Author Topic: Electric fence with an unknnown component  (Read 569 times)

0 Members and 1 Guest are viewing this topic.

Offline gg64

  • Contributor
  • Posts: 43
  • Country: fr
Electric fence with an unknnown component
« on: September 21, 2018, 11:57:29 am »
Hi there.

I am very new on the eeblog forum :).

So I got an electric fence (for cattle) that I am trying to repair.

The advertised specs are: 3Joules, 10kV.

Though I did not checked it, it was able to make quite a spark.


So it started to be really about weeks ago, it would not even show any sign
 of voltage onto the purposely designed voltmeter (basicaly I think this is just a bunch of
lamp with different resistance on them: I will call the ACME tester).

So after some test with it, I concluded it was the pulse coil that was deffective.

So I order a transformator (pulse transformator) core from ebay, received it.

I coiled it as at least like the former one (ratio of 10/1).

I tested with 10/1 nothing (onto the ACME tester) but it was able to make a small spark.

So I decided to go for 20/1, then I can see the lamps flashing onto the ACME tester.


After discussion with the user, we decided to ramp up to 30/1. Still working onto the ACME tester.


So I put some tips on the transformer (to make final installation).

I connected again the transformer with the load but I thought I plug correctly the transformer's primary (I DID NOT...)


I heard a tick sound.

So after some trouble shooting I concluded that the bt139-600 should be fried.

I bought 5 from ebay (along with some diodes (20x) em516 and a condensator 400vac 1µF).

1st try: Installed one the board, fried (not when connecting with the old tranformer the new one, with 30/1 ratio)

2nd try: Installed one the board, fried (not when connecting with the old tranformer the new one, with 10/1 ratio)

3nd try: Installed one the board, fried (not when connecting with the old tranformer the new one, with 1/1 ratio)

I measured 18kohm onto the old transformer, and the capacitor (in serial with the pulse tranformer) was reaching about 420v.


I decided that's enough. I should seek help. I am missing something.

Please note, according to the writing the fence should not go quicker than about 1Hz (he does: about 901ms period)

Here the schematics I reversed engineering except one components I can't figure what his specs are, is this a diode ?

(I got an idea but I don't want to skew people's opinion)


The "diode?" got a blue stripe right in the middle, I would like to know the value is supposed to be.

Here as join piece a QUCS schematic with the component named "whoami".

A photo with the unknown "diode?" circled in red (my cameras on my smartphone are dead, so no real nice close up photo yet, this is taken from a webcam)


Btw the simulation is not working for some reason (on QUCS) but it is basicaly a power side (left on the photo) and a pulse control side (right)

Also, I don't have osciloscope (i wish I had one....), no attenuation device, just multimeters able to go 600v and a capacitor meter.


QUESTION:
Does anyone can identify the compenent named "whoami" on the schematics (red circle on the photo) ?

I would be really thankful. :)
« Last Edit: January 18, 2019, 07:13:38 am by gg64 »
 

Offline gg64

  • Contributor
  • Posts: 43
  • Country: fr
Re: Electric fence with an unknnown component
« Reply #1 on: September 21, 2018, 12:01:53 pm »
I didn't understand how to put several attachements as a first post, sorry. (missed the more attachments button)

Here are the rest.
 

Offline capt bullshot

  • Super Contributor
  • ***
  • Posts: 1690
  • Country: de
    • Mostly useless stuff, but nice to have: wunderkis.de
Re: Electric fence with an unknnown component
« Reply #2 on: September 21, 2018, 12:04:03 pm »
Can't find a schematic within you post ...
As a wild guess from the photo and your description saying the circuit uses a Triac (the BT139), it might be a DIAC (triggering device). Especially if one end is connected to the Triac Gate.
Safety devices hinder evolution
 
The following users thanked this post: gg64

Offline gg64

  • Contributor
  • Posts: 43
  • Country: fr
Re: Electric fence with an unknnown component
« Reply #3 on: September 21, 2018, 12:12:35 pm »
I forgot an attachements sorry, check the schematic as a second post. :)

I am trying to revive up an old smartphone, to take a clear close up photo. :)
 

Offline tpowell1830

  • Frequent Contributor
  • **
  • Posts: 750
  • Country: us
Re: Electric fence with an unknnown component
« Reply #4 on: September 21, 2018, 12:14:06 pm »
I would say it is a zener diode from the awful, out of focus, low light photo. No way to tell what value zener.
PEACE===>T
 
The following users thanked this post: gg64

Offline gg64

  • Contributor
  • Posts: 43
  • Country: fr
Re: Electric fence with an unknnown component
« Reply #5 on: September 21, 2018, 12:47:14 pm »
Here are some close up photos of the board.

https://imgur.com/a/H1LAujC
 

Offline MK14

  • Super Contributor
  • ***
  • Posts: 2152
  • Country: gb
Re: Electric fence with an unknnown component
« Reply #6 on: September 21, 2018, 01:16:43 pm »
Here is one picture of a Diac. Someone else mentioned Diac in this thread as well.
Diacs often go with Triacs, as they make nice triggering devices.

« Last Edit: September 21, 2018, 01:24:22 pm by MK14 »
 
The following users thanked this post: gg64

Offline gg64

  • Contributor
  • Posts: 43
  • Country: fr
Re: Electric fence with an unknnown component
« Reply #7 on: September 21, 2018, 01:25:27 pm »
Oh, I never seen those. Thanks you, it seems to check out.

I know this is an english speaking forum but according to this website (in french, yes I am French deal with it  :) ):

https://www.astuces-pratiques.fr/electronique/le-diac-composant-electronique

It is common to use diac with a triac.

Here the same kind of information in english:

https://www.electronics-tutorials.ws/power/diac.html

So that will point me to check the power resistors I guess ? (not sure about it just yet....)
« Last Edit: January 18, 2019, 07:10:10 am by gg64 »
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf