new to me hypertherm 900

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cdedwards
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new to me hypertherm 900

Post by cdedwards » Fri Jul 31, 2020 7:39 pm

I purchased at an auction a highly used 800 and 900 hypertherm. The 800 was described as non-working and when I took it in to have it looked at, I was told that parts are no longer available. it's broke. leaving me the 900 which does work. However without a torch, and with hypertherm quitting manufacturing of consumables, I was left in a quandry. I eventuallty found a company on ebay, plasmadybusa who happen to have had a machine torch for sale. So far so good.

My question is, can I add a CPC port to the 900 as an aftermarket feature. ideally with 50:1 voltage divider? Or do I need to wrap a lead around a magentic reed switch giving me a poor man's ArcOK signal. I'm competent enough that I switched the 900 from a 3-phase source over to single phase and do all my own wiring including the electronics for the DIY plasma table I'm building.

Also, does anyone have a cut chart to use with the 900?

adbuch
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Re: new to me hypertherm 900

Post by adbuch » Fri Jul 31, 2020 8:55 pm

Hypertherm offers Duramax retrofit torches for the 900 here.

http://www.hypermaxonline.com/Hyperther ... ables.html
Duramax retrofit machine torch for Powermax 900.jpg
You can purchase machine torch here.

https://www.harrisweldingsupplies.com/h ... x42-max43/
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adbuch
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Re: new to me hypertherm 900

Post by adbuch » Fri Jul 31, 2020 9:13 pm

The manual for the 900 has some cut charts, but they are for the 900 consumables.
Hypertherm Powermax 900 manual.zip
If you upgrade to the Duramax torch, then I would think a good starting place would be the Hypertherm 65/85 mechanized cut charts.
David
Powermax65 85 Operator Manual (806650 revision 4).zip

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adbuch
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Re: new to me hypertherm 900

Post by adbuch » Fri Jul 31, 2020 9:22 pm

I do not believe there is a CPC port upgrade for the 900. With your electrical/electronic experience, it should be fairly simple for you to make up a voltage divider and wire it up to monitor your arc voltage. For true THC you would want to monitor the actual (divided) arc voltage, and not simply detect on/off "arc-OK". Let me know if you need more information about wiring in your voltage divider.
David

Rodw
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Re: new to me hypertherm 900

Post by Rodw » Fri Jul 31, 2020 9:54 pm

If you were comfortable running Linuxcnc, a $69 Mesa THCAD board would solve your lack of divided arc voltage. Add to that a $119 Mesa 7i96 board and you would have all your THC and motion control problems sorted. I'd need to know if you have a HF start or a blow back start torch to pick the THCAD version for you.

From all accounts, the reed switch works quite well. I did make up an alternate design which was a toroid ring around the work clamp that had a slot cut in and a hall effect sensor placed in the gap. I never ended up using it.

The Linuxcnc Plasmac config has photos and circuit diagrams of the reed relay under heading 30.4 http://linuxcnc.org/docs/2.8/html/plasm ... guide.html

The Plasma primer is also a useful resource.
http://linuxcnc.org/docs/2.8/html/plasm ... rimer.html

The good news is that I think the long overdue release of Linuxcnc V 2.8 containing Plasmac is slated for this weekend so in a few days, you should just need to install Linuxcnc from an ISO and have Plasmac.

Rodw
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Re: new to me hypertherm 900

Post by Rodw » Fri Jul 31, 2020 9:57 pm

I forgot to mention that PLasmac can synthesise an Arc OK signal but some have issues with this so the reed switch is abetter solution.

cdedwards
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Re: new to me hypertherm 900

Post by cdedwards » Sun Aug 02, 2020 12:42 pm

my plan is to use linuxcnc and am currently setting it up to run the table. Just need to get the plasma power supply sorted out. I already have a both a THCAD-300 and proma giving me options. Everything I've read about the hypertherm 900 says it has pilot-arc. Thanks for eveyone's input here, I'm sure I'll have more questions.

