On Mon, 22 Sep 2003 22:56:02 +0100, Chris Wilson
wrote:

You can buy some sort of neon indicators from the electric
fence makers, but they are about 20 quid each...

Neon and a capacitor (maybe 0.22uF) in parallel, fed from a bridge
rectifier. Cost a quid or so.

--
Smert' spamionam

Andy Dingley wrote:

Neon and a capacitor (maybe 0.22uF) in parallel, fed from a bridge
rectifier. Cost a quid or so.

Why the capacitor? If the fence is pulsed, as all of ours are
(at ~ 1 Hz) then just a neon with a ~1M resistor works great.

--
Grunff

In article ,
says...
Andy Dingley wrote:

Neon and a capacitor (maybe 0.22uF) in parallel, fed from a bridge
rectifier. Cost a quid or so.

Why the capacitor? If the fence is pulsed, as all of ours are
(at ~ 1 Hz) then just a neon with a ~1M resistor works great.

Neon as in a mains tester screwdriver neon? Are neons different voltages?
The HT lead to the bird enclosure runs for about 40 yards, and passes
through the roof space of a shed, the fluorescent tube it passes by
"pulses" dimly, even when off. Pity it's in the shed, or that would do
VBG Thanks for replies. If the signal lamp was fairly bright could see
it from the house, which would be good.

--
Best Regards,
Chris.

Chris Wilson wrote:

Neon as in a mains tester screwdriver neon?

A mains tester screwdriver contains a neon bulb and a series
resistor. The neon bulb is just a small glass envelope with low
pressure neon and two electrodes


Are neons different voltages?

Not as such - you need to limit the current through them with a
resistor, the value of which will depend on your voltage.


If the signal lamp was fairly bright could see
it from the house, which would be good.

Depends what your HT circuit's like, but I suspect if you were
drawing that much power from it there wouldn't be much left to
mainain a good fence voltage.

--
Grunff

fred wrote:

10mA sounds like an awful lot for the neon (if the 10kV is right), you'll have
nothing left to zap the birds ;-). I was going to suggest 1mA from 4x2M2
high voltage resistors in series with a standard mains neon.

I don't reckon ours put out any more than 2-3kV once hooked up
to a few hundred metres of fence tape - much less in the wet.

--
Grunff

In article , Grunff
writes
fred wrote:

10mA sounds like an awful lot for the neon (if the 10kV is right), you'll have
nothing left to zap the birds ;-). I was going to suggest 1mA from 4x2M2
high voltage resistors in series with a standard mains neon.

I don't reckon ours put out any more than 2-3kV once hooked up
to a few hundred metres of fence tape - much less in the wet.

Ahhhhhhhh, theory and practice diverge again :-). Still, the HV resistors
are prob still a good idea, standard are prob only 500V . . . . Maplin codes
are 'V' +value , values 1M, 2M2, 4M7, 10M and are 3.5kV working, subject
to power rating.
--
fred

Andy Dingley wrote:

Depends on the earth, and the type of fence driver. If you have a low
earth impedance, and can get a decent voltage on the neon, then your
design will work. If the earth is lousy, then the rectifier-capacitor
design can charge up successive pulses until there's enough to flash
the neon.

True, very true.


There's a guy near my parents (West Lancs) who (like everyone around
there) has lots of glasshouses. In the Xmas runup, and to provide a
burglar alarm for the glasshouses, he keeps geese outside around them.
His fence has fluorescent tubes hung off it, which manage to flash
quite impressively. I've no idea what he drives the fence with, but
I'm not touching it....

Must be an interesting sight. A farmer not so far from here
drives his fences with old neon sign trannies. *OUCH*

--
Grunff

On Tue, 23 Sep 2003 00:51:28 +0100, Dave Plowman
wrote:

Why not do it at the low voltage side? Of course, this won't check that
the unit is actually working, but only switched on.

The usual need for a fence detector is to check that the wire hasn't
been broken.
--
Smert' spamionam

In article ,
Chris Wilson writes:
Would like some DIY means of having a visual light indicator that power
is on to an electric fence (well, fenceS actually), one around a chicken
run, using poultry netting, and the other wires around a 3/4 acre bird
enclosure. You can buy some sort of neon indicators from the electric
fence makers, but they are about 20 quid each... I was thinking something
about 2 quid each G. The potential on the wires is between 9 and 10 KV,
to a decent earth. Thanks.

Try a wire-ended neon, one end connected to fence and other end
just pointing away from the fence wire into the air. If it's too
dim, extend the wire pointing into the air. This is how some of
the much larger aircraft warning lamps strung along HV transmission
lines work -- the floating wire leaks enough current by corona
discharge and capacitively to light the lamps.

--
Andrew Gabriel

In article ,
Andy Dingley wrote:
Why not do it at the low voltage side? Of course, this won't check that
the unit is actually working, but only switched on.

The usual need for a fence detector is to check that the wire hasn't
been broken.

Ah. The OP simply asked for an indication that it was 'on'. And for
several fences.

--
*All men are idiots, and I married their King.

Dave Plowman London SW 12
RIP Acorn

Andy Dingley wrote:
On Tue, 23 Sep 2003 00:51:28 +0100, Dave Plowman
wrote:

Why not do it at the low voltage side? Of course, this won't check that
the unit is actually working, but only switched on.

The usual need for a fence detector is to check that the wire hasn't
been broken.

