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Thread: Time to buy a Megger

  1. #1
    Senior Member skydragondave's Avatar
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    Time to buy a Megger

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi folks,

    I've decided it's time to start investing in my side business repairing commercial coffee equipment. Among other things, I've decided to buy a Megger tester for testing elements and electric motor windings, but after looking at their website none of their equipment jumped out at me as the right ones to buy. What do you use?

    Also, if you have any other suggestions about what other equipment I should be investing in, like an ultrasonic cleaner, I would be grateful.

    As most of you are in Australia you can be assured I won't be muscling-in on your business. You guys have been great and I am getting addicted to these wonderful machines. Thanks for the help!

  2. #2
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    Actually, virtually all you will ever need is an el cheapo continuity tester for electric elements. Most of all the other functions on a multi meter will remain unused for years, and I dont know the last time we tried to test windings on an electrric motor. It either runs or it doesnt, and if it doesnt odds are its usually the capacitor (another hard earned tip given away).

    Ultrasonic cleaners are great but note:

    In order to use for all you would need one with a large tub, not a walmart special just big enough to clean wedding rings or at the most a pair of spectacles! The large ones then are not cheap to buy. We have one that is bigger in toto (for size comarison), than a large sized upright washing machine and the tub still isnt as big as a single laundry tub.

    However you probably wouldnt use it all that often for regular machines (therefore not really cost effective to have one and not use often), while they are very handy for cleaning up parts for domestics and autos (just my opinion).

    The ultrasonic cleaner is nice to have if you pick it up for the right price from a clearing sale in close to working condition, but I wouldnt rush out to buy a new industrial size one at full price because you can get by perfectly well without one.

    Our Test and Tag machine is very useful and used widely, but we also need to have the qualification to be allowed to "drive it".

    Otherwise you are loooking at a wide range of conventional tools and a well set up and organised work space. That really is the secret.

    Note just because one doesnt necessarily need a range of specialised tools etc its not an open invitation for one and all to take up the opportunity to go into a new "profession" of coffee machine repair. The secret as always is in the level of expertise and experience of the tradesman.

    And of course, others may have differing opinions.

    PS one of the best and most experienced old school esp machine mechanics I ever knew had, as his main "specialty tool", one of those little screw drivers with the light in the handle that lights up when a circuit is completed. That and a tool box with his good quality spanners. That was all that was required in the end for most run of the mill repairs.
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  3. #3
    Senior Member skydragondave's Avatar
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    Thanks for the reply, I just looked up test and tag machines. A very neat device. However test and tag protocol isn't a requirement in Canada, so I don't think any would be made that are compatible with NA voltage/frequency/plug and receptacle configuration.
    I work as an electric forklift truck mechanic as my day job, so I would definitely be able to make use of a Megger for motor testing. I was just wondering which one would test HX elements most effectively.
    What do you use your u/s cleaner for most often? I was thinking of trying to track down one large enough to dunk a 8L HX boiler into, anything larger I'd probably just scrape out.
    I hear you on everything else. I'm working on a larger space with a stainless bench and walls/floor that can be wiped down and sanitized, but want to make sure I get what I need to check these machines out as thoroughly as possible so I don't end up leaving anyone in the lurch. That's what it's really all about for me. Not willing to go fulltime until I'm knowledgeable enough to go over a machine top to bottom without asking for advice over here. Most of what I've found is pretty common to the machines I've worked on in the past but I've learned a ton already from this forum.
    Thanks for sharing your advice.

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    No worries. Whatever megger you have for your day job will be more than enough for checking circuits in espresso machines.

    Elements only need a simply continuity tester and as mentioned before, a simple electricians test screw drtiver is ample for that as you dont need to take a reading, just check there is or isnt continuity.

    We cant fit an 8 litre boiler in the tub of our ultrasonic, and even if the tub was large enough it still wouldnt be suitable because the lid of the ultrasonic comes down and the frame for that takes up space inside. Hard to explain without sending you a couple of photos with lid up but not at work today! There may be other types that dont have that kind of arrangement, but you would need to do some web searching to see what is available. Think of a machine the size of a commercial washing machine in a laundromat, with a much smaller sized tub in the top. The rest of the space underneath is taken up by all the hocus pocus paraphernalia that makes the ultrasonic thingo work, and from memory to buy one like ours new was something like 6000.00 USD last time I checked. To buy new would be a waste of money for our kind of work and we picked ours up at auction, I think it was ex hospital gear, so was good gear to start with (I think american made). On ours, the lid needs to close for the thing to do its job so probably cant do anything bigger than a 1 group commercial boiler.

