Resistor vs Transformer update

[John Fields]

"John Fields"
"Paul E. Schoen"



** The OP is almost certainly a TROLL.

Bet he has exactly one, Asian sourced, 120 volt alarm system.

---
If he was a troll, why would he even have to have one? All he'd
have to do would be to make it all up.

You know, like you often do...
---

 

[John Fields]

Paul .
Their equivalent circuit is 2 back to back zener diodes... thats why
their behaviour is what I outlined above.
They are protective devices , so if they short at excess voltages the
whole circuit will blow up which isn't the intention why they are
used.

---
Once again you're full of misinformation, and the parallel between
MOV's and series-opposed Zeners is not a good one, especially
considering the MOV's inherent wearout mechanism, which doesn't
plague Zener-based TVS devices.
---

 

[Fred Bloggs]

---
If he was a troll, why would he even have to have one? All he'd
have to do would be to make it all up.

You know, like you often do...
---

He *is* a troll- not German at all, and posting from US under fake troll
name using troll favorite Forte Agent- what is more- indicates
familiarity with sed regulars.

 

[Rich Grise]

On Fri, 17 Feb 2006 18:51:35 -0500, "Paul E. Schoen"


What I'm amazed at is that the OP's boss (who must be technically
even less competent than the OP) has let him have such a long leash.

Essentially, a novice has been given the responsibility for making
critical technical decisions which can adversely affect human life
and the protection of property with, apparently, no technical
supervision whatever.

Pretty scary.

I think you're both spot-on, which is why I bailed from the thread
some days ago. I had my input: "Transformers." and OP didn't listen.

Guess that's another reason why it's so rewarding when they _do_.

Cheers!
Rich

 

[Rich Grise]

Ah then the mystery is solved. Now the hard work of finding what
technology is used in the originals.

I am also having a problem in replacing the varistor. The original had a
limit at 130V , so I assume the new one should be about 250V but my
supplier also needs a resistance value. The load which is mostly
resistive has an actual power value of around 300Watts. Before I spend
hours checking on datasheets of MOVs , has anybody had a detailed
experience with this problem.

MOVs are 19th century technology. They're crap. They wear out. They
blow up. Get rid of them. I can't even imagine why anybody's still
making the stupid things.

Use a Transzorb:
http://www.vishay.com/diodes/protection-tvs-esd/trans-zorb/

They come in AC varieties, which is just back-to-back diodes in one
package. It's basically a Zener (or breakdown diode, or avalanche,
or whatever the proper technical term is) that can handle huge
transients without blowing up. And dissipating a transient doesn't
"use up" a transzorb, like it does an MOV. (It just takes the heat
and dissipates it over time.) I've used them, and I'll swear by them
for transient protection. Unlike MOVs, which I've been known to
swear _at_. ;-)

I don't work for Vishay, or GI, who used to make them (or used to
_exist_ ;-) ); I'm just a happy customer.

Good Luck!
Rich

 

[Rich Grise]

Once again you're full of misinformation, and the parallel between
MOV's and series-opposed Zeners is not a good one, especially
considering the MOV's inherent wearout mechanism, which doesn't
plague Zener-based TVS devices.


Well, then, you must be very close to being an expert in _all_ of
your endeavors.

Let's not be hasty here - it takes a long time to even discover most
of the possible mistakes, let alone make enough to ensure that there
isn't another possible mistake! ;-)

And frankly, if that criterion really would apply, I'm about at the
point where I know everything about everything. ;-P

Ergo, it's probably not true. )-; [ ;-) ]

Cheers!
Rich
--
Elect Me President in 2008! I will:
A. Fire the IRS, and abolish the income tax
B. Legalize drugs
C. Stand down all military actions by the US that don't involve actual
military aggression against US territory
D. Declare World Peace I.

 

[lemonjuice]

LOL.Face facts 99% OF the regs here are trolls
Isn't the Pope German?

He might be the Pope as far as I can tell his IP address is in the
Vatican.

lemonjuice

 

[John Fields]

Let's not be hasty here - it takes a long time to even discover most
of the possible mistakes, let alone make enough to ensure that there
isn't another possible mistake! ;-)

And frankly, if that criterion really would apply, I'm about at the
point where I know everything about everything. ;-P

 

[lemonjuice]

MOVs are 19th century technology. They're crap. They wear out. They
blow up. Get rid of them. I can't even imagine why anybody's still
making the stupid things.

