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  • #16
    Hi again,
    OK, so I can use a scope to check the power coming in. I have an old PHILIPS Pm 3231 scope with leads. Will this work?
    Oszi PM3231 - YouTube
    And again, even if I find a problem how do I reasonably protect the circuit?
    I cannot sell my customer on a surge protector if it has to be reset constantly; this is a high volume cafe.
    I cannot even find anything on a "slow turn on" on a google search that isn't related to relatively low-amp stereophonic and electronic equipment. This is a 2 group espresso machine with a 3500W element.
    My client isnt going to invest in a Liebert/Emmerson UPS with batteries and inverters just to keep the espresso machine I sold them from frying the card? In any reasonable client's POV it is my problem. Especially when pretty much every other installation I've seen has been running volumetric machines for years with absolutely no special protection of any kind.
    Unfortunately the live music events taking place several times a week at this place make up a significant portion of the cafe's revenue, and a lot of the bands playing there bring their own equipment, so rather than chasing sources of noise or asking them to give up hosting out of town bands, I need to find a cost effective way to protect the circuit. The 2-group Simonelli that this machine replaced worked there for years and the autofill box never fried. Their perception going into this purchase as well, was that volumetric machines were to be avoided because the brain boxes tend to fry and hamstring the machine. 3 months in, and that's exactly what has happened.

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    • #17
      Can't reply now but no don't do that.

      Start with the voltage to see if it's that simple. Don't touch it with a scope.

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      • #18
        Thanks a lot, you guys are great.

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        • #19
          Alright, basically, yes you can measure line-level (110-240V) power on a scope but you need to do it right/with the right scope or you risk blowing up the scope or yourself. I'm not familiar enough with scopes to comment beyond that so all I'll say is don't do it without due diligence or better yet get someone with a power scope who knows what's up to do it for you.

          As I said, if you haven't tested the voltage at the pony board and at the panel supplying the pony board under the three conditions I mentioned then the solution may yet be simple.

          If you can do that, post the values up here.

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          • #20
            Originally posted by skydragondave View Post
            Hi again,

            And again, even if I find a problem how do I reasonably protect the circuit?
            I cannot sell my customer on a surge protector if it has to be reset constantly; this is a high volume cafe.
            I cannot even find anything on a "slow turn on" on a google search that isn't related to relatively low-amp stereophonic and electronic equipment. This is a 2 group espresso machine with a 3500W element.
            My client isnt going to invest in a Liebert/Emmerson UPS with batteries and inverters just to keep the espresso machine I sold them from frying the card? In any reasonable client's POV it is my problem. Especially when pretty much every other installation I've seen has been running volumetric machines for years with absolutely no special protection of any kind.
            Unfortunately the live music events taking place several times a week at this place make up a significant portion of the cafe's revenue, and a lot of the bands playing there bring their own equipment, so rather than chasing sources of noise or asking them to give up hosting out of town bands, I need to find a cost effective way to protect the circuit. The 2-group Simonelli that this machine replaced worked there for years and the autofill box never fried. Their perception going into this purchase as well, was that volumetric machines were to be avoided because the brain boxes tend to fry and hamstring the machine. 3 months in, and that's exactly what has happened.
            I feel your pain.
            Slow turn on circuits are actually made for really big stuff as well, however the cost gets silly really quickly. A client of mine installed them on their 90Kva electric motors - not a misprint - for just over $5,000 a pop around ten years ago in Aust. Unfortunately, the only other ones I know of "first hand" are in my circa 2Kva per channel MOSFET power amps and are closely matched to the unit.
            The more I think about it, an UPS is probably useless in your case, as the grid probably cannot provide the grunt to run bigger ones anyway. FYI, I installed several 5Kva Lieberts in Aust, and I know I could get bigger ones than that over here at the time.
            FWIW, Javaphile may be spot on in talking about RFI, which adds even more complexity. Evil stuff when it strikes.

            My only suggestion is to find a nearby uni with an electrical engineering Dept and ask them - nothing beats local knowledge.

            All the best.

            TampIt

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            • #21
              Just a wild guess here, but if I understand correctly the 240V in the shop is being obtained by connecting the machine across two 120V phases, no?

              In this case, what the machine is seeing is not the same as the single phase, 240V, supply it was designed for. The peak voltage of each phase will be 120 degrees apart, and while this won't worry the simpler components, such as the heating elements, it could well have a detrimental effect on the electronics, especially if they involve switch mode power supplies which are often intolerant of complex input waveforms which will have a high harmonic content.

              As possible way around this problem would be to have the machines rewired internally so the the electronics are supplied via a single phase (say active to ground) and a 120/240V step up transformer - this way the elements and pump, which are the big power consumers, can get the complex, but cheap, two phase version of 240V while the electronics, which are a modest power requirement, can be supplied with a clean single phase 240V supply via a comparatively light and cheap transformer - or at least light and cheap compared to running the entire machine this way. The downside to this is that if the machine was ever plugged into to a single phase 240V supply the electronics would be supplied with 480V, so some sort of protection labeling would be needed to warn of the modification.

              Other options:

              Explain to the shop owner that the modern machine requires a better power supply and that they need to install a proper single phase 240V feed.

              Identify the point at which this shop becomes an unprofitable customer and tell them that you are no longer able to supply/service their machines.

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