Today's Message Index:
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1. 10:06 AM - Re: Battery Solenoid (Relay) (David J. Spencer)
2. 02:17 PM - Re: Battery Solenoid (Relay) (Martini Luc J.R.)
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| Subject: | Re: Battery Solenoid (Relay) |
--> Avionics-List message posted by: "David J. Spencer" <djs@54Transmission.com>
Luc...
There was approximately 11 ohms between the + & - with the correct polarity
hook up on the VOM.
I took out the battery cable yesterday and found a split in the insulation
about 3/8" long which had been taped over. The cable itself had been
"crimped" creating a bulge and part of the internal wiring was broken at
that point.
As best I could tell this open area was not laying on the skin but , rather,
pointing away from the skin as the cable lay on the belly of the plane.
This is being corrected with new wiring and proper attachments.
I hooked the radios up to a DC power source i.e. they are isolated from
anything (except the antenna)... and the hum went away.
David J. Spencer
Super3
djs@54Transmission.com
----- Original Message -----
From: "Martini Luc J.R." <martini@foxinternet.net>
Subject: Re: Avionics-List: Battery Solenoid (Relay)
> --> Avionics-List message posted by: "Martini Luc J.R."
<martini@foxinternet.net>
>
> What resistance do you read between the battery cable and ground. Be sure
> to take the measurement with the leads swapped as well as standard
polarity,
> i.e. red lead to + and black to -.. If you are NOT using a digital VOM,
> then also take values in both polarities in more than one RANGE on the VOM
> (active devices - diodes /transistors - are non-linear.. give you a good
> clue if the value changes). You may have another noise suppression diode
> somewhere, and/or an RC type (Band Pass) noise filter , with possibly a
bad
> capacitor in it.
>
> Let me know what you get.
>
> Luc Martini
> ----- Original Message -----
> From: "David J. Spencer" <djs@54Transmission.com>
> To: <avionics-list@matronics.com>
> Subject: Avionics-List: Battery Solenoid (Relay)
>
>
> > --> Avionics-List message posted by: "David J. Spencer"
> <djs@54Transmission.com>
> >
> > Hi all...
> >
> > Has anyone ever replaced the battery relay on their Beech A23-24 Super
> III?
> >
> > My relay seems to work fine, but is 36 y/o and uses a Kipvolt Voltage
> > suppressor (diode) to eliminate voltage spikes flushing through the
> system.
> >
> > I am replacing the battery, ground and starter cables with new cable
(AC
> > grade #0 wire for the 40 amp system) and am wondering if anyone has put
> in
> > a
> > new Aircraft grade battery relay from an aircraft supply (Spruce)
source
> > battery relay in place of ours.
> >
> > I can currently remove the battery, diode and battery rely and get
> current
> > continuity (VOM) through the system from the positive cable to the
> > negative cable or any
> > ground... everything is off... i.e switches, breaker etc. This is what
> > some
> > people think is causing a "hum" in the radios. The "hum" is present
with
> > the engine off and running the radios off a fully charged battery. .
> > Additionally, using the AC voltage test setup on the VOM I can detect
> > current flow between the positive cable and ground... any ground.
> >
> >
> > I'm using certer point grounding, but all the avionics manual articles
> > point
> > to RMI induced noise through the hull by poor shielding on the DC power
> > lines.
> >
> > Beech doesn't seem to have these parts anymore.
> >
> > All comments welcomed...
> >
> > David J. Spencer
> > Super3
> > djs@54Transmission.com
> >
> >
>
>
Message 2
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| Subject: | Re: Battery Solenoid (Relay) |
--> Avionics-List message posted by: "Martini Luc J.R." <martini@foxinternet.net>
What was the reverse polarity reading? I assume since you did not give a
value for another range on the VOM, that it was a Digitial Type.
Do you have a 1 amp Current meter? From the ohmic check, that's about the
current you are drawing if this is a DC load. If not, hook a 100 ohm
resistor in series with the + battery Cable and measure the voltage drop
across the resistor.
As far as Radio noise in general GOOD GROUNDS (very low ohmic contact) are
EVERYTHING.
However, there are frequently 2 ground levels, SIGNAL ground and POWER
ground. Great care must be taken when assembling your avionics to keep
these two seperate, and connect them only at a SINGLE POINT ground.
It is not a bad idea to stick your head under the panel, and clean the
single point avionics ground to make sure the spade lugs and washers are
not oxidized (high ohmic contact)
It does not surprise me that with EXTERNAL DC power, that you do NOT have
radio hum. since your do NOT have a source of noise.. generator/alternator,
motors, etc.
