Humming Alarm Panel

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TheScullster

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May 29, 2008, 10:13:00 AM5/29/08
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Hi all

Recently fitted a Texecom Excel panel and noticed that the transformer has a
very audible hum!
Does this suggest weakness?
My previous panel (Pyronix Super) was silent.
Does the size of battery fitted have any relevance - I increased the battery
from 1.2Ah in the old panel to 7Ah in the new one.

TIA

Phil


Harry Bloomfield

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May 29, 2008, 12:18:08 PM5/29/08
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After serious thinking TheScullster wrote :

> Hi all
>
> Recently fitted a Texecom Excel panel and noticed that the transformer has a
> very audible hum!
> Does this suggest weakness?

The hum could be either loose laminations on the transformer, or mains
hum noise coming from a speaker/sounder. You need to work out which of
the two first.


> My previous panel (Pyronix Super) was silent.
> Does the size of battery fitted have any relevance - I increased the battery
> from 1.2Ah in the old panel to 7Ah in the new one.

If the battery was not fully charged when installed into the unit, then
it might be taking more current than usual to charge it up and thus
might be causing some of the hum.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk


mmzz

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May 29, 2008, 5:11:43 PM5/29/08
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i think you will find four screws holding the transformer. give them a
tweak

cj

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May 29, 2008, 6:02:43 PM5/29/08
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Hi
Another common cause is if the panel is not fitted to a flat surface or a
cable fouls it against the wall.
Try light pressure against each corner & see if the hum increases or goes.As
for battery IIR the Excell range will support a 7ah no problem if in doubt
try
www.text.com they are very helpful.

CJ


meow...@care2.com

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May 29, 2008, 6:30:51 PM5/29/08
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Hum is occasionally a problem with mains transformers.
1. Tke a hammer & cold chisel, and give the laminations a whack
on each side. This jams the lams together, stopping hum.
2. Mount the transformer on rubber washers and it'll be much
quieter.


NT

TheScullster

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May 30, 2008, 7:20:54 AM5/30/08
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<meow...@care2.com> wrote

>
> Hum is occasionally a problem with mains transformers.
> 1. Tke a hammer & cold chisel, and give the laminations a whack
> on each side. This jams the lams together, stopping hum.
> 2. Mount the transformer on rubber washers and it'll be much
> quieter.
>
>

Thanks to all.
Prefer the sound of tweaking the transformer screws rather than hitting the
thing with a hammer and chisel.
The panel is already mounted off the wall on flexible packers.

Phil


dennis@home

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May 30, 2008, 8:30:45 AM5/30/08
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"TheScullster" <ph...@dropthespam.com> wrote in message
news:XPSdnT8mhf9xfKLV...@eclipse.net.uk...

Doing that may make it worse.

Harry Bloomfield

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May 30, 2008, 2:26:47 PM5/30/08
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TheScullster formulated on Friday :

> Thanks to all.
> Prefer the sound of tweaking the transformer screws rather than hitting the
> thing with a hammer and chisel.
> The panel is already mounted off the wall on flexible packers.

Rather than hitting the laminations with a hammer....

On these small transformers there is usually a soft metal strap
surrounding the laminations which is U shaped. Squeeze the sides of the
U, perhaps in a vice.

Stephen Dawson

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May 30, 2008, 3:15:40 PM5/30/08
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"cj" <m...@here.com> wrote in message news:E-adndMH3dm...@bt.com...

or even www.texe.com

Rgds

Steve


cj

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May 30, 2008, 4:51:44 PM5/30/08
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OOPS!!
sorry typo

CJ


The Natural Philosopher

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May 30, 2008, 5:19:29 PM5/30/08
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Harry Bloomfield wrote:
> TheScullster formulated on Friday :
>> Thanks to all.
>> Prefer the sound of tweaking the transformer screws rather than
>> hitting the thing with a hammer and chisel.
>> The panel is already mounted off the wall on flexible packers.
>
> Rather than hitting the laminations with a hammer....
>
> On these small transformers there is usually a soft metal strap
> surrounding the laminations which is U shaped. Squeeze the sides of the
> U, perhaps in a vice.
>
dribble epoxy resin into the transformer.

meow...@care2.com

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May 31, 2008, 11:01:23 AM5/31/08
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TheScullster wrote:
> <meow...@care2.com> wrote

One of those will work for you, one wont. We dont know which
until you try them. Hammering lams is standard practice for
silencing noisy transformers. Obviously one removes the thing
from the kit first :) Pointed chisel required, not a flat edged one.


NT

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