Sizing Conductors & Breaker for Arc welder

I

IanO3

Member
Location
Florida
Occupation
Electrician
The nameplate of a Syncrowave 350LX Arc welder (Cant figure out how to attach photo) does not specify an Effective (eff) or a Max current value. So I'm of the assumption (😬) That the Current value given on the nameplate (i1) is the primary rated current at its given voltage.

It will be wired 240V (230v) and shows an i1 of 131.1A.
Its my understanding that duty cycles can be adjusted by the the person welding when adjusting the output amperage, And the nameplate represents this showing multiple duty cycle percentages at different output currents (i.e. 30% @ 400A, 40% @350A ... , 100% @ 250A).

The question is how to determine the duty cycle to use in Table 630.11(A) when given primary rated current, and adjustable duty cycles.

Questions solve ignorance.
Thanks in advance,
- Ian
 
infinity said:
Did you take a glance at the owners manual? It has some specifications:

View attachment 2575299
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Yes, I currently have that document (2-9 electrical service guide) and (2-3 specifications) page printed out. I didn't just go with this, as my initial concern was that #4AWG seems incorrect for a 112A input rating. That concern is why I opened Art. 630 to try and size everything myself off the nameplate.

If the "With Power Factor Correction" table was to be used than why provide the first table "Without .. Correction"?
I was also concerned with the "Note" at the top letting me know they are calculated at 60% duty cycle, as if to say "If not being used at 60% duty cycle this would be irrelevant."

I'm sure I'm misunderstanding or overthinking this.
Any help is appreciated.
 
IanO3 said:
The question is how to determine the duty cycle to use in Table 630.11(A)
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You'll have to ask the customer about that, that is whether they plan to use the machine full-tilt all the time or occasionally at half the capacity.

BTW, I haven't checked and it probably hasn't changed, but the quoted table references the 1996 code and it's pretty likely that Florida is using a newer one.
 
zbang said:
You'll have to ask the customer about that, that is whether they plan to use the machine full-tilt all the time or occasionally at half the capacity.

BTW, I haven't checked and it probably hasn't changed, but the quoted table references the 1996 code and it's pretty likely that Florida is using a newer one.
Click to expand...
I noticed that as well, and checked a 1996 NEC ampacity table to ensure it hadn't changed.

As for asking the customer, I don't like the idea of something being sized based on someones promise of how they'll use it. I feel it should be sized based on the largest possible amperage especially since its as simple as the turn of a dial for output amperage?

If a welder is capable of a 100% duty cycle (Adjustable) do you just size directly from the Rated Primary Current (1.00 Multiplier)?
I'm aware if I do that it takes away any fears I would have, but would like to know the proper procedure.
 
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