is the part I do not yet understand.
Engine runs fine, added alternator filter and can
not even get a pop. Take the filter off, starts fine. Filter back
on (alt off), no joy. Filter on (alt on), no joy. Filter off, runs
fine. I can not imagine how a filter capacitor is interfering with the
ignition of the controller. If anyone has any insight please feel to
speak up.
I have 2 wiring ducts: 1. quiet - signals such as
to the PCM, ignition firing leads, low voltage sensor, analog signals.
2. Noisy side, battery cables, ignition power, injector power and signal
(twisted pair shielded (shield properly grounded.)
Alternator connects to battery cable at the
starter. If I run an external wire between the alternator and the
battery (outside the airframe, long wire - engine in back, battery in front
(canard)) everything runs fine.) Aesthetically this might not be a good
approach, not to mention the aerodynamic impact.
This problem has kicked my butt this week working
on it in the cool 20F evening air. Any insight is appreciated,
especially why a capacitor (which does not conduct DC) would render the EC2
controller inoperative would be appreciated.
Thanks,
Joe
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