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IndustryArena Forum > MetalWorking Machines > Cincinnati CNC > Cetroid Retrofit - Arrow 750??
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  1. #1
    Join Date
    Apr 2020
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    53

    Cetroid Retrofit - Arrow 750??

    I'm looking at retrofit options for my Arrow 750 but I'm not 100% sure how it all goes together.

    Will the oak board control my motors and spindle without the need for Kollmorgen drives?

  2. #2
    Join Date
    Mar 2011
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    460
    Quote Originally Posted by Burf86 View Post
    I'm looking at retrofit options for my Arrow 750 but I'm not 100% sure how it all goes together.

    Will the oak board control my motors and spindle without the need for Kollmorgen drives?
    I'm assuming you are referring to the Centroid control? I have not put one on a Cincinnati so can't speak from direct experience on an Arrow, but unless you plan on replacing the motors too, I would plan on keeping the Kollmorgen drives and using the Centroid +/- 10V signal with them.

  3. #3
    Join Date
    Apr 2020
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    53

    Re: Cetroid Retrofit - Arrow 750??

    Damn. The Kollmorgen spindle drive(VFS5) and power supply (PSR4/5A-250) keep failing so I'm looking for a way to get rid of them.

  4. #4
    Join Date
    Mar 2011
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    460
    Quote Originally Posted by Burf86 View Post
    Damn. The Kollmorgen spindle drive(VFS5) and power supply (PSR4/5A-250) keep failing so I'm looking for a way to get rid of them.
    The VFS5 and PSR should not "keep failing" unless there is something causing it. Have you had your motor checked out?
    I had one customer call me in after having their spindle drive repaired 2-3 times...I replaced their motor and they never had another issue.

    Is your Transformer set up correctly? If you are not using the one that came with the machine when new (dual wound, multi-tap, delta-Wye), this could be contributing to failures as I see rarely see failures on these machines that are using the transformer, and failures I do see are in shops that are not using it (most of these purchased the machine used and didn't realize the transformer should have come with it).

  5. #5
    Join Date
    Apr 2020
    Posts
    53

    Re: Cetroid Retrofit - Arrow 750??

    I haven't had the motor checked out, actually.
    The guys who I have had service my machine have just been exchanging the VFS5 or PSR when there has been a problem, they have never mentioned it could be the motor.
    I am using the original transformer, but I don't know if it has been set up correctly or not... I used a local electrician to wire up the machine when it first arrived but now you mention it he could have done a bad job of the transformer because the RCD he installed was not up to the job either... What do I need to look for there?

  6. #6
    Join Date
    Mar 2011
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    460
    I don't know who you are using, but unfortunately there are way too many people/companies out there that are not qualified to work on machines. All they can do is take a guess at what to replace and get rewarded with more $$ every time they get it wrong.

    I went to one customer after they got frustrated with their "factory trained technician" because in a 9 month period he had them spend over $25,000 sending their spindle drive out for repair three times, power supply once and spindle motor once. He told them the motor shop must have messed up the repair and he needed to send the motor out again (which is when they contacted me).

    I showed up and within 20 minutes was able to find the cause and show them the problem they were experiencing had nothing to do with the VFS5, PSR or Spindle motor. Their door interlock circuit was preventing the motor from getting all 3 legs. I think I charged them $900 including travel time to actually fix the problem while the other company made $10,000-15,000 for being wrong repeatedly and making the customer spend thousands more on unnecessary repairs.

    Regarding transformer, not too complicated...just make sure incoming to Delta side, Outgoing on Wye and output voltage in the 230VAC range. Any licenced electrician should be able to handle this easily but I find way too many they wired with as low as 198VAC or as high as 268VAC. Even had to fix one that the electrician wired 480 into the output side. Instead of dropping it to 230 he had it reversed and had it outputting close to 1000VAC when they turned it on.

  7. #7
    Join Date
    Apr 2020
    Posts
    53

    Re: Cetroid Retrofit - Arrow 750??

    I have been using John Hodson. Apparently, he worked for Cincinnati when they were still operational and he has been recommended a couple of times when I've asked for help. I'm not 100% sure about the quality I have received though. Some of the 'refurbished' drives I have received have still been pretty dirty on the inside and that's not what I would call refurbished, personally...

    Thanks for your help thus far, much appreciated. I'll get an electrical friend to have a look at the transformer with me and see if it matches up to what you say. Will make sure to not get electrocuted!

    Do you have a recommendation for someone this side of the pond (UK) who I should talk to?

  8. #8
    Join Date
    Mar 2011
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    460

    Re: Cetroid Retrofit - Arrow 750??

    With you in UK, I'm not positive if they used the same transformer. There were some differences for the US vs European market but the hookup should be essentially the same as I mentioned..

    I know of a few of the old factory guys in UK that went out on their own, but don't know much about them (other than MallardFizz who used to post here).

    Refurbished?, Used?....not sure there is much of a difference these days when you buy anything online. I was just at a shop yesterday that bought a "refurbished" power supply for their A2100, they put it in and couldn't get the control to power up after that. I went out to look at it for them and the "refurbished" power supply was shorted internally and blew a fuse in the machine and also took out the video card in the control (which Siemens quoted $1,200 to repair). Fortunately I also had a video card with me to keep them running until the repair is complete, but the sad thing is I stock new power supplies for less than they paid for the used/refurbished one so they could have avoided this completely, but they didn't call me first.

  9. #9
    Join Date
    Apr 2020
    Posts
    53

    Re: Cetroid Retrofit - Arrow 750??

    That's the thing, it wasn't something I purchased off the internet. I sent the drives back to Hodson machine tool and he replaced them with "refurbished" drives.

    You were right about the transformer... We changed the wiring to a lower output voltage and it's started working. Well kind of working...
    When I say we, it was a friend of mine who fixes welders and installs solar panels who figured it out with help from your suggestion. The machine was working fine for a year or so until we started to get into summer in April 2022. He thinks it was the solar panels recently installed on the housing estate around my workshop. Apparently, systems under 3kva don't need anti-insulating devices and so shift the power factor on mass.
    The mains supply was 418v AC rms but the peak was higher. He connected the input to the 460v terminals as it was going over-voltage due to the peak. It was on 415v. The output to the machine was 222v AC.

    I don't fully understand all of this electronics stuff if I'm honest...

    The machine doesn't cause the regen to glow red hot anymore. yay!
    The spindle will run and stop just fine up to 750rpm, but if I try to spin it at 800rpm or above the regen kicks in and slows the spindle slightly but then cuts out and the spindle just coasts to a stop and I get alarm 39-37

    The alarm mentions checking for spindle drift using the "spindle setup" patch and in MDI program M3S0 and check for spindle drift. Or it may be necessary to use the motion link to check the parameters.
    I have motion link and a computer needed to connect to the VFS and have used this setup to set the spindle orientation with the help of Mike Kilroy in the past.

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