Author Topic: Protect your gear from over-voltage with EASY CIRCUIT  (Read 6463 times)

Offline Carl

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Protect your gear from over-voltage with EASY CIRCUIT
« on: December 10, 2014, 05:24:01 AM »
Protect from overvoltage from power supply problems to lightening transients...
Many,especially switching / transformerless power supplies ,when they fail...or are effected by nearby RF, will output dangerously high voltages to your expensive HAM and other gear.
Here is a simple way to protect your gear from these HORRORS..and it is CHEAP AND EASY.

https://drive.google.com/file/d/0B5ZIZLZV4AwIVDdKWTBnazhRRGc/view?usp=sharing

Note that though 'glass ' fuses are illustrated,I use the more modern BLADE FUSES in holders.

Offline Special K

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #1 on: December 10, 2014, 09:37:37 AM »
:popcorn:

Offline Smurf Hunter

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #2 on: December 10, 2014, 09:50:36 AM »
For the lazy folks, I created a "project" on the mouser website that has all the parts.

I added all the components to the letter from the PDF (including the old school glass fuses and holders).
I also added extra diodes, as they are cheap and not something you can easily improvise.

1) open http://www.mouser.com/Tools/Tools.aspx
2) "Enter Access Id:"  236d0f4432
3) tweak shopping cart contents as desired
3) buy


Offline Smurf Hunter

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #3 on: December 10, 2014, 09:55:17 AM »
Carl,

I was thinking it might be a neat idea to combine this project with a volt/amp meter.  It would only require a larger enclosure.  And those LED displays cost almost nothing.

It would seem a redeeming feature of the glass fuses is the neat little holder seems to take up less space inside an enclosure.

Offline Carl

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #4 on: December 10, 2014, 10:05:14 AM »
Carl,

I was thinking it might be a neat idea to combine this project with a volt/amp meter.  It would only require a larger enclosure.  And those LED displays cost almost nothing.

It would seem a redeeming feature of the glass fuses is the neat little holder seems to take up less space inside an enclosure.

The new DIGITAL meter would indeed be a great addition, But I would suggest external BLADE fuses in inline holders as easy access...though they are only supposed to blow when HELL freezes over and your power source goes wacky...just my habit...your 'all in one' would make for a neat ,multi-use (maybe add multiple output terminals?) all in a box savior.

Your gear deserves this cheap protection.

Offline Smurf Hunter

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #5 on: December 10, 2014, 10:16:51 AM »
The new DIGITAL meter would indeed be a great addition, But I would suggest external BLADE fuses in inline holders as easy access...though they are only supposed to blow when HELL freezes over and your power source goes wacky...just my habit...your 'all in one' would make for a neat ,multi-use (maybe add multiple output terminals?) all in a box savior.

Your gear deserves this cheap protection.

Would inline blade vs. glass tube fuses of equal current rating behave differently? 
e.g. 25amp of either style SHOULD blow if we sent 40amps across them - right?

For the record, I have inline fuses on all my radios.

Offline Carl

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #6 on: December 10, 2014, 10:54:17 AM »
Would inline blade vs. glass tube fuses of equal current rating behave differently? 
e.g. 25amp of either style SHOULD blow if we sent 40amps across them - right?

For the record, I have inline fuses on all my radios.

The element is the same length,it should react the same way,but I say use 'em if you got 'em ...I like inline blade fuses because I have had several failures of inline glass fuse holders (NOTE, my failures were from inline holders,NOT the clip style holder used in this project)

I like the weather/dust resistant blade holders and have a BUNCH on hand...also bought many 100 plus fuse assortments for about FIVE CENTS A FUSE and so I LIKE THEM BETTER. Just do not use SLOW-BLOW fuses or circuit  breakers (yes ,they make 12 volt ,blade type breakers) as they would not blow fast enough to protect your gear.

Big PLUS is the NEW INDICATOR blade fuses that light an internal LED to tell you the fuse is blown, (you can do this with a 12 volt LED (LED and resistor) across the fuse to indicate a blown fuse)

Offline backwoods_engineer

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #7 on: December 16, 2014, 03:26:08 PM »
So, it's a fuse holder with a transzorb?

