Ronald,
My guess is that the engine is not running
at high enough rpms during taxi to provide the needed amps so the battery is
being slowly drained during the taxi. Then when you do the run up, the AC
is being supplied as well as the battery is being replenished. This requires
the 85 amps then dropping to 70 as the battery comes back up. In flight,
everything requires 44 amps except when the compressor kicks on which pulls a
spike up to 60 for a moment or so.
The breaker is popping because the AC is
pulling more amps than the breaker is set for. I could not guess at why
that is the case. What is this breaker protecting? The fan? The
compressor clutch? Everything else is mechanical off the engine…??
Bill B
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of RONALD STEVENS
Sent: Wednesday, August 03, 2011
11:11 AM
To: lml@lancaironline.net
Subject: [LML] This is puzzling
..and not only me...
This is puzzling me
and some others that I asked as well. Here is the thing.
When I switch on my AC
and it starts kicking in my amps goes up until 60 amps and than usually settles
around 43 amps. Which is fine I have a 100 amp alternator. Then I start my taxi
and the amps pretty much stays the same (with AC on).
But when I am doing a
run-up my amps goes all the way to 85amps…hovers there a little and then
settles back to around 70amp @ 1700rpm
In flight when the AC
is running (cruise) my amps are around 44amps. Sometimes it goes to 60amps,
this is when the AC kicks in again.
The puzzling part is,
why it goes all the way to 85amps and than goes back again on the run up? I
hope to trigger some Ideas here.
I am having problems
that my breaker from the AC pops after about 15-20min after start.