    So far we havent really covered much more than conventional espresso machine mechanical stuff without touching on the electronics. These days electronic controls for esp machines are becoming more and more sophisticated eg PID controlled multi boiler machines, however its still really not much more than testing for completion of circuits or working out if something is switching or not. Ultimately once you've worked out that something has failed, you really cant waste any time trying to find the reason for the specific failure in the component (eg a failed 20 cent triac on a board or something) or trying to fix it (time is money and the end result whichever way you go is the client pays, except that you could be wasting a lot of your own time on one repair where you should have been on to the next 3 machines in the same period of time), you just replace the failed part.

    The expertise, is in being able to quickly trace where the real fault lies (in two parts: the failed component/s, and whatever caused it/them to fail upstream...same as in your own profession).

    I dont think I can add much more than that, because the rest is up to you gaining the expertise over time either by working with someone else apprenticeship style, or by the old sink or swim method. In my own workshop, I have a leading hand technician and two working under him. While the two blokes are good mechanical technicians, they need the diagnostic expertise of the leading hand for fault finding, thinking outside the square etc. and it takes them considerable time (years) to really come up to best possible standard.

    So now I know where to send my electric forklift next time it suffers an "inconvenience"!

    Good luck.
    Last edited by Fresh_Coffee; 3rd February 2013 at 01:19 PM.
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  5. #5
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    Quote Originally Posted by Fresh_Coffee View Post
    Elements only need a simply continuity tester and as mentioned before, a simple electricians test screw drtiver is ample for that as you dont need to take a reading, just check there is or isnt continuity.
    To test elements properly you DO need a Megger, since they don't just fail by going open circuit - sometimes they suffer insulation failure and short to earth via the boiler water or by moisture entering via the end of the insulation without actually going open circuit. I was called out in the afternoon on Australia Day to fix two machines on a cart at a major outdoor event that were both tripping breakers. On first test with the multimeter the elements on both tested OK, but testing with the Megger showed both elements were shorting out to earth. I suspect the fact the cart was stored in a shipping container painted dark grey and sitting in full sun since November when they were last used (except for a short period where they were kept in a coolroom for some reason) caused the problem by subjecting them to a far wider range of ambient temperatures than was good for them.
    Meggers are also invaluable for diagnosing hidden shorts in solenoid coils due to water ingress, by testing at the power plug with the Megger and unplugging solenoids one by one until the faulty one can be isolated.

    The one I'm using at the moment is this:
    TES-1600 Insulation Tester

    ..and I've got one of these to replace it for use on the road since it combines several functions, allowing me to carry one less test meter in the toolbag:

    Uni-Trend Group Limited
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  6. #6
    Senior Member skydragondave's Avatar
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    Quote Originally Posted by MorganGT View Post
    Wow. I could use that every day at work if it has multimeter functions with it, and the screen on my beat-up meter is on the way out anyway. I didn't know you could get both functions on one meter! Thanks, I'm going to start looking for just that this week. Cheers

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    [QUOTE=MorganGT;490834]To test elements properly you DO need a Megger, since they don't just fail by going open circuit - sometimes they suffer insulation failure and short to earth via the boiler water or by moisture entering via the end of the insulation without actually going open circuit......Meggers are also invaluable for diagnosing hidden shorts in solenoid coils due to water ingress, by testing at the power plug with the Megger and unplugging solenoids one by one until the faulty one can be isolated......QUOTE]


    Gosh you young blokes are a tool salesman's dream ! We do all this stuff with a simple el cheapo multi meter and by good old fashioned trickery and smarts !

    Perhaps the only other occasonally useful tool I can suggest is an amp meter...the type that has the loop that goes over the cord.

    See if I can dig up a photo of the ultrasonic for you.

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    Quote Originally Posted by Fresh_Coffee View Post
    Gosh you young blokes are a tool salesman's dream ! We do all this stuff with a simple el cheapo multi meter and by good old fashioned trickery and smarts !

