There is so much to learn and I have studied so much but still feel this question should be one I could find in the manual but can not. With the AirForce 400 can I run that off of an 50 amp plug in that I use for my handler 175 if I change the plug on the AirForce 400. What I am trying to do is increase the duty cycle and not over-heat the machine. By the way I enjoy reading other people's questions and appreciate all of you comments. Please do not hesitate to elaborate.
Sincerely,
kcoon
KCOON,
By increasing the size of the input fuse you do not increase the duty cycle of your plasma cutter. Follow the recommended fuse size listed in the manual. To increase the duty cycle of the plasma cutter you can figure it out by doing the following: Take the rated output power and multiply by the square root of the rated duty cycle. This gives the 100% duty cycle power rating (unofficial). Now divide this number by the rated output voltage to get the 100% current level. Example – Spectrum 2050, rated output is 55A at 110 at 60%. 100% power level is now calculated to be 110V x 55A x (sqrt 0.6) = 4686W. Now divide back out the voltage 4686W / 110V = 42A. This machine should be able to run at 100% at this power level. This is an approximation so I would dial down 5 amps just to be sure and run it at 35A at 100% duty cycle. Hope this helps. DanV
DanV:
Thank you for the break down on how to calculate the duty cycle. This brings the question: is there any advantage to using the 220volt plug with the AirForce 400?
KCOON,
The advantage is the cost. To use this machine at it’s full potential of 27 amps dc on a 120VAC line you must install a dedicated 30 amp circuit. This means the wire must be sized accordingly, a 30-amp receptacle, and a 30-amp 120-volt plug purchased. These are not cheap. Although the machine has terrific line voltage compensation I personally prefer to operate on a 220 VAC line. And if you already have a 220VAC service to operate your welder I’d just install a 20-amp breaker and go 220VAC. Have fun. DanV
I'm not familiar with the Airforce 400, but just about any welder or motor that is runing on a 120 volt circuit will perform better on 220. The same holds true for 3 phase. The amperage is spread out over more wires or legs. A motor runing on 220 that can be rewired for 3 phase, can run more efficiently(draw less current), on a smaller wire,and thus a smaller breaker can be used too. It seems alot of the welders can voltage sense what power source that are receiving. If the 50 amp circuit you have the 175 plugged into is fed with a #6 wire you can change the plug on the Airforce 400 and plug it in>Providing the Airforce can sense the voltage internally. Motors have to be re-wired internally to change voltage settings. Maybe Dan or Rock knows more about your machine as far as voltage sensing. You don't necessarily have to change the breaker. The breaker is protection for overheating of the wire coming from the panel. The voltage supplied at the outlet is 220. The size of the breaker in your panel has no effect on your Airforce operations, unless the wire is so long that voltage loss is a problem. If your Airforce 400 say it needs a 30 amp 220 volt circuit, the 50 amp circuit will work it will just run cooler. When the welder or cutter is running wide open to the max it probably won't pull 30 amps on the 50 amp circuit. The breaker in the house panel is not a voltage regulator. It is for overcurrent(overheating) protection of the wiring feeding the receptacle. Maybe this will help. Be careful when working on the wiring!
KCOONEY..............OK I'M GOING WITH DANV......... HE WORKS IN PLASMA AND I ASKED HIM TO ANSWER THIS QUESTION....... ECHO8287........ I ALWAYS LIKE TO MATCH THE RATED AMP DRAW TO THE RECEPTICLE.......... I KNOW A 30 AMP DRAW WILL RUN ON A 50 AMP CIRCUIT.............. HOWEVER THINKING SAFETY HERE I MATCH BREAKER'S TO AMPERAGE DRAW.............. 27 AMP DRAW =30AMP BREAKER TO ME............... OLD SCHOOL.......OLD NAVY GUY........ ROCK...............
SSCOTT@MILLERWELDS.COM
Originally posted by DanV KCOON,
The advantage is the cost. To use this machine at it’s full potential of 27 amps dc on a 120VAC line you must install a dedicated 30 amp circuit. This means the wire must be sized accordingly, a 30-amp receptacle, and a 30-amp 120-volt plug purchased. These are not cheap. Although the machine has terrific line voltage compensation I personally prefer to operate on a 220 VAC line. And if you already have a 220VAC service to operate your welder I’d just install a 20-amp breaker and go 220VAC. Have fun. DanV
Dave,here is a major advantage in full output 120 volt use.When using a welding generator,and a little emglo type 120 volt compressor with the plasma you are not overloading one leg of generator when using both together.If you used the plasma on 230 volts,when the air compressor kicked on it would put the plasma into fault mode.I used that setup with my 305g Lincoln engine drive,and a Thermal pakmaster 38xl on 120 volt operation.That is a great use of the 120 volt full output plasma cutting.
Originally posted by Hobart Expert Dave DanV I have not seen duty cycle figured as you have done but it seems to work. I have always learned to do it this way.
Rated Load x Rated load
_____________________ x Duty cycle
Acutual load x Acutual load
Example: Spectrum 2050
55amp x 55amps = 3025
--------------------------------- x 60 =102% duty cycle
42amps x 42amps=1764
Let me know how this works for you?
Thanks
Dave Evans
Dave, I received my info from one of my engineers. You say Tomato.....I say Tomaato....either one... Both seem to work. DanV
Gee,, here I would have just guessed at 40A or so and saved the pencil lead,,, hahaha,,, but the main advantage as Echo pointed out was with the building wiring itself when going with higher voltages. You need dedicated circuit for this machine anyway so why not benifit from hi voltage. I run wire for each machine so I dont have to green acres them and can tailor the breaker to each one. I am not sure about plasma in general or this unit in particular and I just assume with electronic units that it probably you probably wont ever need to increase the overcurrent protection deleberately they way you may have to with transformer type machines. You are allowed to increase breaker size on same wire if it trips but I would think that it might be against the rules to change the plug itself. (personally guilty of doing that on machines) There is actually a provision in NEC for welding machines that includes overcurrent protection allowances for welders.
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