That is one of the myths you find in the Electrical Power community.
I'd say the fact that they are used is proof of a superior engineering
insight to the average
Varistors come with different power and voltage specs. If you put the
wrong MOV in a circuit it blows up and thank God that it does!
But gosh if the WTC Towers could be blown up I wouldn't be surprised if
MOVs can. About MOVs wearing out ... I don't know of anything in the
Electronics field or any other field which doesn't.

lemonjuice

 

[Ancient_Hacker]

Sorry to disagree with you:

MOV's can be made into almost any size, with a lot of thermal inertia.
Zeners can't.
Personally if I was expecting many-joule transients I'd rather have 1
big honkin Kruggerrand-sized MOV than a pinhead-sized Zener. On
digi-key they have MOV's good for up to 60,000 Amps, but the zeners
only go up to 600 watts.

MOV's are typically used in applications where there are relatively
few, low duty-cycle transients, such as turn-on/off transients.
Obviously you shouldnt put in a surrpressor that's too small to handle
the transients. But in the typical across-the-line application you
don't see 300 volt transients many times a second. Or else you have
bigger problems.

In any case the poor original poster should make sure he gets AC
line-rated varistors, not some wimpy telephone line signal-rated ones.
AND that he's talking about the right kind of varfistor-- sometimes
that name is used for the negative-temp coefficient thermistors that
are often right next to the AC line clipping varistors. You don't want
to substitute one for the other.

 

[Phil Allison]

"John Fields"

I see being up early doesn't do much for your disposition either!

** My message was posted on Saturday at 11:23pm, Sydney time.

Ever get anything right - fuckhead ?

Anyway, I stand corrected,

** While lying out you arse.

Sorry, Charlie,

** **** you - asshole.

it depends on a lot more than just how much power
(OK, Volt-Amperes) they can transfer.

** Meaningless drivel.

( snip idiotic 6MB pdf posted in lieu of fact )

So you think the OP's using a 160VA transformer to run his 6 watt
receiver?

** Complete non sequitur.

As usual from a desperate bloody liar.



" John Fields
Professional Bullshit Artist "





.......... Phil

 

[John Fields]

"John Fields"


** My message was posted on Saturday at 11:23pm, Sydney time.

---
That's not early for you?
---

Ever get anything right - fuckhead ?

---
Sure. Most of the time.
---

** While lying out you arse.

---
You don't believe me?

Ok, then I _don't_ stand corrected.

Happy now?
---

** **** you - asshole.

---
I see. I present you with facts and you reply with vindictive.

Aside from refusing to acknowledge the fact that you were wrong with
your statement that:

"Only transformers of 5 VA or less have such poor regulation."

You choose to duck the issue and to reply with language which is
_certainly_ not polite, and will surely brand you as being quite an
inconsiderate person.
---

** Meaningless drivel.

( snip idiotic 6MB pdf posted in lieu of fact )

---
I notice that your "refutation" is, indeed, devoid of fact and, by
your snippage, would have us believe that your lack of presentation
of a technical refutation places you above above that requirement.

In actuality, your refusal to address the issue smacks of your being
unable to.
---

** Complete non sequitur.

As usual from a desperate bloody liar.

---
Not at all.

You stated that a 160VA transformer is normally specified to
regulate the output voltage to within 6% and implied that smaller
transformers exhibited poorer regulation. Therefore, if that's
true, the OP's transformer, with a claimed regulation of 6% must
_not_ be rated for less than 160VA.

If you don't understand the logic behind that, just ask me to
explain it further, and I'll try to dumb it down a notch or two for
you.
---

 

[Terry Given]

John Fields wrote:
[snip]

but small transformers usually run about 30%, no load
to full load.


** What ignorant crapology !!!!!!!!!!!!!!!!!

Only transformers of 5 VA or less have such poor regulation.

[snip]
A 50 VA tranny is normally speced at 10% and a 160 VA 6%.


So you think the OP's using a 160VA transformer to run his 6 watt
receiver?

** Complete non sequitur.

As usual from a desperate bloody liar.

---
Not at all.

You stated that a 160VA transformer is normally specified to
regulate the output voltage to within 6% and implied that smaller
transformers exhibited poorer regulation. Therefore, if that's
true, the OP's transformer, with a claimed regulation of 6% must
_not_ be rated for less than 160VA.

If you don't understand the logic behind that, just ask me to
explain it further, and I'll try to dumb it down a notch or two for
you.
---

" John Fields

I've seen a 14% 2MVA transformer before. A small fuckup at ABB, and the
customer bought it because it was *cheap*

Cheers
Terry

 

[Phil Allison]

" John Fields
Professional Bullshit Artist "


Says it all really.

Except for the fact he is Texas psychopath too.




.......... Phil

 

[John Fields]

" John Fields
Professional Bullshit Artist "


Says it all really.

Except for the fact he is Texas psychopath too.

 

[Michael A. Terrell]

---
LOL, _I'm_ not the one sitting at a keyboard 24 hours a day hurling
insults at anyone who passes by.

PKB, dear boy!

John, check out Phil's webcam! ;-)
http://www.fugly.com/media/view.php?cat=MOVIES&id=4766
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida