Kohler 6.5KW CZ generator blowing fuse
GSS
the 10 amp input fuse whenever I shut it down from the engine mounted
or remote kill switches. It then won't restart until I install a new
fuse. Does anyone have any idea what would be causing this? The unit
starts & runs fine, and for now, I stop it by removing the fuse and
then replace it once it is shut down.
There is a second fuse, but this goes to the battery charging system
and seems to be unaffected by the stopping sequence. I have this
posted to a couple of boating & RV groups so I hope someone can help
me on it. Please feel free to respond to my email directly if you're
reluctant to respond to the group.
Thanks in advance.
Eisboch
"GSS" <gssmi...@yahoo.com> wrote in message
news:dfd0d351-4ceb-425e...@e6g2000prf.googlegroups.com...
Obviously the "kill" switch energizes a relay or solenoid to either
interrupt ignition or fuel. I am not familiar with gas generators but on a
diesel, the kill switch usually energizes a fuel supply solenoid. I'd
look to see what that fuse is supplying power to and I suspect whatever it
is ... is bad.
Eisboch
Steve Lusardi
damage both the generator or the load. Perhaps there is an automatic
disconnect that is now not functioning. Try manually unplugging all loads,
then shutting down.
Steve
"GSS" <gssmi...@yahoo.com> wrote in message
news:dfd0d351-4ceb-425e...@e6g2000prf.googlegroups.com...
Chuck Gould
> "GSS" <gssmith1...@yahoo.com> wrote in message
Could an improper ground of the controlled component cause the blown
fuse, or would it be more likely that the component itself is gunny
sack?
As an electrical duffer, my other horseback guess might be a short
circuit in the wiring connecting the switches to the controlled shut-
off component. Could the generator be stopping because the fuse is
blown by bad wiring in the control circuit rather, than due to any
reaction to the switch(es)?
Eisboch
"Chuck Gould" <chuckgou...@gmail.com> wrote in message
news:fe6bdf28-1125-46e2...@f10g2000hsf.googlegroups.com...
On Jan 26, 6:15?am, "Eisboch" <r...@nowhere.com> wrote:
> "GSS" <gssmith1...@yahoo.com> wrote in message
>
> news:dfd0d351-4ceb-425e...@e6g2000prf.googlegroups.com...
>
> >I have a gas powered 6.5 KW Kohler generator Model 6.5CZ that blows
> > the 10 amp input fuse whenever I shut it down from the engine mounted
> > fuse. ?Does anyone have any idea what would be causing this? ?The unit
> > starts & runs fine, and for now, I stop it by removing the fuse and
> > then replace it once it is shut down.
>
> > There is a second fuse, but this goes to the battery charging system
> > posted to a couple of boating & RV groups so I hope someone can help
> > reluctant to respond to the group.
>
> > Thanks in advance.
>
> Obviously the "kill" switch energizes a relay or solenoid to either
> a
> diesel, the kill switch usually energizes a fuel supply solenoid. ? ?I'd
> look to see what that fuse is supplying power to and I suspect whatever it
> is ... is bad.
>
> Eisboch
Could an improper ground of the controlled component cause the blown
fuse, or would it be more likely that the component itself is gunny
sack?
As an electrical duffer, my other horseback guess might be a short
circuit in the wiring connecting the switches to the controlled shut-
off component. Could the generator be stopping because the fuse is
blown by bad wiring in the control circuit rather, than due to any
reaction to the switch(es)?
Giving the OP's post more thought,
If the generator shuts down ok by *removing* the 10 amp fuse that normally
blows if using one of the kill switches, it suggests that a solenoid or
something is *energized* while running. The kill switches must interrupt
the power to something .... same as removing the fuse.
Therefore, I'd probably be looking for a wiring problem.
Eisboch
Brian Whatcott
wrote:
What's an "input fuse"?
I may be blowing wind, and I have no experience of this rig,
but a mechanism that comes to mind is this:
the engine slows, the generator volts drop, and the field regulator
boosts the current to hold the output voltage, blowing a field current
fuse.
Brian W
GSS
> "Chuck Gould" <chuckgould.ch...@gmail.com> wrote in message
>
> - Show quoted text -
Thinking it through, I believe the kill switch grounds the voltage
from the coil voltage to the block, so it doesn't reach the spark
plug...before it gets to the spark plug, shorting the voltage between
the coil and the spark plugs, which ceases the spark, and causes
GSS
won't run. It is only a 10 amp fuse so I don't think the power for
the starter runs THRU the fuse, but the fuse must protect some sort of
contactor or solenoid which closes the circuit for the starter. I
thought there might be something on the toggle switch that is
shorting, but it seems to blow the fuse whether the remote kill switch
or unit mounted switch is used to kill the generator.
Eisboch
I am not an expert and there are others here that may have more exact
knowledge, but I think your starter solenoid is bad.
Eisboch
Bob AZ
> Thanks in advance.
Fuses have other characteristics than Amps. What type does the owners
manual recommend?
Wayne.B
>If the generator shuts down ok by *removing* the 10 amp fuse that normally
>blows if using one of the kill switches, it suggests that a solenoid or
>something is *energized* while running. The kill switches must interrupt
>the power to something .... same as removing the fuse.
I have an Onan diesel generator that works pretty much as you
describe. There is a solenoid which must be activated for the
generator to start and continue running. If an over temp or low oil
pressure sensor trips, power to the solenoid is interuppted and the
generator stops. It will not restart until a reset button is pressed.
When you press the stop button, a relay is activated which interrupts
power to the solenoid. My guess would be a short circuit or defective
shut down relay.
Richard Casady
<waynebatr...@hothail.com> wrote:
>>If the generator shuts down ok by *removing* the 10 amp fuse that normally
>>blows
My Maytag washer and drier have the wiring diagrams pasted to the
inside of the removable sheet metal access panels. Maytag is no more,
unfortunately.
Casady
Don White
"Richard Casady" <richar...@earthlink.net> wrote in message
news:479db053....@news.east.earthlink.net...
Whirlpool still use the Mmaytag name but the appliances aren't what they
used to be... re massive recall last year.
wwe...@mungedhughes.net
Maytag is still very much in business. Check <http://www.maytag.com>
In addition they own many other brands such as Whirlpool, Amana, etc.
George
--
Posted via a free Usenet account from http://www.teranews.com
Paul Mann
was here in Iowa has been closed and sold. Maytag is now made in
Whirlpool factories.
Paul in Iowa
Don White
<wwe...@mungedhughes.net> wrote in message
news:luhpp3h9vveccutf8...@4ax.com...
I know this because I was one of those affected by the inner door/control
panel fiasco last year. Finally got a new dishwasher out of it.
GSS
> <wwe...@mungedhughes.net> wrote in message
>
> news:luhpp3h9vveccutf8...@4ax.com...
>
>
>
> > On Sun, 27 Jan 2008 13:04:39 -0400, "Don White"
> > <whi...@ns.sympatico.ca> wrote:
>
> >>news:479db053....@news.east.earthlink.net...
> >>> On Sun, 27 Jan 2008 09:51:00 -0500, Wayne.B
> >>> <waynebatrecdotbo...@hothail.com> wrote:
>
> >>>>>If the generator shuts down ok by *removing* the 10 amp fuse that
> >>>>>normally
> >>>>>blows
>
> >>> My Maytag washer and drier have the wiring diagrams pasted to the
> >>> inside of the removable sheet metal access panels. Maytag is no more,
> >>> unfortunately.
>
> >>> Casady
>
> >>Whirlpool still use the Mmaytag name but the appliances aren't what they
> >>used to be... re massive recall last year.
>
> > Maytag is still very much in business. Check <http://www.maytag.com>
> > In addition they own many other brands such as Whirlpool, Amana, etc.
>
> > George
>
> > --
>
> eerrr...i think you have that backwards...Whirlpool bought Maytag.
> I know this because I was one of those affected by the inner door/control
>
> - Show quoted text -
The input fuse is the fuse which protects the whole control
panel...I've determined that from the schematic which was as a
previous poster suggested. The stop sequence activates a number of
relays any one of which could be shorting & blowing the fuse. The
engine is killed from a "fuel solenoid", which I believe connects to
the Carbeuretor and may choke the engine. I found a kohler parts
schematic and it looks like I'll need to replace the whole panel...the
relays are not removable. Thanks for all the help!
Dean
wrote:
>> There is a second fuse, but this goes to the battery charging system
>> and seems to be unaffected by the stopping sequence. ?
>> Thanks in advance.
>
>Fuses have other characteristics than Amps. What type does the owners
>manual recommend?
What other parameter is crucial to the situation?
dean
Robert Bonomi
a) whether it has a lawyer connected in series or parallel. <snicker>
b) "fast blow", "slow blow", "Standard blow".
Dean
>I see where bon...@host122.r-bonomi.com (Robert Bonomi) contributed:
>
>Bob AZ <rwats...@aol.com>
>
>>>>Fuses have other characteristics than Amps. What type does the owners
>>>>manual recommend?
>
>Dean <roame...@firstinter.net>:
>>>What other parameter is crucial to the situation?
>
>RB:
>>a) whether it has a lawyer connected in series or parallel. <snicker>
>>
>>b) "fast blow", "slow blow", "Standard blow".
>
>c) Voltage
>
>Will Sill
>The self-appointed Curmudgeon of Sill Hill
What is the voltage meant to protect. Does a 32V fuse 'fuse'
differently than a 120V?
Just plain "Dusty"
those amps.
HTH,
Dusty
"Dean" <roa...@firstinter.net> wrote in message
news:3o0sp35sn31efrjbk...@4ax.com...
...
Jerry Osage
wrote:
Seems to me that a 12v 10amp fuse will open if the power draw is over
120watts.
P=IE 120watts = 12v * 10amp
And a 120volt 10 amp fuse will open if the power draw exceeds
1200watts.
1200 watts = 120v * 10amp
I don't think that a 10 amp/12 volt fuse will work properly in a 10
amp/120 volt circuit. Well, at least it won't work long.
Actually, it does work properly - it blows.
Jerry O.
Just plain "Dusty"
news:tm4sp3lfsq6uab94l...@4ax.com...
>I see where Dean <roa...@firstinter.net> is one of several unaware
> that fuses must meet more than just amp rating, and asks:
>
>>What is the voltage meant to protect. Does a 32V fuse 'fuse'
>>differently than a 120V?
> Bottom line: the Right fuse for the job cannot be chosen entirely on
> amp rating -- even if Dusty thinks otherwise.
No. You're right. I wasn't thinking about the safety rating...and should
have.
I was merely replying to the notion the OP had that somehow fuzes were
voltage limiting. They're not. They're current limiting. Ten amps is ten
amps, whether you're using 'em in a 12V circuit or 120V circuit. But I
should have included the part about the various voltage and safety rating
issues around that. Good catch on my flub, Will. Thanks!
And what really frosts my buns is that I had a few lines to that effect in
that reply, and deleted them before sending it without thinking through what
I ended up conveying...
L8r all,
Dusty
...
Dean
>I see where Dean <roa...@firstinter.net> is one of several unaware
>that fuses must meet more than just amp rating, and asks:
>
>>What is the voltage meant to protect. Does a 32V fuse 'fuse'
>>differently than a 120V?
>
>From Wikipee:
>===================
>As well as a current rating, fuses also carry a voltage rating
>indicating the maximum circuit voltage in which the fuse can be used.
>For example, glass tube fuses rated 32 volts should never be used in
>line-operated (mains-operated) equipment even if the fuse physically
>can fit the fuseholder. Fuses with ceramic cases have higher voltage
>ratings. Fuses carrying a 250 V rating may be safely used in a 125 V
>circuit, but the reverse is not true as the fuse may not be capable of
>safely interrupting the arc in a circuit of a higher voltage.
>Medium-voltage fuses rated for a few thousand volts are never used on
>low voltage circuits, due to their expense and because they cannot
>properly clear the circuit when operating at very low voltages.
>=====================
>
>In many applications, fuses must be chosen for ac or dc rating - dc
>being harder to interrupt.
>
>Bottom line: the Right fuse for the job cannot be chosen entirely on
>amp rating -- even if Dusty thinks otherwise. Do some research.
>
>Will Sill
>The self-appointed Curmudgeon of Sill Hill
>
I agree but that is a 'safety' concern, not a fusing concern. But,
YOU WIN Will. HIHI
dean
Dean
<jerry...@geemail.com> wrote:
>
>Seems to me that a 12v 10amp fuse will open if the power draw is over
>120watts.
>
> P=IE 120watts = 12v * 10amp
>
>And a 120volt 10 amp fuse will open if the power draw exceeds
>1200watts.
>
>1200 watts = 120v * 10amp
>
>I don't think that a 10 amp/12 volt fuse will work properly in a 10
>amp/120 volt circuit. Well, at least it won't work long.
>
>Actually, it does work properly - it blows.
>
>Jerry O.
Shows how wrong you can be Jer. The power is, generally, not a
factor. A 10A fuse MUST blow if 10+amps are drawn whether at 2 volts
or 20 volts.
dean
john jacob
> I have a gas powered 6.5 KW Kohler generator Model 6.5CZ that blows
> the 10 amp input fuse whenever I shut it down from the engine mounted
> or remote kill switches.
This may not be related. However, I have a 20kw Kohler that kept blowing
fuses for no reason. I found out the improper fuse was installed. A 10
amp high heat ceramic fuse should have been used. The heat given off
from the generator engine would heat up the fuse, and de-rate it. A
ceramic fuse is designed to operate in high ambient temperatures.
I hope this helps.
John
Just plain "Dusty"
...
> No problem: it's very hard to communicate an idea accurately with the
> cyber equivalent of a bumper sticker.
Ain't that the truth!
...
> But allow me to add that the voltage rating (fuses, breakers, relays)
> is more than just a "safety" issue - it is a performance criteria.
> Example: I learned the hard way (wind power experiments) that a 120vdc
> circuit cannot be reliably interrupted with a 120vac breaker.
> Compared to ac, a 120vdc arc can get very long before it winks out,
> usually having enough time to cause damage. Relays have to be
> designed to quench the arc.
Roger that as well! BTDT! Except that I did it with a PV system I was
trying to develop. The inverter was going to invert 120VDC to AC. For
testing I was using just a simple PV cell. The breaker was on the control
panel, so I just moved it onto the J-box on the collector housing (the units
were designed to be "ganged" for more power). Everything was working great!
Then I replaced the 1-sun PV I was using with a 200-sun PV array (with
cooling & all). Went from milliamps to *real* amps at ~125V, and toasted
that breaker in one easy lesson...(:-o)! Although, just a little nit to
pick with your statement, the damage was caused by the DC vs. AC, not the
voltage rating of the device.
However, I did manage to achieve my goal of being able to get a kilowatt for
less than a kilobuck (well, truth-be-told, by extrapolating costs to
anticipated production costs). It was a fun & interesting project.
L8r all,
Dusty
...
Dean
>See my reply to Dusty. And what did I win? Can I cash it at Wally's?
>
>Will Sill
>The self-appointed Curmudgeon of Sill Hill
Next time I get to PA, hopefully in 2 years, I'll spring for the
liquid refreshment (w/i reason. = <$1.00 HIHI)
Robert Bonomi
The answer to that question is "Yes, sort-of". <grin>
The fuse rating must be _at_least_ as high as the peak voltage through the
circuit. This ensures that _when_ the link blows, that the resulting air
gap will be of a size that the maximum voltage in the circuit cannot arc
across the gap that was created.
A 4,000V (to pick a number out of thin air) rated fuse will blow at
approximately the indicated _current_ level even if the voltage is only a
few volts. (using such a fuse in a low-voltage circuit is "silly" for a
number of reasons -- size and cost among them -- but it _will_ provide the
required protection.
sylvan butler
> On Mon, 28 Jan 2008 09:54:46 -0800, Jerry Osage
><jerry...@geemail.com> wrote:
>>I don't think that a 10 amp/12 volt fuse will work properly in a 10
>>amp/120 volt circuit. Well, at least it won't work long.
>>
>>Actually, it does work properly - it blows.
> Shows how wrong you can be Jer. The power is, generally, not a
> factor. A 10A fuse MUST blow if 10+amps are drawn whether at 2 volts
> or 20 volts.