You did not mention if it was the + or the - battery lead that had a crimp
splice in it. If it was in the + lead. other than creating a voltage
drop... which would be reflected to the voltage regulator, i.e. the
generator/alternator would be putting out more voltage than it should
because it senses a Battery slightly low voltage condition. If on the
other hand it was on the - side. as far as the radios go, it would be like
putting a resistance between the - battery terminal and Chasis Ground. This
could conceiveably cause the noise floor to be raised...but not likely if
yourGenrator/Alternator grouind is good... By the way... have to checked
that to make sure you have a good & clean grounding strap from the engine to
the firewall ??
Luc
ssage -----
From: "David J. Spencer" <djs@54Transmission.com>
Subject: Re: Avionics-List: Battery Solenoid (Relay)
> --> Avionics-List message posted by: "David J. Spencer"
<djs@54Transmission.com>
>
> Luc...
>
> There was approximately 11 ohms between the + & - with the correct
polarity
> hook up on the VOM.
>
> I took out the battery cable yesterday and found a split in the insulation
> about 3/8" long which had been taped over. The cable itself had been
> "crimped" creating a bulge and part of the internal wiring was broken at
> that point.
>
> As best I could tell this open area was not laying on the skin but ,
rather,
> pointing away from the skin as the cable lay on the belly of the plane.
>
> This is being corrected with new wiring and proper attachments.
>
> I hooked the radios up to a DC power source i.e. they are isolated from
> anything (except the antenna)... and the hum went away.
>
> David J. Spencer
> Super3
> djs@54Transmission.com
>
> ----- Original Message -----
> From: "Martini Luc J.R." <martini@foxinternet.net>
> To: <avionics-list@matronics.com>
> Subject: Re: Avionics-List: Battery Solenoid (Relay)
>
>
> > --> Avionics-List message posted by: "Martini Luc J.R."
> <martini@foxinternet.net>
> >
> > What resistance do you read between the battery cable and ground. Be
sure
> > to take the measurement with the leads swapped as well as standard
> polarity,
> > i.e. red lead to + and black to -.. If you are NOT using a digital VOM,
> > then also take values in both polarities in more than one RANGE on the
VOM
> > (active devices - diodes /transistors - are non-linear.. give you a good
> > clue if the value changes). You may have another noise suppression diode
> > somewhere, and/or an RC type (Band Pass) noise filter , with possibly a
> bad
> > capacitor in it.
> >
> > Let me know what you get.
> >
> > Luc Martini
> > ----- Original Message -----
> > From: "David J. Spencer" <djs@54Transmission.com>
> > To: <avionics-list@matronics.com>
> > Subject: Avionics-List: Battery Solenoid (Relay)
> >
> >
> > > --> Avionics-List message posted by: "David J. Spencer"
> > <djs@54Transmission.com>
> > >
> > > Hi all...
> > >
> > > Has anyone ever replaced the battery relay on their Beech A23-24 Super
> > III?
> > >
> > > My relay seems to work fine, but is 36 y/o and uses a Kipvolt Voltage
> > > suppressor (diode) to eliminate voltage spikes flushing through the
> > system.
> > >
> > > I am replacing the battery, ground and starter cables with new cable
> (AC
> > > grade #0 wire for the 40 amp system) and am wondering if anyone has
put
> > in
> > > a
> > > new Aircraft grade battery relay from an aircraft supply (Spruce)
> source
> > > battery relay in place of ours.
> > >
> > > I can currently remove the battery, diode and battery rely and get
> > current
> > > continuity (VOM) through the system from the positive cable to the
> > > negative cable or any
> > > ground... everything is off... i.e switches, breaker etc. This is
what
> > > some
> > > people think is causing a "hum" in the radios. The "hum" is present
> with
> > > the engine off and running the radios off a fully charged battery. .
> > > Additionally, using the AC voltage test setup on the VOM I can detect
> > > current flow between the positive cable and ground... any ground.
> > >
> > >
> > > I'm using certer point grounding, but all the avionics manual
articles
> > > point
> > > to RMI induced noise through the hull by poor shielding on the DC
power
> > > lines.
> > >
> > > Beech doesn't seem to have these parts anymore.
> > >
> > > All comments welcomed...
> > >
> > > David J. Spencer
> > > Super3
> > > djs@54Transmission.com
> > >
> > >
> >
> >
>
>
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