    Perhaps the only other occasonally useful tool I can suggest is an amp meter...the type that has the loop that goes over the cord.
    My Meggers each cost me less than $50 by careful buying. I have a lot of the trickery and smarts you refer to, but when a customer is paying by the hour and losing business at the same time, I'm more interested in using the best tools that allow me to get their equipment up and running again quickly. I agree a clamp meter is also a very useful tool, I carry one of those as well.

    We've got a big commercial ultrasonic cleaner in our workshop too (was given it in lieu of payment of a few bills by a regular customer) and it gets used mostly as a spot to stack washed machine parts, since it sits in our our cleaning bay. We've found that putting a commercial machine boiler in (of all things) a 100-cup coffee urn full of diluted descaler and heating it works the best, although anything bigger than a 2 group machine generally needs to be done by inverting the boiler halfway through the cleaning, since you can't get all of it submerged at once.

  9. #9
    Site Sponsor coffee_machinist's Avatar
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    Quote Originally Posted by MorganGT View Post
    a 100-cup coffee urn full of diluted descaler
    NICE. I'm definitely putting that on the to-do list for the new workshop. You're an ideas man, Steve!

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    Re: Time to buy a Megger

    You can buy ultrasonic transducers as stand alone units (they are used for all kinds of applications).

    Has anyone ever tried building a unit which inserts into a boiler?

    I presume it would need a vent of some kind.

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    Hate to say it, but for simple continuity testing, a very cheap old fashioned analogue multi-metre is probably best. If the needle swings, she's OK.

  12. #12
    Site Sponsor coffee_machinist's Avatar
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    A Megger is not for simple continuity testing. It's for testing insulation resistance at high voltage to force a fault current condition that a multimeter would read as ok / infinite

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    Quote Originally Posted by coffee_machinist View Post
    A Megger is not for simple continuity testing. It's for testing insulation resistance at high voltage to force a fault current condition that a multimeter would read as ok / infinite
    Not arguing with that....simply saving that for simple continuity testing, a very cheap, analogue.....etc etc as I said. :-)

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    Quote Originally Posted by robusto View Post
    Not arguing with that....simply saving that for simple continuity testing, a very cheap, analogue.....etc etc as I said. :-)
    The only problem with that is that a lot of electrical faults in espresso machines involve coils or elements shorting to earth due to moisture getting where it shouldn't - 'simple continuity testing' has its place, but if that's the only method of testing you have available, it is easy to jump to the wrong conclusion about the nature of the fault, or miss a fault entirely. And a multimeter that does double duty as a Megger costs very little more than a multimeter that is of acceptable quality/reliability (a really cheap multimeter can be so erratic that it is of no use whatsoever for testing, since you end up being unable to trust the results).

    Oh, and one extra function it is very useful to have on a multimeter is capacitance testing - very useful if a machine or grinder is having issues with the motor starting. If the start capacitor tests as 90% or less of its 'rated' capacitance it's on the way out and needs replacing. But to test a capacitor safely and not damage the meter it needs to be shorted out to discharge it, so I carry a short wire link with a female spade terminal on each end to connect across the capacitor terminals first to let it discharge.

    And really, these days there are so many test meters of different sorts (of an acceptable standard/accuracy for espresso machine repair - they don't have to be top $ Fluke meters) that can be had cheaply and don't take up much room that there is really no excuse for not being properly equipped. Unfortunately a lot of people I have seen in the espresso machine repair business (and I don't think that includes anyone here) operate with a very basic set of tools, very little diagnostic/test equipment, and a very basic incomplete assortment of spare parts and consumables. We often get visits from a 'technician' who works for another service company to buy 2 group seals, 2 group showers, a couple of tap washers etc. since his boss doesn't bother to buy in a stock of spare parts.
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  15. #15
    Senior Member skydragondave's Avatar
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    Quote Originally Posted by MrJack View Post
    You can buy ultrasonic transducers as stand alone units (they are used for all kinds of applications).

    Has anyone ever tried building a unit which inserts into a boiler?

    I presume it would need a vent of some kind.
    American Piezo has a page dedicated to ultrasonic cleaning transducers. I posted the link but thought better of it and edited it out.

    This looks like a really interesting idea. A lot of those specs are out of my depth though... how would you size one for instance?

    I wouldn't mind taking a stab at it but it'll obviously take a lot of research. If anything comes of it I'll post it here!

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    Re: Time to buy a Megger

    Behmor Brazen - $249 - Free Freight
    Best bet would be to contact the supplier and discuss the application.

    I dont imagine they are cheap items!



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