Power is generally not a factor, but voltage is. 2v vs 20v may not be
an issue, but 12v rated fuses are not safe at 120v. Higher voltages can
continue to flow thru the ionized gas remaining when a low-voltage fuse
blows.
sdb
--
What's seen on your screen? http://PcScreenWatch.com
sdbuse1 on mailhost bigfoot.com
GBinNC
>D:
>>Next time I get to PA, hopefully in 2 years, I'll spring for the
>>liquid refreshment (w/i reason. = <$1.00 HIHI)
>You could prolly get Janet & GBinNC to finance the cyanide.
That's called "projection" -- projecting one's feelings onto someone
else.
Just because you've shown you can't disagree with someone without
"hating" them -- and perhaps even wishing them dead -- doesn't mean I
feel that way.
GB in NC
Dean
>
>I was gonna walk away without further comment, but once again brevity
>is sometimes the enemy of clarity. You're right that DC vs AC is one
>of the criteria dictating design features of fuses, breakers & relays
>-- largely because DC arcs tend to keep going, whereas AC goes to zero
>volts twice per cycle. But voltage is ALSO a criteria, higher
>voltages being harder to interrupt.
>
Why would a higher voltage be harder to 'fuse'? An arc? Hell, that
would just add to the fusing action, right? What am I missing?
dean
Dean
>I see where Dean <roa...@firstinter.net> contributed:
>
>Will:
>>>See my reply to Dusty. And what did I win? Can I cash it at Wally's?
>
>D:
>>Next time I get to PA, hopefully in 2 years, I'll spring for the
>>liquid refreshment (w/i reason. = <$1.00 HIHI)
>
>You could prolly get Janet & GBinNC to finance the cyanide.
>
>Will Sill
>The self-appointed Curmudgeon of Sill Hill
Or hemlock!
Dean
I don't hate anyone ('cept mebbe Hi.....hell, not even her, I just
fear her). Anyway, I enjoy a discussion; after all I was a lawyer,
but until someone gets personal, I don't mind the exercise.
Dean
Lone Haranguer
Ever gone into a pharmacy and asked for some ground hemlock? They always
look at you funny and reach for the phone......
LZ
Robert Bonomi
factious answers:
1) "the obvious"
2) "brains"
Seriously, look at a medium-hefty, say 10A, _12_Volt_ glass cartridge fuse.
look carefully at the metal strip inside. Notice the _short_ narrow
section? That is the section where the 'goes away' happens when the fuse
blows. the rest of the strip is, as you can see, _much_ wider. It will
carry a _lot_ more current w/o heating up.
Now, if you're applying, say 250VDC (a fairly typical supply voltage for
simple vacuum tube circuits) when that little piece of metal in the
narrow spot goes 'poof', you get vaporization products providing an
ionized gas path that is a fairly _good_ conductor of electricity.
little different from a 'neon light' sign, or a fluorescent light. *MOST*
of the energy consumption is dissipated as light, not that much as heat.
Hence it will not do much, if any, additional 'melting' of the remaining
metal strip.
And the circuit is _not_ interrupted. OOPS!! <grin>
Bob AZ
> >manual recommend?
>
>
Dean
Blowing time. Allowable current surge. Heat. Mechanical
characteristics such as vibration. Perhaps voltage interupring
capacity that would be important when used with an inductance load.
As others have indicated a schematic would be helpful. Although I have
an Onan in my RV it has been yers since I even looked at the book let
alone examined the schematic or wiring diagram.
Bob AZ
Dean
(Robert Bonomi) wrote:
>
>factious answers:
> 1) "the obvious"
> 2) "brains"
I will ignore the smarmy, uncalled for comment.
>
>
>Seriously, look at a medium-hefty, say 10A, _12_Volt_ glass cartridge fuse.
>look carefully at the metal strip inside. Notice the _short_ narrow
>section? That is the section where the 'goes away' happens when the fuse
>blows. the rest of the strip is, as you can see, _much_ wider. It will
>carry a _lot_ more current w/o heating up.
>
>Now, if you're applying, say 250VDC (a fairly typical supply voltage for
>simple vacuum tube circuits) when that little piece of metal in the
>narrow spot goes 'poof', you get vaporization products providing an
>ionized gas path that is a fairly _good_ conductor of electricity.
>little different from a 'neon light' sign, or a fluorescent light. *MOST*
>of the energy consumption is dissipated as light, not that much as heat.
