PM45XP- Thickness capability at 100% duty cycle?

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Bobkovacs
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PM45XP- Thickness capability at 100% duty cycle?

Post by Bobkovacs » Wed Jan 18, 2017 8:24 am

In looking at the literature for the new 45XP, they list the duty cycle at 45A as 50%, and at 31A at 100%, yet all of the cutting charts show 45A as the recommended setting. From what I've heard, you want to use the 100% duty cycle rating to determine what thickness you can typically cut on a CNC table- if that's the case, what's the recommended max thickness for this machine in a CNC environment? Anyone have any first-hand experience with it yet?

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Re: PM45XP- Thickness capability at 100% duty cycle?

Post by jimcolt » Thu Jan 19, 2017 10:18 am

If we included every cutting thickness / amperage possibility then there would be thousands of pages of cut charts. We have received complaints over the years that our operators manuals are already too big....with too much info, however we get more compliments regarding the info in our manuals than complaints.

Duty cycle is easy to figure out in a laboratory. The factors are that dramatically affect duty cycles are output amperage, output voltage (length of the arc) and ambient temperature (room temperature). Our dut cycle rating on the Powermax 45 XP, like it is with all of our systems....is when cutting the rated production thickness on a 104 degree F. (40 C) day. So the Powermax45 XP is rated to production cut 5/8" steel at 50% duty cycle on a 104 degree day using 45 amps at 146 arc volts (torch height of .06" + 5/8" plate thickness determines the load voltage or arc voltage) which means the power supply is producing 6525 watts.

If you are cutting on a 70 degree day...that duty cycle rating would be higher....probably in the 70% range on the same 5/8" steel. If you cut thinner than 5/8".....the duty cycle would go even higher....while at 45 amps. If you decide to turn the amperage down to 30 amps.....you can sever that same 5/8" steel (slower speed, more dross) and the duty cycle would be higher. So amperage affects duty cycle, ambient temperature affects duty cycle and material thickness affects duty cycle.

Then there is the design of the torch consumables....some consumables produce much more energy density in Amps per square inch. If you look at the Fine cut charts for 10 gauge steel...then you will see it cuts at 45 amps and 78 volts while the 45 amp shielded consumables will cut at the same 45 amps but at 128 volts. The Finecut consumables use less power (3,510 watts) to cut 10 gauge while the 45 Amps shielded consumables use 5760 watts to cut 10 gauge. On a 104 degree day the power supply is conservatively rated at 6525 watts at 50% duty cycle, and 4,640 watts at 100% duty cycle.
Duty cycle is only counted when the plasma arc is on. I have been working with CNC cutting machines and the owners for 40 years....in a production environment it is very difficult to exceed 35% or 40% on time.....due to traverse time between cuts as well as a ton of other factors.

So...to best answer the question from Bobkovacs regarding max thickness at 100% duty cycle I would need some data (ambient temp) and a math wizard and an electronics engineer. Since I have a bit of experience I would suggest using the Finecut consumables to cut 1/4" steel on a 104 degree day with a Powermax45 XP and you will achieve 100% duty cycle. The Finecut consumables can cut 1/4", not as nicely or with as long life as the 45 amp shielded consumables....however they are efficient and use less power if 100% duty cycle is needed.

First...you will only achieve 100% duty cycle by cutting with one start and not stopping all day. After an hour or two you will need to change consumables, so this will reduce duty cycle. The earlier Powermax45 had a bit lower duty cycle rating of about 5900 watts on a 104 degree F day. On 1/2" steel and less I have never heard of one exceeding duty cycle unless there was something wrong (fan failed, louvers blocked, internally full of shop dust, etc. One last thing....I happen to know that the duty cycle ratings of all Powermax units are conservative. The engineering heat rise testing that is done in our labs operates at a certain percentage of higher wattage (than our advertised rating) and at a higher than 104 degree rating. If you are worried about duty cycle step up the the Powermax65, 85, 105 or the 100% duty cycle Powermax125! We have tested many, many competitive plasma cutters under the same conditions in the same labs.....most manufacturers duty cycles are highly incorrect. The Chinese imports are the worst offenders with high duty cycle numbers.....but actual results that are a fraction of the advertised values!

Jim Colt Hypertherrm

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lockeyone
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Re: PM45XP- Thickness capability at 100% duty cycle?

