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What a difference 20 volts makes

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  • What a difference 20 volts makes

    I work as an engineer on a gas carrier plying between Dampier (where "Red Dog" was filmed) and Japan, the ship was built in Japan, and so is 100 volt 60 Hz power.
    We do have 220 volt 60 Hz available, but the 10 Hz difference makes motors (fans) unhappy, as I found out when I tried to use an I-Roast-2 on the ship.

    So I bought a Gene Cafe roaster from Massachusetts in the United States, delivered to the ship.

    In hind sight I should have bought it from Japan as the USA is 120 volts 60 Hz, not the ships voltage, I thought it shouldn't make too much of a difference, wrong.

    A 200 gram roast would take almost an hour, with cool down time, and wouldn't get even close to the asked for temperature of 485 degrees F, just getting to 402 or so just before I hit cooling, more a slow bake than a roast.

    It was still better than stale beans, but I knew it could be better.

    In our recent docking in Singapore, I engineered a solution, by freeing up a 100 volt to 120 volt transformer that had been used to power two US in-sink-erators in the Galley and scullery.
    I replaced them with Japanese 100 volt units, so the transformer was surplus to requirements, woo hoo.
    I had spend days looking for a transformer on the ship that had the required 120% change to achieve the desired voltage but nothing came close, 415 volts to 440 volts is only 106% change in step up mode, but I discounted a double setup 106% x 106% as being too fiddly at 112.3%, requiring three stages to achieve 119%.

    Well I finally did my first roast at the correct voltage, and it has transformed the machines performance, and only takes 30 minutes, with cool down, to roast 200 grams, final temperature being almost 460 degrees F.

    One of the reasons I was less than happy with the speed of the Gene Cafe was in comparison to my Behmor 1600 plus I use at home, but I didn't want to take a Behmor machine to sea, even though its voltage selection feature would probably make it a working solution, as I have enough problems getting all my gear to follow me when I change ships as it is, and regularly abandon stuff.

    The beans are put through my Portaspresso Rosco grinder and Rossa TR for short blacks.

  • #2
    Sure can be confusing alright...

    As if what you describe isn't bad enough, Japan actually uses two different line frequencies, depending on which power grid (and supplier) you are connected to... basically 50Hz in the East and 60Hz in the West. You'd need to be very careful if you were travelling around and overnighting in various motels...



    • #3
      Ohms law in action !
      20% more voltage on the same resistive load, will give you 20% more current
      power is proportional to the square of the current so you will be upping the power (heat) by 40+ % !!
      ..( actually I guess you have simply brought the power level back up to its original spec, and you were more than 40% down previously )