Step up Xformer Question - Amp

Discussion in 'Amateur Radio Amplifiers' started by KK4YDR, Dec 19, 2015.

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  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    If stuff has proper circuit breakers, and the hot tub should have a GFCI, this is all pretty safe.

    I use a 240V 'extension cord' for our hot tub, and it's all outside but has a GFCI outlet. Been working fine for over a decade.
     
  2. KM1H

    KM1H Ham Member QRZ Page

    GMC/Chebby Suburban, beefed 454 and 8 + alternators.
    3 phase HV transformers
     
  3. KK4YDR

    KK4YDR Ham Member QRZ Page

    Sounds like X force amps owner who had a 25kw suburban
     
  4. AA7QQ

    AA7QQ Ham Member QRZ Page

    I rewound/rebuilt some leece neville & Chrysler alternators for the boys when I worked at an auto electric shop in the late 80s.
    Was the Burban black? If so, I know him. Just knew it was an AC system, as he never would tell anyone what he was running.
    I loaded up a few vans with 4-8D batteries & 3-4 alternators. 4/0 welding wire battery cables were fun to build.

    Ed
     
  5. WW1WW

    WW1WW Ham Member QRZ Page

    It will work perfectly. You will be able to get a KW out of 120 volt outlet, no problem.
     
  6. KM1H

    KM1H Ham Member QRZ Page

    That was a pretty generic description of what I saw and the van color rarely matched the owners:D The QRPers used the 318, 350, 360 engines; 440 Dodges were very scarce in vans but 454 GM/Chevy very common. I dont know what is popular these days as the rust belt has returned most to the ground.

    I had a Ford police package 260A alternator in a 94 Taurus and used it to feed a 3KW inverter at our summer place in Maine as regular power went out every time a moose farted or tried to mate with a pole. Gas was cheap, the car sipped it at idle. and it beat listening to a generator. The town finally got rewired and the car retired at about 330K 4 years later, still running but rust rot was even taking out the subframe and suspension.

    With junkyard 200A + alternators or ambulance or other 300A+ ones it wasnt hard to get a 25KW carrier for 20 seconds in a shootout. So our little troll doesnt wind up...none of those were mine however a huge shootout was a yearly event at the Dayton hamfest. BIG money was involved, prize and side bets.

    Carl
     
  7. N2EY

    N2EY Premium Subscriber QRZ Page

    I don't think it's a good idea. Here's why:

    First, since your shack isn't a long ways from the clothes dryer, the "extension cord" idea is probably simpler and cheaper.

    Second is the matter of voltage regulation of the supply at the amplifier end.

    Most amplifiers want a power supply voltage that doesn't change much from "standby" to "full power". Pulling near-full-power from a 120 volt branch circuit isn't the way to get that, and adding a step-up transformer makes it worse. This is why all those big amps don't even give the option of running on 120 volts, even though they could theoretically do so (a 20 amp 120 volt branch circuit can provide over 2000 watts and a 30 amp can provide over 3000 watts - but the voltage regulation from low- to high-load is something else.)

    Third, to make it even more of a sporting course, is "crest factor". Simply put, the typical modern amateur amplifier isn't a resistive load.

    So, in the end, I'd advise one of two things:

    1) Get a smaller amp (AL-80B?) that can run on 120 volts and use it. When you move, you can rewire it for 240 and continue to use it until you decide if the added watts are worth the added cost.

    2) Get a big amp and an "extension cord" that can use the dryer outlet. Make it as short and heavy as possible.

    Good luck!
     
  8. AA7QQ

    AA7QQ Ham Member QRZ Page

    And a week later was the nationwide shootout for the CBs at Dayton. Probably bigger money than the hams, by far. It wasn't uncommon to see 10 $100 bills under a windshield in the mid 80s. Probably much more in the 90s.

    Oh, the MA. shootout was always at Battery March Park in Quincy, MA on a Sunday. Right down the street from the FCC field office.

    Ed
     
  9. KK4YDR

    KK4YDR Ham Member QRZ Page

    I know there are mobile ham stations that do the 400 pills drive 2000 pills also but you will never hear whom they are.
    Thanks. If I make an extension cord I will just use 10/3 and put my own ends on it. Way less expensive than some $150 extension cord that is made in a factory.
     
  10. N2EY

    N2EY Premium Subscriber QRZ Page

    #10 is a good choice.

    Besides saving money, if you make it yourself you KNOW it is #10 wire, and you can make it the exact length needed. Extra length isn't good in this application.
     

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