220 volts/230 volts/ 240 volts: What's the diff?

[Spencer]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

TWINKLE_TOES,

Wow, thanks for all the research. I'm glad I am not the only one who doesn't quite like the way Miller has engineered this spot welder. I hate to put you out any further but I sure am curious what the Miller engineer would have to say to you.

Thanks Again

 

[TWINKLE_TOES]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

No problem, this is a curious dilemma. I suspect in the begining the manual suggested a 20Amp breaker and the 6-20P plug was fitted to the spot welder to match. After compliants of breaker trips they changed the manual to 30Amps and never revisited the spot welder wiring and plug. Overall I think Miller builds pretty good stuff. I'll let you know what the engineer has to say.

 

[EdDekker]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

Also look at NEC Section 240-3 My understanding is that this section modifies the ampicity requirements (from Table 310-16).

Section 240-3 has a list of 12 conditions which modify the ampacity rules. The tenth rule covers electric welders.

 

[Green_in_MI]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

I cannot address your compatibility problems with 110/120 but I am sure I read somewhere along the line that the power industry has been raising the voltage in incremental steps every few years. It is more efficient to supply power at higher voltages. Low voltage will burn out your motors and I suppose higher voltage may do the same. If you have some power tools that are rated 110 and subject them to a constant 120v source what will happen?

 

[Inspector507]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

dekker,
You're right. Also in the beginning of Art. 210, it says 630 amends the rules in 210. 630 says that the overcurrent device for the conductors supplying the welder can be set or rated at 200%. So, I guess a 30 amp breaker, #10 wire on a 20 amp outlet is okay for welders. Thats for arc welders, for resistance welders it's 300%.

 

[Phred]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

Spencer,

I am not an electrician but an electrical engineer.
I would not worry about it for the following reasons.
1) The current ratings in the NEC code are designed for long runs. This is due to the fact that resistance is proptional to the diameter of the wire as well as the length.
So running wire 50 feet is a different animal than running a short length of wire.
2) The military has long had a set of specifications for building electronic systems. These standards are pretty picky since people's lifes depend upon them. More than 10 amps of current is allowed through tinny little 0.01" diameter aluminum wires in power electronic assemblies. These wires are realively thin compared to a 14 gauge wire and they are made of aluminum which is not as good of a conductor. It works well because the wires are very short.
Many of these assemblies use a large number of these wires to handle very large current levels in small modules, in some cases 100+ amps.

So what I would do if it was mine would be to use the 10 gauge wire and the approved breaker as the instructions call for. As mentioned its a really bad idea to put a outlet on a breaker for which its not rated. For example a 15 or 20 amp outlet on a 30 amp breaker. The outlet might fail.
So make sure your wiring, from outlet to breaker is good for 30 amps.
Plug it in and be happy.

If it really worries you run it for a while and then check the cord for heat. I bet you will find it runs cool.

My two cents.

Fred

 

[Phred]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

Spencer,

Another thought.....

If you look at the power cord it will tell you the NEMA number, I think you mentioned it above. Take this number to any electrical supply house and they can look up the mate. Most of the good supply houses keep a good stock of these outlets.

Fred

 

[TWINKLE_TOES]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

Spencer, I talked with a nice fellow at Miller named Mike(920-831-48980).
I think Inspector507 and Dekker did a fine job of addressing the 30amp breaker and the 6-20R receptacle /forums/images/graemlins/smile.gif. At 2.5kVA and an average current of 11.36 Amps they sorta fit the 300% (30Amp) capacity allowance for spot welders. I guess this is Ok but I sure wouldn't run the spot welder on an extension cord.

Mike identified the following: The high current demand happens on initial contact of the tongs. The maximum current will occur with the shorter tong and the thicker material (3/16"). The thicker the material the longer the duration of this high current condition. Under the short tong and thick material condition a 20A breaker will pop. If your application uses thinner material and longer tongs you may be just fine with the 20Amp outlet. At any rate the 20Amp breaker "overprotects" the welder. Good luck

 

[Spencer]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

TWINKLE_TOES, Thanks for following up on this. I did receive the welder today but the tongs are being shipped separetely. I will be using the longer tongs, the 18" offset ones, most of the time. This will usually be on two pieces of 18 gauge stainless. I think I will go ahead and get a 30 amp breaker and wire that into a 6-20r recepticle. The only other option that I see would be to replace the factory cords and plug but that would probably void my warranty. Miller must know what they are doing.

 

[OkieG]

Re: 220 volts/230 volts/ 240 volts: What\'s the diff?

Do you know a good resource for how to build a small phase converter? I have a 2hp single phase cont. duty motor to power it.

OkieG