Unless you reverse the input leads, or the radio pulls too much current, the fuses probably aren't going to blow.   A brief (<1mS) surge on the 12V input will be clamped by the transzorb, and the fuses won't heat up enough to blow.

Offline Carl

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #8 on: December 16, 2014, 03:47:52 PM »
So, it's a fuse holder with a transzorb?

Unless you reverse the input leads, or the radio pulls too much current, the fuses probably aren't going to blow.   A brief (<1mS) surge on the 12V input will be clamped by the transzorb, and the fuses won't heat up enough to blow.

At 15 volts ,the diode clamps to an equivalent SHORT CIRCUIT and the fuses WILL BLOW..
 ,it is a 1500 watt ZENER, It is way better than NO PROTECTION and will do the job of protecting gear.

Offline TiredOldGrunt

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #9 on: December 16, 2014, 06:42:56 PM »
Note: Suitable for over voltage or voltage spike
Note: Not suitable for EMP

My crystal ball already sees that question coming.. arrrggg!

Offline Smurf Hunter

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #10 on: December 16, 2014, 10:58:44 PM »
Note: Suitable for over voltage or voltage spike
Note: Not suitable for EMP

My crystal ball already sees that question coming.. arrrggg!

I am reading One Second After this week.  Terrifying story but I'm not a big believer in EMP prep.

Offline Carl

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #11 on: December 17, 2014, 03:55:11 AM »
I am reading One Second After this week.  Terrifying story but I'm not a big believer in EMP prep.

But you forget...GREMLINS...don't feed them after midnight! Don't get them wet either.

Offline exSun

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #12 on: December 24, 2014, 10:58:11 AM »
So why the fuse in the negative lead? It's on the wrong side of the transorb for it to blow on over-voltage. And I thought the place for a fuse in the negative lead was near the battery or power supply, not the radio.

Offline Carl

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #13 on: December 24, 2014, 11:01:49 AM »
You get TWO chances that ONE will blow BEFORE your radio is damaged,,,most radios are fused on BOTH wires also.

Offline exSun

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #14 on: December 27, 2014, 10:03:33 AM »
You get TWO chances that ONE will blow BEFORE your radio is damaged,,,most radios are fused on BOTH wires also.

Not if the fuse is put where it is shown - between the transorb and the radio. The fuse must be between the power source and the transorb if it is to blow when the transorb conducts.

Offline Carl

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #15 on: December 27, 2014, 10:20:11 AM »
I guess you just don't already have fuses in line for your radio? This simple circuit works Please stop trying to tear it apart before you have built it.

Offline exSun

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #16 on: December 27, 2014, 10:23:27 AM »
I guess you just don't already have fuses in line for your radio? This simple circuit works Please stop trying to tear it apart before you have built it.

I think it is a great circuit! I'm just trying to get it shown correctly. I'll email Phil Sallas - but I think he intended to show both fuses between the transorb and the power source.

Offline Carl

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #17 on: December 27, 2014, 10:39:12 AM »
I think it is a great circuit! I'm just trying to get it shown correctly. I'll email Phil Sallas - but I think he intended to show both fuses between the transorb and the power source.

As it is drawn,it protects against BOTH OVERVOLTAGE(15V) and REVERSE VOLTAGE from people who don't know RED from Black. Feel free to add to it , but simple is how I like things.

Offline exSun

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Re: Protect your gear from over-voltage with EASY CIRCUIT
« Reply #18 on: December 27, 2014, 12:57:03 PM »
I asked Phil Salas, the creator of the circuit. Here is his reply:
Quote
Hi ... - Actually, I don't think the negative fuse is even needed.  I
put it where it is so that if an over-voltage or reverse voltage
condition occurred, it would just blow the positive fuse. The only
reason I showed the negative fuse is because most radios include this in
the power lead.
73,
Phil - AD5X

So it really just represents the existing radio fusing.