> Bob -
> >Here are more specifics for this installation:
> >
> >The wiring diagram provided by the builder (and it seems to be accurate)
> >is the "Z-1, Simple system with Toggle Mag Sw and Linear Regulator."
Okay, this drawing was 'retired' at Z-9 or so and replaced
with Z-11. They are similar in many respects.
> >The battery is a Concorde RG 25XC.
> >The alternator is a B+C L40, s/n 010806.
> >The regulator/OV prot is a B+C LR-3, s/n 11920211.
I don't recall how to read B&C's serial numbers
with respect to manufacturing date. But it may
well be that this one pre-dates the modifications
added later to reduce probability of nuisance
trips.
> >
> >The C/B from the alt output is only 40 amps! I'm guessing it should be
> >bigger based on your previous comments or I can use a current limiter you
> >suggest but I'll need to know which one/where are they available.
You can get the legacy current limiters and mounting
bases from B&C. Alternatively, a MAXI fuse holder from
the O'Rileys or some other parts store would do too.
http://aeroelectric.com/Pictures/Fuses/Fuse_Holders/MaxiFuse_Holder.jpg
http://aeroelectric.com/Pictures/Fuses/Fuses/maxi.gif
They can supply the fuse too. Use a 60A. Tie the
fuseholder onto the fat wire that feeds your starter
contactor and tie b-lead power into the system at
the starter contactor.
> > The alternator field fuse that has blown several times I rechecked and
> > is 15 amps. Does the "nuisance trip" scenario you speak of manifest as
> > blowing the 15 amp fuse?
Yes. I dug back into the archives and found that
Z-1 suggested the 15A fuse protected feeder from
the fuseblock that was followed downstream by a
5A breaker on the panel. Later drawings suggested
a much more robust protection of the alternator field
breaker feed in the form of a fusible link . . . see
Z-11.
For your purposes now, replace the 15A fuse with
a 30A fuse. This will probably transfer the trip to
the breaker instead of the fuse. It seems likely that
the LR3 is seeing something that irritates it's ov
protection sensing.
The original design observed all the recommendations
for noise immunity but when we started installing this
system in the Bonanzas, one of the test pilots found that
if he turned both landing and taxi lights on at the same
time, he could trip the standby alternator ov system.
The noises generated by this event were pretty spectacular.
Inrush currents from two large lamps through the very bouncy
contacts of W31 breaker-switches put some really ugly
transients onto the bus. It was doubtful that anyone would
DO that thing but it wasn't difficult to modify the
circuit to ignore this stimulus. We modified the circuit
and have experienced no difficulties (that I'm aware of)
since.
> >What else would you like to know and what do you think? Thank you. JBB
Call B&C at 316-283-8000 and see if they're interested
in updating your LR-3 with respect to noise immunity.
If push comes to shove, I can modify it for you but
let's see what they say first.
Bob . . .
Bob -
Talked to Bill at B+C this afternoon and he wasn't too convinced the LR-3B needed
much of an upgrade. He says there is a LR-3C being built now and I get the
idea it has some transient type improvements built in. His suggestion was to
monitor the low voltage light to see under which conditions it comes on. I don't
think I can get it to trip when I want. I am suspecting it might not be
a consistent cause i.e. the dreaded intermittent type of thing. But, I now know
enough about the location of components in my particular system to troubleshoot
if I knew where to start. The only thing I have done is put a 20 amp fuse
in the field location. I haven't flown it yet this way. JBB
