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Bad voltage divider? PM65

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68rscamaro
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Location: Idaho Falls

Bad voltage divider? PM65

Postby 68rscamaro » Mon Feb 05, 2018 1:20 pm

I've been running this table for over a year with no issues. Even cut a bunch of parts friday with no problems. started it up this morning to cut some parts and the voltage reading on the screen is bouncing all over the place from 0-65ish. It usually just sits at 0. Any insight on what to check would be appreciated!

motoguy
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Re: Bad voltage divider? PM65

Postby motoguy » Mon Feb 05, 2018 3:34 pm

What table controls are you running? per Jim colt:

"The way to check the voltage divider output is to cut a part with the torch at a fixed height...then read the voltage divided output voltage on pins 5 and 6 at the CPC receptacle on the Powermax45. This will read 1/50th of the actual arc voltage....so pins 5 to 6 will be between 1.5 and 3 volts dc while cutting. A reading while firing a pilot arc is mostly irrelevant.....as you have not created a work path through the work clamp.

On the Powermax45...if the voltage divider is bad, it is likely a failure on the main power board. Because that is costly...you could use the voltage divider module from CandCNC.com....might be a better solution.

I would be surprised if a lightning surge would feed back through the CandCNC electronics without causing damage there as well.

Jim Colt Hypertherm"
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

motoguy
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Re: Bad voltage divider? PM65

Postby motoguy » Mon Feb 05, 2018 3:35 pm

Voltage divider on my PM85 went bad. I installed the CandCNC RAV-02 board, and it's been fine since.
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

motoguy
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Re: Bad voltage divider? PM65

Postby motoguy » Mon Feb 05, 2018 3:36 pm

Another thread that may help.

viewtopic.php?t=19833
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

68rscamaro
Posts: 3
Joined: Tue Jul 01, 2014 3:34 pm
Location: Idaho Falls

Re: Bad voltage divider? PM65

Postby 68rscamaro » Mon Feb 05, 2018 5:04 pm

I might try the rav-02 you mentioned. Fairly easy to install?

motoguy
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Re: Bad voltage divider? PM65

Postby motoguy » Mon Feb 05, 2018 8:46 pm

The hardest part was finding a place to mount it.
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

motoguy
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Re: Bad voltage divider? PM65

Postby motoguy » Mon Feb 05, 2018 8:46 pm

Interestingly enough, the techs (2) I spoke with at Hypertherm Tech Support both recommended the CandCNC RAV-02 vs doing a warranty repair on my unit.
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

urbnsr
Posts: 328
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Re: Bad voltage divider? PM65

Postby urbnsr » Tue Feb 06, 2018 4:33 pm

Is the voltage divider circuit part of the CPC port upgrade on the Hypertherm? If so, a replacement would be my choice - especially under warranty.

motoguy
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Re: Bad voltage divider? PM65

Postby motoguy » Tue Feb 06, 2018 5:01 pm

urbnsr wrote:Is the voltage divider circuit part of the CPC port upgrade on the Hypertherm? If so, a replacement would be my choice - especially under warranty.


My machine was (and is still) under warranty. However, every warranty center in the state was quoting MONTHS lead time to work on it. I called Hypertherm, and they gave me contact information for some warranty centers out of state. Same deal...NOBODY would quote less than a month to work on it. And that wasn't "we'll get you on the list, you can ship it a week before your name is up". That was "once it arrives, we'll put you on the list".

I offered to buy a replacement voltage divider card outright. It was $120 or so, IIRC. Far better than waiting for warranty work. However, HT said they couldn't guarantee it was the divider card, and not the main board, without having a certified tech (ie, warranty center) check it out. The main board is ~$900, IIRC. And there are no returns on these components.

HT warranty may be nice, but for me in this instance, it was worthless. I paid $50 for the RAV-02 card, paid next day shipping, and was up and running within 3 days. My machine is STILL running that RAV-02 card as a voltage divider, and my PM85 is under warranty until fall of this year...

At least one other user I'm aware of ran into a similar situation. He just bought a 2nd PM85, and sold his original when it returned from warranty repairs. I wasn't in a position to be able to do that.
Last edited by motoguy on Sun Feb 11, 2018 12:48 pm, edited 1 time in total.
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

urbnsr
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Re: Bad voltage divider? PM65

Postby urbnsr » Tue Feb 06, 2018 5:48 pm

I understand. Good points.

jimcolt
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Re: Bad voltage divider? PM65

Postby jimcolt » Sun Feb 11, 2018 12:10 pm

Have you verified that the voltage divider output is good or bad? There is a small board in the unit that is part of the CPC upgrade kit (factory installed if the Powermax was purchased that way).....that board could be bad......or the output from the main power board could be bad. If either was bad you would get a zero voltage reading on pins 5 and 6 (DC volts, 10 volt scale on a meter) while cutting with the torch. If no DC output....then further tests will need to be done to determine which board is bad (or is there a loose wire connection in the wire harness). Either board should be covered under warranty. The RAV card from CandCNC is often the quickest and lowest cost way to solve this as it connects to Raw arc voltage inside the Powermax....which is available (your torch would not fire an arc if it was not present). Jim Colt Hypertherm


motoguy wrote:
urbnsr wrote:Is the voltage divider circuit part of the CPC port upgrade on the Hypertherm? If so, a replacement would be my choice - especially under warranty.


No, it's not. It's a separate card in the machine. My machine was (and is still) under warranty. However, every warranty center in the state was quoting MONTHS lead time to work on it. I called Hypertherm, and they gave me contact information for some warranty centers out of state. Same deal...NOBODY would quote less than a month to work on it. And that wasn't "we'll get you on the list, you can ship it a week before your name is up". That was "once it arrives, we'll put you on the list".

I offered to buy a replacement voltage divider card outright. It was $120 or so, IIRC. Far better than waiting for warranty work. However, HT said they couldn't guarantee it was the divider card, and not the main board, without having a certified tech (ie, warranty center) check it out. The main board is ~$900, IIRC. And there are no returns on these components.

HT warranty may be nice, but for me in this instance, it was worthless. I paid $50 for the RAV-02 card, paid next day shipping, and was up and running within 3 days. My machine is STILL running that RAV-02 card as a voltage divider, and my PM85 is under warranty until fall of this year...

At least one other user I'm aware of ran into a similar situation. He just bought a 2nd PM85, and sold his original when it returned from warranty repairs. I wasn't in a position to be able to do that.

tcaudle
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Re: Bad voltage divider? PM65

Postby tcaudle » Sun Feb 11, 2018 1:22 pm

The key is to understand that the Hypertherm internal divider is in two parts. The PRIMARY divider and filter circuit is on the Main Card. Call it a "predivider", then there is the secondary divider card lets you pick from several different ratios. In most circumstances it's the main board section that takes the most stress and is more often the one that goes out.

The RAV-02 is made to work with the CandCNC PWM (THC SENSOR) module and is not a general purpose raw voltage divider for all THC applications.
It is a viable alternative (and cheap) if you do have the DTHC/DTHC II/DTHCIV system. Because the RAV-02 is made to work with a wide range of Plasma Cutters (including the ESAB CD start and older HF arc gap start machines it got lots of protection and lots of HF filtering.


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