Today's Message Index:
----------------------
1. 03:12 PM - Re: Over-voltage relay (Yak Pilot)
2. 03:29 PM - Re: Re: Over-voltage relay (Yak Pilot)
3. 03:43 PM - Engine won't air start (jetfighterrides)
4. 03:56 PM - Re: Engine won't air start (ronald wasson)
5. 08:06 PM - Re: Engine won't air start (A. Dennis Savarese)
Message 1
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| Subject: | Re: Over-voltage relay |
There are many designs, and many ways to approach your goal.---
-
You might consider "borrowing" the exact system B&C has set up for their sm
all PMG altenator.- You can just order their over-voltage kit for for the
ir 10 amp PMG unit.- This thing is a simple crow-bar circuit that when th
e voltage goes over about 30.5 VDC causes a circuit breaker to blow.- Thi
s circuit breaker powers a relay.- The relay opens, and disconnects gener
ator output.-
-
It would be very very simple to take this exact circuit and apply it to any
alternator or generator out there.- If you need help changing the design
to meet your exact needs, feel free to contact me off-line.-
-
Mark Bitterlich
--- On Thu, 12/3/09, Kelley Monroe <kelmonroe@comcast.net> wrote:
From: Kelley Monroe <kelmonroe@comcast.net>
Subject: Yak-List: Over-voltage relay
I have a CJ with a Delco 24V, 40A, alternator with-integral voltage regul
ator on it.- The system doesn't have any over voltage protection.- Does
anyone have an idea of what relay-I should install?- Thanks Kelley
Message 2
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| Subject: | Re: Over-voltage relay |
Which Cessna?- Which Piper?-- Their systems all vary.- In some Cess
na's there is no disconnect, only an over-voltage warning light, with a mod
ule connected underneath the front panel.- They rely on the voltage regul
ator completely, and if it goes bad, then the over-voltage light comes on a
nd you turn the system off manually.- This approach does indeed have adva
ntages because the pilots brain is engaged as what the exact course of acti
on should be.- This assumes that the pilot knows the electrical system, w
hat will happen if the light is ignored, and when it might be a good idea t
o simply ignore the light for a few minutes and leave the alternator turned
on.- On the other hand, you step up to a big twin like a Cessna 421 and
they take a much more sophisticated approach to electrical management and e
lectrical failures.-
-
What it boils down to really is what approach you want to take, and this in
turn is usually determined by what you are doing with the airplane and how
much money you want to spend.-
-
The person who posed the original question is flying an experimental airpla
ne with a electrical system that differs from the original design.- He ex
pressed a desire for an over-voltage protection system.- Indeed, one coul
d take the over-voltage module out of a Cessna 180 and connect it to this a
lternator and make it work exactly the same.- Nothing but a warning light
.-
-
Or, a person could design their own system and make it do anything they wan
ted it to do!- I tend to favor that approach, but my field is Avionics to
begin with, so it is obvious why I would want to design my own system to d
o exactly what I want.---
-
Indeed, I have wired in an over-ride circuit into the stock YAK-50 design s
o that I can manually control the main contactor relay.- Used incorrectly
, I could blow fuses everywhere, but used correctly, it allows me to manual
ly control the whole system and get me to my destination in an extreme situ
ation.- (No one flies this aircraft but me!).-
-
Given the inherent danger of an over-voltage condition,- I would want a s
ystem that:
-
1.- Disconnects the source of the over-voltage automatically, with manual
over-ride as necessary.
2.- Lets me know about it with a warning light.-
3.- Is easy to fix and find parts for.-
-
The complete B&C replacement system does ALL of that.-
-
The B&C over-voltage crowbar circuit (alone) -can be adapted to work and
do all of that as well with a custom designed alternator package such as th
e gent in question appears to be using.-
-
Or you can just start from scratch and design your own, which is not all th
at hard to do.-
-
Best Regards,
-
Mark Bitterlich
-
--- On Thu, 12/3/09, jblake207@comcast.net <jblake207@comcast.net> wrote:
From: jblake207@comcast.net <jblake207@comcast.net>
Subject: Re: Yak-List: Re: Over-voltage relay
#yiv1616440324 p {margin:0;}
Why would this system-be any different than an over volt system on Cessna
s, Mooneys, Pipers, etc?
----- Original Message -----
From: "Craig Winkelmann" <capav8r@gmail.com>
Sent: Thursday, December 3, 2009 2:05:00 PM GMT -06:00 Central America
Subject: Yak-List: Re: Over-voltage relay
It is not that simple......I am sure if you look in the list archive, you w
ill find Mark Bitterlich has done some very nice posts on the value of and
design of a crowbar overvoltage protection circuit. -Basically, you need
a circuit that detects the overvoltage at a certain setpoint and opens the
field to the alternator and keeps it open. -No field voltage, no voltage
out of the alternator.
Here is a useful link:
http://www.gatm.com/flying/electrical/phase_iv.html
Another option is to scrap the system you have and install a B&C system (sy
stem means, alternator, voltage regulator/protection, proper pinion gear, p
roper mounting plate for the alternator) that provides all the protection y
ou may want or need. -As you read in the above link, B&C has incorporated
many safety features in their design. -They also include a shear coupler
between the engine drive gear and the alternator. -In the case of an alt
ernator bearing failure, the shear coupler fails instead of the pinion gear
inside your engine.
