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Thread: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

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    for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I have the chance to pick up a vintage coffee grinder that I have been looking for for a while. A real beauty. However it runs on 3 phase power. Is there any way I can run such a machine off my standard household power system?

    If I get the answer I want I will grab it and post images here straight away...


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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    If it came from a sponsor in Canberra then it is very cool *8-) The answer is that yes it can be done and there is several methods to do it.

    The old fashioned method is to use a large single phase 240V motor to drive a 3 phase motor as a generator to make the 415V. Clunky cumbersome bulkky and very reliable.

    Second method is to buy a 240V input 415V variable speed drive. You might pick up one at an electrical disposals place cheap or it will cost you a pretty penny new. Neat and tidy and variable speed but potentially expensive.

    Third option is to repower the grinder with a Cap Start Cap Run (high torque) 240V motor, while this is an engineering fiddle and will require maching of shafts etc. I have done this with pumps in the past and grinders are much the same as some of those. Most likely still the cheapest option in spite of the engineering.

    4th option is just to polish it up and admire it *:)

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Id vote for the 3rd option above too...

    Would definitely be more economical than 1-Ph/3-Ph Inverter Drive but you could always ask around at the various Industrial Electronics suppliers for "known" good used units but I dont think they will be very common on the ground.....

    Itd all come down to the method used to mount the motor in the grinder housing and whether this can be adapted to the fitment of a suitable 1-Ph motor. Quite a few grinder manufacturers also use the grinder housing as the motor casing and if this is the case with your 3-Ph jobbie, then it will become a more difficult proposition but not necessarily impossible.

    As an aside, 3-Phase motors can not be used as 3-Phase generators as all you would be able to generate, is VARs (reactive power) and not able to do any actual work. You would need a genuine 3-Ph Alternator (with prime mover) and these cost big bickies... :(

    Mal.

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    thanks guys- apparently the grinder weighs in at a massive 40KGs so I am having second thoughts... but I doubt I can resist.

    It has a very unusual shape and I wouldnt be surprised if swapping out the motor proves very difficult.

    anyhoo- I will post here if I get it.

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Use it for a door stopper or it will make for a great coffee table base I reckon ;)

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Quote Originally Posted by 7F52565A573B0 link=1271313871/2#2 date=1271322264
    As an aside, 3-Phase motors can not be used as 3-Phase generators as all you would be able to generate, is VARs (reactive power) and not able to do any actual work
    Ive just re-read what Ive written here and realised that Ive written the opposite of what I intended...

    I should have written...

    "As an aside, 3-Phase motors can not be used as 3-Phase generators, in isolation with a Reactive Load, as you would be not be able to generate VARs (reactive power required by the load) and not therefore, be able to do any effective work. Asynchronous generators (which this arrangement is representative of), depend on "slip" between the speed of the Rotor and the Rotating Field being generated in the Stator, which in turn supplies the circuit load.

    There are all sorts of problems associated with trying to use a 3-Ph Motor as an Asynchronous Generator in this way, when supplying a Reactive Load. Its really something not worth trying" ....

    Mal.

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Last time I talked VARS was a VERY long time ago too *;) It was more meant that you can buy this thing as a black box with the motor and generator fitted to do the job for Jack rather than the nitty gritty :) One of these things http://www.phasechanger.com/

    Not that Jack is owning up to it but I think its one of these behemoths 8-)


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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Hi Snobs ,
    * * * * * * * having both the big lathe and the mill/drill (both 1 hp ) running off single 240V in to 240V *3 phase out electronic variable speed drives , they work really well . Running a grinder might be very good , taking the grinder blade speed down to even 20 % of the usual speed .The only problems with VSDs (Variable Speed Drives - or Variable Frequency Drives ) is that the motors may be noisier , and any cooling fans run off the motors are also running at a different speed - reduced cooling , and a possible hazard to motor winding varnish over long periods . Both of my motors are new , so I havent had any experience with older 3 phase motors - and it could be ... problematic..
    "walk gently and carry a big insulated stick ,...
    *and a licenced *electrical specialist"

    pip.

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Thats an awesome grinder "bf"..... 8-)

    I can understand why it is so desirable....

    Gday "pip".... :)

    Out of interest, what sort of ballpark figure would one expect to pay for one of the VS drives you have?

    Mal.

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    pip
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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Morning snobs,
    *single to 3 phase 2 Hp *VSD controllers are around $320 new in Melbourne , and I paid $150 each for my 1 Hp controllers on Eb*y ( and its a gamble with power electronics there !) *-- and theres the cost of a qualified service person , an enclosure etc *.. and the possibility that it just wont work properly ..
    But it would be a sensational thing to have it running really well .

    pip.

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Thanks very much for that info pip.... [smiley=thumbsup.gif] :)

    Cheers,
    Mal.

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    I thought a motor winder could do a change or is there some physical limitation?

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    Re: for the Electricians: 3 phase coffee grinder- can it be used on regular power source?

    Quote Originally Posted by 1E382F0E2223393F2C2E39223F4D0 link=1271313871/11#11 date=1272003060
    I thought a motor winder could do a change or is there some physical limitation?
    Gday SubC.... :)

    It all depends on the stator design.... If the design makes it feasible, then sure, it can be done but it wouldnt be cheap. More economical to retro-fit a suitable 1-Ph motor I believe....

    Mal.



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