Post by lockeyone » Thu Jan 19, 2017 5:15 pm

Sounds like you could make up an online calculator to help get that starting point? Just a thought.

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Re: PM45XP- Thickness capability at 100% duty cycle?

Post by jimcolt » Fri Jan 20, 2017 7:46 am

The cut charts in the manual are developed by cutting a lot of material. They are probably the best starting points you will find. In regards to duty cycle....if you need 100% duty cycle....then you should get a plasma cutter that is rated for 100%. All of the industrial plasma cutters in the Hypertherm product line above 130 amps are 100% duty cycle. They are large, with liquid cooled torches and they cost a lot more than the Powermax air plasma systems. The Powermax air plasma cutters are designed to be portable, lightweight and affordable compared to the industrial units....to achieve that they are lower in output power / duty cycle. Jim Colt Hypertherm

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Re: PM45XP- Thickness capability at 100% duty cycle?

Post by namlecnc » Sun May 24, 2020 1:02 am

So would 45xp be fine cutting 1/2” for 12-15minutes straight?

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Re: PM45XP- Thickness capability at 100% duty cycle?

Post by sonbakler » Sun May 24, 2020 9:34 pm

namlecnc wrote:
Sun May 24, 2020 1:02 am
So would 45xp be fine cutting 1/2” for 12-15minutes straight?
No, I am sure it will shut you down to cool off for a little while. If your cutting 1/2" all the time your really working the hell out of the little guy.

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Re: PM45XP- Thickness capability at 100% duty cycle?

Post by adbuch » Mon May 25, 2020 1:22 am

namlecnc wrote:
Sun May 24, 2020 1:02 am
So would 45xp be fine cutting 1/2” for 12-15minutes straight?
The 45xp is rated for 50% duty cycle at 45 amps 40 degree C ambient temperature. You could probably cut for 30 seconds to a minute, then wait for 30 seconds to a minute, and repeat the process. So the answer to your question is "NO".
David
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Re: PM45XP- Thickness capability at 100% duty cycle?

Post by jimcolt » Mon May 25, 2020 1:04 pm

1. The Powermax45xp is rated for 50% duty cycle when cutting 5/8" steel on a 104 F (ambient temperature day). To determine the wattage output of the power supply when cutting 5/8" steel multiply the arc voltage listed in the cut chart for 5/8" steel x the cutting amperage. Without a manual in front of me I believe the cutting voltage is around 140 volts, so the wattage on 5/8" steel is 140 volts x 45 amps = 6,300 watts of cutting power. The 45xp when producing 4500 watts on a 104 F day is 50% duty cycle. That rating assumes that the core temperature of the 45XP power supply is at its operating temp (has been running and cutting thick materials) So....50% duty cycle on 5/8" steel (with core temp normal) means you can be expected to cut for 5 minutes continuous, then 5 minutes rest, then repeat all day if you desire. On 5/8".
2. If you are cutting 1/2" steel you will find that the cutting voltage is lower than for 5/8". (again no manual handy). So I am guessing that the cut voltage for 1/2" is around 132 volts, so 132 x 45 = 5940 watts is about 6% lower wattage....so the duty cycle may be 6% higher when cutting 1/2" steel on a 104C day....meaning you could cut longer and rest less without tripping the internal duty cycle protection.
3. I'm going to guess that somewhere between 1/4" and 3/8" will allow you 100% duty cycle with the 45xp on a 104 degree F day.
4. So cut and rest, or cut til the plasma shuts down (it will not let itself melt!). Better yet, if you have to cut 1/2" on a 104 degree day, maybe you need to step up to a Powermax65 or 85.
5. If someone tells me they need to be highly productive (meaning very little arc off time) and need to cut 1/2" all day long on a cnc machine when it is really hot in the shop....then I would suggest a Powermax85 (if they only had single phase power) or better yet a Powermax105....even better a 125 if they had 3 phase power. On top of these are the larger oxygen based systems like the MaxPro200 and the XPR series high definition class machines....which are 100% duty cycle (the 125 is as well) Jim Colt

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Re: PM45XP- Thickness capability at 100% duty cycle?

Post by adbuch » Mon May 25, 2020 5:20 pm

Jim - thanks for the information and advise!
David

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