.... and/or that it hasn't been shorted out by falling debris, weeds,
etc.

--
Chris Green )

"Andy Dingley" wrote in message
...
On Tue, 23 Sep 2003 00:51:28 +0100, Dave Plowman
wrote:

Why not do it at the low voltage side? Of course, this won't check that
the unit is actually working, but only switched on.

The usual need for a fence detector is to check that the wire hasn't
been broken.

I take it that licking it (like we used to do with 9v batteries to check
them!) isn't a suitable option...

What sort of kick do these fences give? I've never had the misfortune to
experience one.

D

Andy Dingley wrote:

There's a guy near my parents (West Lancs) who (like everyone around
there) has lots of glasshouses. In the Xmas runup, and to provide a
burglar alarm for the glasshouses, he keeps geese outside around them.
His fence has fluorescent tubes hung off it, which manage to flash
quite impressively. I've no idea what he drives the fence with, but

He could attach a flashing neon to each goose, and hold a
Christmas rave...

--
jc

Remove the -not from email

In article ,
says...

I take it that licking it (like we used to do with 9v batteries to check
them!) isn't a suitable option...

What sort of kick do these fences give? I've never had the misfortune to
experience one.

D

The secret is the grab them manfully, then they aren't too bad, but I
don't recommend licking one :-)
I suspect there will be statutory limits on the voltage and current, but
I don't know what they are. The more powerful ones burn off vegetation as
it grows against them.

--
Best Regards,
Chris.

"David Hearn" wrote:

Hello David

DH| I take it that licking it (like we used to do with 9v
DH| batteries to check them!) isn't a suitable option...

The usual method on a farm of dealing with "know it all" types is to
simply not tell them about the electric fencing. Can give substantial
amusement. My dog ****ed on some once, he'd never go into that field
again.

DH| What sort of kick do these fences give? I've never had the
DH| misfortune to experience one.

Battery and Mains. The smaller 6v hobby jobs give enough to be felt.
12v car/leisure batteries kick out about 4-12kv (yep, kilo volts) at
absurdly low ampage. The mains one actually kick out *less* voltage,
but higher ampage and hurt considerably more and can energise miles of
wire.

The "hurt" is a typical electric shock. If you touch with your hand,
it hurts there and you get a deep pain followed by ache and tingling
at your wrist and ankle. Normally gone within a few minutes.
Apparently can be fatal to those with pacemakers by disrupting their
signal.

Kids don't seem to get hurt as bad, but older people do. I'm guessing,
but I figure this is down to resistance of the human body increasing
with age?

--
Simon Avery, Dartmoor, UK
uk.d-i-y FAQ: http://www.diyfaq.org.uk/

(Steve Firth) wrote:

Hello Steve

Battery and Mains. The smaller 6v hobby jobs give enough
to be felt. 12v car/leisure batteries kick out about
4-12kv (yep, kilo volts) at absurdly low ampage. The mains
one actually kick out *less* voltage, but higher ampage
and hurt considerably more and can energise miles of wire.

SF| "Ampage" - the term you are searching for an failing to
SF| identify is "current".

Are you sure?

SF| 12V car batteries do not "kick out 4-12kV" they supply
SF| approximately 12V (usually about 12.3-12.8V). An electric
SF| fence run from a 12V battery will supply several kV from the
SF| coil.

Which is what I said.

Guys, if anyone wants a demonstration of the effect of either battery
or mains powered electric fencing, I'm /more/ than happy to connect it
to petty minded pedants. I'm genuinely curious as to the restistivity
of hot-air laden, anal retentive water bags when used as earthing
poles.

--
Simon Avery, Dartmoor, UK
uk.d-i-y FAQ: http://www.diyfaq.org.uk/

Steve Firth wrote:

SF| 12V car batteries do not "kick out 4-12kV" they supply
SF| approximately 12V (usually about 12.3-12.8V). An electric
SF| fence run from a 12V battery will supply several kV from the
SF| coil.

Which is what I said.

Well, no it isn't, your comment is reproduced above if you're unsure of
that.

Hate to butt in on this little tet-a-tet, but while Simon did
write "12v car/leisure batteries kick out about 4-12kv (yep,
kilo volts) at absurdly low ampage", I (and undoubtedly many
others) understood that he meant the fence units powered by 12v
batteries.

As for use of the word ampage - while it's more correct to say
current, saying ampage or amperage is pretty commonplace, and
understood by most.

So it was all a simple misunderstanding. Group hug?

--
Grunff

In article ,
says...
In article ,
says...
Andy Dingley wrote:

Neon and a capacitor (maybe 0.22uF) in parallel, fed from a bridge
rectifier. Cost a quid or so.

Why the capacitor? If the fence is pulsed, as all of ours are
(at ~ 1 Hz) then just a neon with a ~1M resistor works great.

Neon as in a mains tester screwdriver neon? Are neons different voltages?
The HT lead to the bird enclosure runs for about 40 yards, and passes
through the roof space of a shed, the fluorescent tube it passes by
"pulses" dimly, even when off. Pity it's in the shed, or that would do
VBG Thanks for replies. If the signal lamp was fairly bright could see
it from the house, which would be good.



Sorted now, and I feel a bit of a fool. Being in the motor trade I should
have realized that a drawer in the workshop contained a spark indicator
neon to go onto spark plug leads to check for HT to a plug. Worked fine,
zero cost. Sincere thanks for all the replies!
--
Best Regards,
Chris.