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Len
 
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Default Varistor to shield voltage spikes

Hi group,

I want to use a welding machine on board and power it with my onboard
6 kW generator. The welding machine is a AC/DC HF-TIG with a lot of
electronics inside. I have no documentation of my generator so I
wanted to deal with the possibility of voltage spikes fi directly
after stopping the welding-arc.

My ships chandler gave me the following advice:
In the power cord add an automatic fuse. Directlly after the fuse
connect the phase and the null using a 235v Varistor. Under 235 volts
it'll maintain high resistance and all will function normally. When
the voltage exceeds 235 it will short circuit and the fuse will break
the connection.

What do you think of this setup. Will it operate fast enough to really
prevent a voltage spike to reach my welding machine?

Regards, Len,
S/v Present
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Larry
 
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Default Varistor to shield voltage spikes

Silly me....I'd just disconnect the boat from the genset while I was
using the welder. Switch off the boat's breaker and run the welder
directly from an outlet on the genset, even if you have to add it.

KISS....(c;



Len wrote in
:

Hi group,

I want to use a welding machine on board and power it with my onboard
6 kW generator. The welding machine is a AC/DC HF-TIG with a lot of
electronics inside. I have no documentation of my generator so I
wanted to deal with the possibility of voltage spikes fi directly
after stopping the welding-arc.

My ships chandler gave me the following advice:
In the power cord add an automatic fuse. Directlly after the fuse
connect the phase and the null using a 235v Varistor. Under 235 volts
it'll maintain high resistance and all will function normally. When
the voltage exceeds 235 it will short circuit and the fuse will break
the connection.

What do you think of this setup. Will it operate fast enough to really
prevent a voltage spike to reach my welding machine?

Regards, Len,
S/v Present


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posted to rec.boats.electronics
Len
 
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Default Varistor to shield voltage spikes

Hi Larry, thanks for responding, mate.

I do use an outlet directly off the genset.
I wouldn't weld via the ships net... might fry the combined
charger/inverter.

Point is the genset may deliver voltage spikes (according to anyone
here I speak to) when I use it to operate the welder. Particularly
when I stop the welding-arc the genset could give a surge.
I use the varistor/fuse to shut the power off when voltage exceeds
235v but I wonder if this really protects the welder...
I mean when the varistor senses 235 it shortcircuits but that takes
time. In this time only a superb being knows what can happen...or?

Thanks, Len.


On Fri, 13 Jan 2006 08:17:17 -0500, Larry wrote:

Silly me....I'd just disconnect the boat from the genset while I was
using the welder. Switch off the boat's breaker and run the welder
directly from an outlet on the genset, even if you have to add it.

KISS....(c;



Len wrote in
:

Hi group,

I want to use a welding machine on board and power it with my onboard
6 kW generator. The welding machine is a AC/DC HF-TIG with a lot of
electronics inside. I have no documentation of my generator so I
wanted to deal with the possibility of voltage spikes fi directly
after stopping the welding-arc.

My ships chandler gave me the following advice:
In the power cord add an automatic fuse. Directlly after the fuse
connect the phase and the null using a 235v Varistor. Under 235 volts
it'll maintain high resistance and all will function normally. When
the voltage exceeds 235 it will short circuit and the fuse will break
the connection.

What do you think of this setup. Will it operate fast enough to really
prevent a voltage spike to reach my welding machine?

Regards, Len,
S/v Present


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posted to rec.boats.electronics
Larry
 
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Default Varistor to shield voltage spikes

Len wrote in
:

Point is the genset may deliver voltage spikes (according to anyone
here I speak to) when I use it to operate the welder. Particularly


If your welder were hooked to the genset as you say, then simply disconnect
the boat from the genset by turning off the boat's main AC breaker at the
panel until you're done with the welder. No surge makes it through an open
breaker. The boat won't sink if it doesn't have AC power for a couple of
hours while you're welding..(c;

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Len
 
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Default Varistor to shield voltage spikes

On Fri, 13 Jan 2006 19:42:30 -0500, Larry wrote:

If your welder were hooked to the genset as you say, then simply disconnect
the boat from the genset by turning off the boat's main AC breaker at the
panel until you're done with the welder. No surge makes it through an open
breaker. The boat won't sink if it doesn't have AC power for a couple of
hours while you're welding..(c;


Sorry Larry, didn't make myself clear enough.
The boat _is_ shut off... I want to protect the welder's electronics.
The d**ned thing is expensive.

TIA, Len.




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Larry
 
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Default Varistor to shield voltage spikes

Len wrote in
:

Sorry Larry, didn't make myself clear enough.
The boat _is_ shut off... I want to protect the welder's electronics.
The d**ned thing is expensive.



The welder's electronics runs off a regulated power supply that already HAS
circuit protection to keep the welder manufacturer out of the welder repair
business. Welders are lucky if they get 80% of their spec voltage in a car
shop...(c;

Don't think so? Call the manufacturer or send him an email and ask 'em.