>
>Hence it will not do much, if any, additional 'melting' of the remaining
>metal strip.
>
>And the circuit is _not_ interrupted. OOPS!! <grin>
OK, when the metal fuses, it melts. It does not vaporize into
'ionized gas', rather is melted and what small amounts is vaporized
deposits on to a colder surface (the glass, e.g.).
I spent 25 years involved (as process engineeering tech, engineer and
manager) in thin film vapor deposition in the semiconductor industry
and personally metallized hundreds of square feet of materials with
thin film gold, aluminum, chromium (does not melt, rather goes
directly from solid to vapor), palladium (a pure bitch to deposit),
copper, platinum and some others. These depositions were accomplished
by thermal melting-boiling of pure metals to e-gun spot vaporizing.
Newer technologies include more controllable techniques.
I do agree with your's and Will's general supposition but I suggest
the practical use of 32V fuse in a 120V circuit will seldom, very
seldom, create further issues.
dean
Dean
>I see where Dean <roa...@firstinter.net> contributed:
>
>>Why would a higher voltage be harder to 'fuse'? An arc? Hell, that
>>would just add to the fusing action, right? What am I missing?
>
>You're missing the fact that high voltages can and do jump a longer
>gap. So even if the short section designed to melt disappears on
>schedule, excessively high voltage will not be fully interrupted.
>IOW, the fuse will not work as intended.
>
>Will Sill
>The self-appointed Curmudgeon of Sill Hill
Examine the 2 remaining ends of the link when it melts. It forms
balls which retards the likelyhood or arcing.
dean
Robert Bonomi
Dean <roame...@firstinter.net> wrote:
>On Wed, 30 Jan 2008 23:43:38 -0000, bon...@host122.r-bonomi.com
>(Robert Bonomi) wrote:
>
>>Seriously, look at a medium-hefty, say 10A, _12_Volt_ glass cartridge fuse.
>>look carefully at the metal strip inside. Notice the _short_ narrow
>>section? That is the section where the 'goes away' happens when the fuse
>>blows. the rest of the strip is, as you can see, _much_ wider. It will
>>carry a _lot_ more current w/o heating up.
>>
>>Now, if you're applying, say 250VDC (a fairly typical supply voltage for
>>simple vacuum tube circuits) when that little piece of metal in the
>>narrow spot goes 'poof', you get vaporization products providing an
>>ionized gas path that is a fairly _good_ conductor of electricity.
>>little different from a 'neon light' sign, or a fluorescent light. *MOST*
>>of the energy consumption is dissipated as light, not that much as heat.
>>
>>Hence it will not do much, if any, additional 'melting' of the remaining
>>metal strip.
>>
>>And the circuit is _not_ interrupted. OOPS!! <grin>
>
>
>OK, when the metal fuses, it melts. It does not vaporize into
>'ionized gas', rather is melted and what small amounts is vaporized
>deposits on to a colder surface (the glass, e.g.).
You're right, and wrong. And you don't read carefully.
As the amperage in the fusible link approaches the rated limit, the temperature
approaches the melting point of the fuse material. As it reaches the melting
point, the link starts to sag, stretching it thinner and smaller. Resulting
in a very rapid, *LARGE* temperature increase. ENOUGH to vaporize a
substantial portion of the 'bottleneck' part. (proof -- _all_ you find in a
blown fuse *is* the vapor deposit in the area of the blow; no 'beads' or
'droplets' of solidified molten metal.)
*AS* the link actually separates, it begins with a microscopic gap, that
rapidly widens. That microscopic gap _is_ jumpable by an arc at working
voltage of the circuit. The "miniature arc welder" generates enough localized
heat to vaporize the rest of the mostly molten fusible link. The _metal_vapor_
molecules present help provide a conductive path between the two remaining
pieces of the fusible link -- said path is considerably lower resistance than
the "unpolluted" environment, which allows the arc to sustain itself over a
longer distance. THE ARC _ITSELF_ ionizes the atmosphere in the cartridge
between the 'points', increasing conductivity, and sustaining a larger arc.
>I do agree with your's and Will's general supposition but I suggest
>the practical use of 32V fuse in a 120V circuit will seldom, very
>seldom, create further issues.