Happy flying,
Craig W.
Craig W
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=276017#276017
Message 3
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| Subject: | Engine won't air start |
Our Yak-52(year:1985), still fails to kick over(start) once the air start button
is pushed. We simply get a hissing from the starter solenoid valve region, and
the prop vibrates, and shutters a little. As a result we have been prop starting
(hand swinging) the yak. We have conducted the following maintenance in
order to rectify the issue:
1) New Vibrator Box;
2) Changed the starter-solenoid;
3) Listened to the starter air distributor spider, for any obvious air leaks;
4) Listened to the lines to and from the spider, for any obvious air leaks;
5) Sprayed WD-40 in the starter solenoid valve, and exercised it;
6) Both the start Voltage and Amps were sufficient;
7) Activated the starter solenoid override valve switch on the inboard
firewall;
8) Reset the prop to TDC after an attempted start, then reattempted a start;
9) All starts are conducted with system pressure greater than 50kgf/cm;
We still have no joy, and we are running out of options. We are considering replacing
or overhauling the air distributor spider?
Any thoughts would be greatly appreciated.
--------
Regards
Matthew Doherty
Pilot/owner
www.jetfighterrides.com.au
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=276243#276243
Message 4
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| Subject: | Re: Engine won't air start |
Stuck valve maybe. Prop it thru once to get it off the bad cylinder. If the starter
works for 2 or 3 blades than stops that is a sign . It stops on the bad cylinder
and hisses out he exhaust with a hung valve. Getting the motor running
and warmed up with break the valve loose. Running the motor once a week will
stop it.
On Dec 4, 2009, at 5:41 PM, jetfighterrides wrote:
>
> Our Yak-52(year:1985), still fails to kick over(start) once the air start button
is pushed. We simply get a hissing from the starter solenoid valve region,
and the prop vibrates, and shutters a little. As a result we have been prop starting
(hand swinging) the yak. We have conducted the following maintenance in
order to rectify the issue:
>
> 1) New Vibrator Box;
> 2) Changed the starter-solenoid;
> 3) Listened to the starter air distributor spider, for any obvious air leaks;
> 4) Listened to the lines to and from the spider, for any obvious air leaks;
> 5) Sprayed WD-40 in the starter solenoid valve, and exercised it;
> 6) Both the start Voltage and Amps were sufficient;
> 7) Activated the starter solenoid override valve switch on the inboard
> firewall;
> 8) Reset the prop to TDC after an attempted start, then reattempted a start;
> 9) All starts are conducted with system pressure greater than 50kgf/cm;
>
> We still have no joy, and we are running out of options. We are considering replacing
or overhauling the air distributor spider?
>
> Any thoughts would be greatly appreciated.
>
> --------
> Regards
>
> Matthew Doherty
>
> Pilot/owner
>
> www.jetfighterrides.com.au
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=276243#276243
>
>
>
>
>
>
>
>
>
>
Message 5
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| Subject: | Re: Engine won't air start |
Did you check the hose from the firewall to the air start distributor?
I have seen these hoses split. The hissing sound sounds like it is
coming from the from the air start solenoid when in fact it is coming
right out of the fractured hose. If you remove the hose from the
firewall and press the air start button, you should have quite a bit of
pressure coming out of the firewall fitting. If you do have adequate
air pressure, I would suspect a damaged air start distributor which has
an internal spring which keeps pressure on the internal section.
Dennis
----- Original Message -----
From: ronald wasson
To: yak-list@matronics.com
Sent: Friday, December 04, 2009 5:53 PM
Subject: Re: Yak-List: Engine won't air start
<ronwasson@mindspring.com>
Stuck valve maybe. Prop it thru once to get it off the bad cylinder.
If the starter works for 2 or 3 blades than stops that is a sign . It
stops on the bad cylinder and hisses out he exhaust with a hung valve.
Getting the motor running and warmed up with break the valve loose.
Running the motor once a week will stop it.
On Dec 4, 2009, at 5:41 PM, jetfighterrides wrote:
<jetfighterrides@gmail.com>
>
> Our Yak-52(year:1985), still fails to kick over(start) once the air
start button is pushed. We simply get a hissing from the starter
solenoid valve region, and the prop vibrates, and shutters a little. As
a result we have been prop starting (hand swinging) the yak. We have
conducted the following maintenance in order to rectify the issue:
>
> 1) New Vibrator Box;
> 2) Changed the starter-solenoid;
> 3) Listened to the starter air distributor spider, for any obvious
air leaks;
> 4) Listened to the lines to and from the spider, for any obvious air
leaks;
> 5) Sprayed WD-40 in the starter solenoid valve, and exercised it;
> 6) Both the start Voltage and Amps were sufficient;
> 7) Activated the starter solenoid override valve switch on the
inboard
> firewall;
> 8) Reset the prop to TDC after an attempted start, then reattempted
a start;
> 9) All starts are conducted with system pressure greater than
50kgf/cm=C2=B2;
>
> We still have no joy, and we are running out of options. We are
considering replacing or overhauling the air distributor spider?
>
> Any thoughts would be greatly appreciated.
>
> --------
> Regards
>
> Matthew Doherty
>
> Pilot/owner
>
> www.jetfighterrides.com.au
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=276243#276243
>
>
>
>
>
>
>
>
>
>
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