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Ambient Operating Temps

Hypertherm Plasma Cutter discussion forum.
rbmgf7
Posts: 61
Joined: Sat Apr 01, 2017 5:38 pm

Ambient Operating Temps

Postby rbmgf7 » Sat Apr 21, 2018 5:03 pm

I picked up a job last fall where I cut a lot of 1/4" on a 3 week cycle. The parts are small and only take about 30 sec to cut but I burn anywhere from 2 to 5 4x8 sheets in a day or two. Machine is a PM45 at 45A.

When it was cooler (~40F) in the fall, I could get 1 to 1.5 parts before the fan kicked on. The fan would cycle for about 20 seconds and then repeat the cycle.

Now that it's starting to warm up outside, I'm doing the same job but the fan runs continuously. The ambient temp is high 60s low 70s. Even when I start the machine for the first time in the day, the fan comes on after about 10 seconds of cutting and runs non-stop.

Is this normal or is something up? I haven't done any heavy cutting in warmer weather. I've never opened the box since everything has been good these couple years. There was some dust/dirt on the intake louvers so I would assume some made it's way inside and maybe affecting the heatsinks?

SegoMan DeSigns
Posts: 65
Joined: Sat Jan 06, 2018 4:45 pm

Re: Ambient Operating Temps

Postby SegoMan DeSigns » Sat Apr 21, 2018 5:10 pm

When was the last time you assassinated the dust bunnies inside the machine? I try to do mine every 6 months or so, pull the cover and use compressed air to clean it our. The manual has some other maintenance routines to follow as well.

rbmgf7
Posts: 61
Joined: Sat Apr 01, 2017 5:38 pm

Re: Ambient Operating Temps

Postby rbmgf7 » Sat Apr 21, 2018 6:27 pm

Cleaned it out. Small cloud puffed out the front and back. Blew out everything but for the most part seemed pretty clean.

Put it back together and the fan still runs continuously. I've never ran it this hard so not sure what to think. Upgrading to a 65 would be nice but gotta work with what I have.

SegoMan DeSigns
Posts: 65
Joined: Sat Jan 06, 2018 4:45 pm

Re: Ambient Operating Temps

Postby SegoMan DeSigns » Sat Apr 21, 2018 6:36 pm

My 65 runs quite a bit on 1/4" and up as well just not continuously unless it's a long 1/2" job maybe Jim Colt will drop in with some of his wisdom .

rbmgf7
Posts: 61
Joined: Sat Apr 01, 2017 5:38 pm

Re: Ambient Operating Temps

Postby rbmgf7 » Sat Apr 21, 2018 8:36 pm

I placed a box fan next the the air intake and set it on a medium speed. I could get the PM to stop the internal fan every couple parts but just for 10 or so seconds. The ambient temp did go down to low 60's too.

rbmgf7
Posts: 61
Joined: Sat Apr 01, 2017 5:38 pm

Re: Ambient Operating Temps

Postby rbmgf7 » Sun Apr 22, 2018 9:57 am

I did a deep search and found one post by Jim claiming how their duty cycles are tested in an ambient setting of 104F.

So, considering it was 70F and I was cutting at 45A but the machine never thermally tripped, I was probably working at a reasonable DC above the 50%.

Then my cooler situation from at 40F was probably offering me a much higher DC than 70F.

Makes me wonder why anyone hasn't made a water cooler for these units? Any mad scientists out there? lol

yroc fab
Posts: 20
Joined: Mon May 16, 2016 3:56 am

Re: Ambient Operating Temps

Postby yroc fab » Mon Apr 23, 2018 6:43 am

rbmgf7 wrote:I did a deep search and found one post by Jim claiming how their duty cycles are tested in an ambient setting of 104F.

So, considering it was 70F and I was cutting at 45A but the machine never thermally tripped, I was probably working at a reasonable DC above the 50%.

Then my cooler situation from at 40F was probably offering me a much higher DC than 70F.

Makes me wonder why anyone hasn't made a water cooler for these units? Any mad scientists out there? lol


Water cooled.. . I have wondered why they don't make them air cooled, as in use the compressed air already passing through the machine. Why not have it pass through an inter-cooler with a fan on the back side of it.

jimcolt
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Re: Ambient Operating Temps

Postby jimcolt » Mon Apr 23, 2018 12:27 pm

It is normal for the fan to run continuously at normal inside room temps when cutting a lot. All Hypertherm unit duty cycle ratings are based on on cutting the production thickness rating (of each system) on a 104 F day (40C). The newest Powermax45XP is production rated for 5/8" thick steel (45 amps output at 145 VDC, 6525 watts) with a 50% rating under these conditions. Things that will make for a longer duty cycle: Lower ambient temp, lower arc voltage (thinner material), lower amperage. When cutting 1/4" steel you will likely have 100% duty cycle as the arc voltage is lower....even on a 104F day. The fan is inside the unit to transfer heat, and it is operated thermostatically. It is designed to shut off when not needed in order to minimize internal dust buildup. If by chance you exceed duty cycle (rare with a Hypertherm) the duty cycle light will illuminate on the front panel, the fan will run, the plasma arc will extinguish.....until internal components have cooled to a safe level.