Rodw
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Re: new to me hypertherm 900

Post by Rodw » Sun Aug 02, 2020 4:41 pm

Cool, mount a THCAD-300 in the plasma case, run 24 volts to the plasma on one pair of wires, and add a 5 volt buck converter to power the THCAD and then send the output back on another pair. Because its sending a frequency back its more immune to noise than normal...

cdedwards
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Re: new to me hypertherm 900

Post by cdedwards » Mon Aug 03, 2020 9:05 am

the 24volts is for the torch on/off relay?

Rodw
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Re: new to me hypertherm 900

Post by Rodw » Mon Aug 03, 2020 3:56 pm

No, to power the THCAD via a 5V buck power supply.. Use a couple of spare wires to take 24v back to the plasma cutter and add something like this and clip the USB plug off for the THCAD power although there are open frame ones a bit cheaper
https://www.ebay.com/itm/DC-DC-Buck-Ste ... 0005.m1851

If need be, mount the thacd in a seperate metal box and mount to the plasma case.

Then use another 2 wires for the frequency output to go back to the plasma cutter.

The ArcOK via your reed switch Will need one wire attached to field power (+24v) and the other side to a 7i96 or 7i76e input.

The torch on switch will be triggered from one of the 7i96 outputs that has a built in relay (polarity is important) or in the case of the 7i76e you can use the built in spindle on relay or to a relay attached to an output (what I did).

So 8 wires in total. You could use an ethernet cable but they are not the most robust choice..

When attaching electro mechanical relays to a Mesa output, you attach one side of the coil to an output and the other side to field power ground (-24v)
Always use a flyback diode across those relay coil connectors (eg IN4001, IN4007 or similar) with the band on the diode pointing towards the mesa output.

Lastly, if the reed switch has a minimum current rating, add a pull down resistor from the ArcOK Input pin to ground to prevent contact oxidisation. Size this so it will ensure more than the minimum current passes through the switch. I used a 1W 1K resistor which will put about 100 mA through the contacts..

cdedwards
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Joined: Sun Jul 01, 2012 5:41 pm

Re: new to me hypertherm 900

Post by cdedwards » Mon Aug 03, 2020 4:12 pm

thanks. I added a open frame 5v ps that I had kicking about and the thcad to the frame inside the 900 right where the cpc boards would have been installed. Ran 110v to the 5v ps. 6 wires should do me. 2 for ArcOK on the reed switch, 2 for torch on and 2 for freq out +/-

Took out the pressure indicator from the hypertherm 800 and replaced the one in the 900. The 800 is now up on ebay for sale as non-working. maybe I can make some of my money back.
s-l500.jpg
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cdedwards
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Re: new to me hypertherm 900

Post by cdedwards » Sat Aug 08, 2020 6:09 pm

Well after some work, I have a thcad-300 mounted and a 5volt power supply in the 900. I've wired up everything before in what I hope is the correct locations avoiding transformers etc. Unfortunately I don't think I have pilot arc in this 900. The JP1 connector which is supposed to goto pilot arc, is not connected to anything whereas it should be connected to a circuit board and IGBT. I robbed an 8 pin connector from the 800 which was not doing anything and connected it to the 4 pin JP3 which will give me my torch on connector. Also installed a 8 pin connector on the back of the machine in a convenient hole and I'll wire it up for connection to the rest of the electronics.
IMG_1008.jpg
IMG_1007.jpg
IMG_1006.jpg
IMG_1005.jpg

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Rodw
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Re: new to me hypertherm 900

Post by Rodw » Sat Aug 08, 2020 7:00 pm

So the thcad-300 will fail spectacularly if its exposed to the HF start voltage which is apparently up around 25,000 V.
The soliution is to wire it in before the HF start module.

The expert on this is Tommylight on the Linuxcnc forum. Share some photos there and get his feedback before turning on that torch!

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