europa-list
[Top] [All Lists]

Re: Europa-List: AC powered fin strobe

Subject: Re: Europa-List: AC powered fin strobe
From: Frans Veldman <frans@privatepilots.nl>
Date: Sat, 10 Dec 2011 15:21:57

On 12/10/2011 07:12 AM, Richard Lamprey wrote:

> The
> strobe power box is wired in series between the 912 generator wires
> (yellow) and the Ducati voltage rectifier.

Wait a minute. Is it really in series? If both yellow wires go to the 
Ducati AND both go to the strobe, it is parallel. If one yellow wire 
goes to the strobe, and one yellow wire to the ducati, and a new wire is 
used to connect the remaining ducati and strobe connectors together 
(like how X-mas tree lights are wired), it is indeed series.
It is quite important to know whether it is parallel or series, hence my 
question.

> Also, strangely, there is
> no circuit breaker or fuse in this system.

This would make sense if it is series indeed, otherwise you should use a 
fuse.

Anyway, I would advise for quite a number of reasons against a series 
diagram, but a parallel diagram would be ok. I would be surprised if it 
is series indeed, but you never know.

Assuming it is parallel, as it should be, I think it is a great 
solution. Strobes work on high voltages, so any strobe power supply 
needs to convert the low voltage DC into high voltage AC and then 
rectify it again. By feeding it directly from the alternator (where it 
is still AC) quite some losses can be avoided, and it also does not load 
the Ducati (which has a tendency to burn out easily). An AC-fed strobe 
can not be powered from the battery, but if the alternator fails the 
strobe is the first thing you should power down anyway, so this is no 
real disadvantage.
You should put a fuse between the alternator and strobe power unit. 
(Don't use a CB here, as you should never try to reset a tripped strobe 
CB during flight: it is not essential equipment and malfunctioning 
strobe power supplies are quite a hazard, so don't play with these 
things and just use a "one-time" fuse here to avoid any temptation!). I 
would put a switch in between too, as it is considered somewhat impolite 
to wait at the holding point with bright flashing strobes while there is 
someone on final, especially when it isn't very bright weather. I would 
also like to power down the strobe if I would smell any fuel during flight.

Frans



<Prev in Thread] Current Thread [Next in Thread>