Of course, if it _does_ do so, those issues are *catastrophic*.
Feel free to do it for _your_ equipment. I guarantee you won't get UL
or CSA certification. <grin>
For _AC_ circuits, at 'moderate' voltages, I'll not argue hard about your
assessment. (At voltages sufficient for a 'Jacob's Ladder', under-rating the
voltage the device can safely handle by a circa 3:1 factor is fatal.)
For a DC circuit, on the other hand, I *really* wouldn't want to take the
risk. You never get back to the arc 'start-up' situation.
Dean
>I see where Dean <roa...@firstinter.net> contributed:
>
>>>>Why would a higher voltage be harder to 'fuse'? An arc? Hell, that
>>>>would just add to the fusing action, right? What am I missing?
>
>Will:
>>>You're missing the fact that high voltages can and do jump a longer
>>>gap. So even if the short section designed to melt disappears on
>>>schedule, excessively high voltage will not be fully interrupted.
>>>IOW, the fuse will not work as intended.
>
>D:
>>Examine the 2 remaining ends of the link when it melts. It forms
>>balls which retards the likelyhood or arcing.
>
> ::sigh::
>
>Feel free to examine all the blown fuses you like. Those "balls",
>when they occur, are not a big factor in arc maintenance.
>
>You asked, I told ya what the answer is. If you don't like my
>answer, pick one you like.
>
>As for me, I'll use fuses designed for the application. You probably
>will NOT experience a problem using a 30v fuse at 100v - but if you do
>get a problem it will be because you made the wrong choice.
>
>Will Sill
>The self-appointed Curmudgeon of Sill Hill
And I am man enough to live with the consequences.
Dean
(Robert Bonomi) wrote:
>
>You're right, and wrong. And you don't read carefully.
>
>As the amperage in the fusible link approaches the rated limit, the temperature
>approaches the melting point of the fuse material. As it reaches the melting
>point, the link starts to sag, stretching it thinner and smaller. Resulting
>in a very rapid, *LARGE* temperature increase. ENOUGH to vaporize a
>substantial portion of the 'bottleneck' part. (proof -- _all_ you find in a
>blown fuse *is* the vapor deposit in the area of the blow; no 'beads' or
>'droplets' of solidified molten metal.)
I beg to differ. I just 3 days ago, replaced a fuse that had a droplet
of metal stuck to the glass case. When the metal melts, the surface
tension of the mass pulls it into a ball which retards arc by
definition.
>
>*AS* the link actually separates, it begins with a microscopic gap, that
>rapidly widens. That microscopic gap _is_ jumpable by an arc at working
>voltage of the circuit. The "miniature arc welder" generates enough localized
>heat to vaporize the rest of the mostly molten fusible link. The _metal_vapor_
>molecules present help provide a conductive path between the two remaining
>pieces of the fusible link -- said path is considerably lower resistance than
>the "unpolluted" environment, which allows the arc to sustain itself over a
>longer distance. THE ARC _ITSELF_ ionizes the atmosphere in the cartridge
>between the 'points', increasing conductivity, and sustaining a larger arc.
OK, if you think so but I would love to see a technical paper of some
sorts to back up this tale. I have seen high speed photography of
fusing and don't recall this phenomena. Is the cartridge of a glass
barrel fuse under pressure or vacuum of atmosphere?
>
>>I do agree with your's and Will's general supposition but I suggest
>>the practical use of 32V fuse in a 120V circuit will seldom, very
>>seldom, create further issues.
>
>Of course, if it _does_ do so, those issues are *catastrophic*.
Necessarily? I doubt it.
>
>Feel free to do it for _your_ equipment. I guarantee you won't get UL
>or CSA certification. <grin>
>
>For _AC_ circuits, at 'moderate' voltages, I'll not argue hard about your
>assessment. (At voltages sufficient for a 'Jacob's Ladder', under-rating the
>voltage the device can safely handle by a circa 3:1 factor is fatal.)
>
>For a DC circuit, on the other hand, I *really* wouldn't want to take the
>risk. You never get back to the arc 'start-up' situation.
In any event, we are arguing over nits IMHO and further discussion
isn't worth the effort.
dean