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Len
 
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Default Varistor to shield voltage spikes

On Sat, 14 Jan 2006 07:53:29 -0500, Larry wrote:

The welder's electronics runs off a regulated power supply that already HAS
circuit protection to keep the welder manufacturer out of the welder repair
business. Welders are lucky if they get 80% of their spec voltage in a car
shop...(c;

Don't think so? Call the manufacturer or send him an email and ask 'em.


I did. But I guess these pimplefaced youngsters that call themselves
full blown sales-people don't know anything usefull and therefor tend
to avoid any just ANY risk of being accountable.

But what do you think of the varistor/fuse setup? I also want to use
it in the incoming shore connection. Some shore connections are
generator powered. That means there is a risk of the null hanging a
bit loose what may cause v-spikes also. Would this setup protect my
combined inverter charger in your opinion?

CU, Len.

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w_tom
 
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Default Varistor to shield voltage spikes

Len wrote:
But what do you think of the varistor/fuse setup? I also want to use
it in the incoming shore connection. Some shore connections are
generator powered. That means there is a risk of the null hanging a
bit loose what may cause v-spikes also. Would this setup protect my
combined inverter charger in your opinion?


Destructive transients are done in microseconds. Fuses take tens or
hundreds of milliseconds just to consider tripping. Varistor life
expectancy is defined by a parameter called joules. And then you must
define the type of transient - longitudinal or transverse. The most
damning part of your theory is no numbers. With numbers, you have far
more to consider. Properly noted is that electronics already have
internal protection. So your only question means you must first define
how bad that generator really is. Again, get numbers - specifications.
Without first defining what you are protecting from, then no one can
provide anything but wild speculation - Rush Limbaugh type response.

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Len
 
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Default Varistor to shield voltage spikes

On 14 Jan 2006 17:18:24 -0800, "w_tom" wrote:

Len wrote:
But what do you think of the varistor/fuse setup? I also want to use
it in the incoming shore connection. Some shore connections are
generator powered. That means there is a risk of the null hanging a
bit loose what may cause v-spikes also. Would this setup protect my
combined inverter charger in your opinion?


Destructive transients are done in microseconds. Fuses take tens or
hundreds of milliseconds just to consider tripping. Varistor life
expectancy is defined by a parameter called joules. And then you must
define the type of transient - longitudinal or transverse. The most
damning part of your theory is no numbers. With numbers, you have far
more to consider. Properly noted is that electronics already have
internal protection. So your only question means you must first define
how bad that generator really is. Again, get numbers - specifications.
Without first defining what you are protecting from, then no one can
provide anything but wild speculation - Rush Limbaugh type response.


Wow, of course, thats it, get numbers and specs.... Why didn't I think
of that????
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Larry
 
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Default Varistor to shield voltage spikes

Len wrote in
:

I did. But I guess these pimplefaced youngsters that call themselves
full blown sales-people don't know anything usefull and therefor tend
to avoid any just ANY risk of being accountable.



It's called creating an "implied warranty of suitability for a particular
purpose". If you sell can openers and, in your zeal to get the sale,
tell the "consumer" (legal term in the law) that this can opener will
open any can that contains food, you have created an implied warranty of
suitabilitiy for a particular purpose. If the item doesn't perform TO
THE CONSUMER'S SATISFACTION, the consumer can demand replacement or
refund. So, it's best to tell your sales people to keep their big mouths
shut and tell the "consumer" as little about the defective can openers
you sell as possible, making no promises it will open any can at all.

http://www.ftc.gov/bcp/conline/pubs/...s/warranty.htm

Every consumer should read this FTC manual. It explains to the seller
what the implied warranties HE CANNOT JUST DECLINE AWAY on his limited
warranty wallpaper are and what his responsibility to the consumer is.
Great reading if you have a lemon...(c; Unless the manufacturer can talk
the FTC into a waiver, the Magnusson-Moss Warranty Protection Act
(15USC50 section 2300) is in full force. It's even written in English,
for a change, and is very specific, no matter what bull**** the
dealer/store says.

http://www.law.cornell.edu/uscode/ht..._15_10_50.html

The part that worked for me is:
http://www.law.cornell.edu/uscode/ht...5_00002304----
000-.html

Little paragraph a4 reads, interestingly enough:
"(4) if the product (or a component part thereof) contains a defect or
malfunction after a reasonable number of attempts by the warrantor to
remedy defects or malfunctions in such product, such warrantor must
permit the consumer to elect either a refund for, or replacement without
charge of, such product or part (as the case may be). The Commission may
by rule specify for purposes of this paragraph, what constitutes a
reasonable number of attempts to remedy particular kinds of defects or
malfunctions under different circumstances. If the warrantor replaces a
component part of a consumer product, such replacement shall include
installing the part in the product without charge."

Notice it says "MUST PERMIT THE CONSUMER TO ELECT", not the dealer or the
manufacturer's weasles. I think it could easily be used on those
defective boats you're all buying they tell you they can't or won't fix.

The judges tell them 3 attempts or 30 days....all the time.

The manufacturers have a buzzword to explain it all away. They call it
"buyer's remorse", placing all the blame on the buyers.

My attorney disagreed....(c;

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