Why don't we build all of our plasma cutters to be 100% duty cycle? It adds cost and weight and physical size. Air plasma's are in a very competitive market so these things must be taken into account. You can actually buy a bigger unit, like the Powermax65 and keep the amperage knob locked at 45 amps, voila, a 100% duty cycle unit!

The largest Powermax, the Powermax125 is 100% duty cycle. It has no competition and is used for commercial and industrial use almost exclusively. The next larger unit in Hypertherm's product line, the MaxPro 200 is 100% duty cycle and has a liquid cooled torch and a liquid cooled inverter switching circuit (IGBT controlled). All of our systems over 125 amps (we have an HPR130xd, HPR260XD, XPR300XD, HPR400XD and HPR800XD) are liquid cooled torches and 100% duty cycle. Jim Colt Hypertherm

rbmgf7
Posts: 61
Joined: Sat Apr 01, 2017 5:38 pm

Re: Ambient Operating Temps

Postby rbmgf7 » Mon May 07, 2018 10:34 am

yroc fab wrote:
rbmgf7 wrote:I did a deep search and found one post by Jim claiming how their duty cycles are tested in an ambient setting of 104F.

So, considering it was 70F and I was cutting at 45A but the machine never thermally tripped, I was probably working at a reasonable DC above the 50%.

Then my cooler situation from at 40F was probably offering me a much higher DC than 70F.

Makes me wonder why anyone hasn't made a water cooler for these units? Any mad scientists out there? lol


Water cooled.. . I have wondered why they don't make them air cooled, as in use the compressed air already passing through the machine. Why not have it pass through an inter-cooler with a fan on the back side of it.


Then you would need more CFM and filtered/dry air. I would hate for people to plumb unfiltered air into their box just to have it gum up with compressor oil and moisture.

But, it would operate cooler since compressed air that's released to atmospheric is cooler.

jimcolt
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Re: Ambient Operating Temps

Postby jimcolt » Wed May 09, 2018 8:26 am

Compressors are very inefficient....so cooling with compressed air (using the pressure drop for a refrigerant effect) would work really well, however would be inefficient. We can make any plasma cutter 100% duty cycle. It will be heavier, larger, and will cost more. That is why most air plasma cutters (of which over 90% of units worldwide are used for hand cutting) have duty cycles in the 40 to 60% range. I have yet to see a hand torch operator exceed more than about 30% duty cycle, assuming they are cutting material within the design thickness range of the plasma cutter being used. Yes.....if you have a 30 amp plasma rated for production use at 1/4".....and decide to cut 1/2"....then expect to exceed the duty cycle. Jim Colt Hypertherm

rbmgf7
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Joined: Sat Apr 01, 2017 5:38 pm

Re: Ambient Operating Temps

Postby rbmgf7 » Wed Jun 06, 2018 12:47 pm

Since I'm fortunate to live in a split level with the basement underground and climate controlled, I ran a flex duct from the plasma, into the basement and then hooked up a 400cfm blower fan to feed cool, dry air to the unit.

Seems to keep the 45 happy and cool on my full sheet cuts at 45A.

Then when I'm doing other work, I can unhook the flange and cool myself.

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jimcolt
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Re: Ambient Operating Temps

Postby jimcolt » Mon Jun 11, 2018 2:47 pm

There is no good reason that I can think of to do this. The Hypertherm units are very conservatively rated for duty cycle, and they are rated for 104 degrees F (40C) ambient. The cooling system is thermostatically controlled which limits the dirty air through the machine. If anything, cool air from your basement may cause condensation issues inside the Powermax unit. Jim Colt Hypertherm

rbmgf7
Posts: 61
Joined: Sat Apr 01, 2017 5:38 pm

Re: Ambient Operating Temps

Postby rbmgf7 » Tue Jun 12, 2018 1:02 am

The basement is climate controlled through the homes HVAC so cycling air through the handler removes moisture from the contained atmosphere from within the house, supplying relatively dry air to the unit. The air is definitely cleaner in the basement than it is in the garage.

It cut for nearly 8 straight hours for 2 days without issues when it was 90 degrees outside with 80% humidity (welcome to Missouri). No condensation whatsoever. With moving air, it's harder to condensate anyways. I only intend to use the forced-air setup for my long, continuous cuts. However, if I don't use the force air during my long cuts, then the fan runs continuously, therefore, sucking in the dirty air.


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