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power supply ?

Discussion in 'Home Brew' started by BammBamm, Apr 15, 2011.

  1. BammBamm

    BammBamm Instigators ...173 on the southside.

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    I am a mechanic and have thought about building this so what's your thoughts.
    Using a 18" x 6' x 3/4" Piece of wood mount a furnace blower motor on one end driving by belt a 100 amp single wire alternator and connecting the alternator to a 1000cca gel cell battery and running the power from battery through a noise filter and into my Texas Star DX500V so it could be used as a base.
    I have all the parts just wondering if I'm wasting my time due to alternator whine? The power from the unit to the battery will run on 6 gauge cable and would be about 8 foot to amp as it would be in my garage which is on the other side of the wall from my radio desk. Seeing how I have all the parts it would be a lot cheaper than buying a high amp power supply. The alternator and battery would be grounded to a 6' copper ground rod about 4 foot from where they are mounted. Thanks for the thoughts/help.


     

  2. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    I doubt the motor has the horsepower to spin the alternator fast enough under full load. How many amps do you plan on pulling from this setup? Lets say 50 amps and at about 14 volts that is 700 watts input.Of course you loose some power to inefficiencies but bear in mind that 1 horsepower is equal to about 746 watts so it would take at the very least a full horsepower motor to run that setup and more than likely twice that to run good. I have run a 4 Hp gas engine driving an alternator to recharge a battery at a campsite and under a heavy load the motor would slow down a bit.
     
  3. unit_399

    unit_399 EL CAPO

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    COOL !!! I learned something new today. Thanks Cap'n Kilo.

    - 399
     
  4. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Don't thank me, thank my little converter program. I use this a lot. it will convert almost anything to almost anything else.

    convert program
     
  5. BammBamm

    BammBamm Instigators ...173 on the southside.

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    Thank you that let's me know not to waste my time doing this and to keep saving for a power supply. I had thought of a gas engine but didn't want the noise from it.
     
  6. mackmobile43

    mackmobile43 Jock Supporter

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    If you can come up with a 5 hp electric motor then you'll be happy but the cost/power is way on the cost side.

    A switch style power supply is you best option and you can use a battery with that and charge it also, batteries are nice and cover spikes in current draw in SSB mode, I use Iota supplies and have no IF issues on any band that I can detect.
     
  7. BammBamm

    BammBamm Instigators ...173 on the southside.

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    I am currently having fun talking skip without a amp but would like to put my radio and amp together and be able to bring it in the house at night and hook it to power. I am thinking of selling a lot of gear such as my other base and base amp. I guess if I sell the base I could buy a power supply. That is until the wife finds out! This is how she looks as I spend money on radio stuff:blink:
     
  8. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    That's not too bad. My wife still has no idea just how much I will be spending rebuilding my complete HF antenna system from the ground up. Literally I mean from the ground up. She is already looking at me like this :sneaky2:. When she finds out exactly what the new 56 foot Trylon Titan tower, Yaesu G-2800-DXA rotator, DB-1217 yagi for 12m and 17m, on top of what I already spent on an Explorer-14 tribander and the 40m add-on kit as well as the Ameritron remote coaxial switch she will be looking at me like this :eek: and then :censored: I have a feeling it will be a long time before she looks at me like this :p: Oh well the den/shack is comfy. :laugh:
     
  9. ElectronTubesRule

    ElectronTubesRule Active Member

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    I do not think it is a waste of time but why do that when you can get a suitable switching power supply for $149-$195 off ebay with the right current capacity. IN fact you might even be able to get one for $95 off ebay if you watch it and bid smartly.

    Most amatuers today use switching power supplies for transistor amp's.

    Alternators should not wine if they are wining then they usually have something in the diodes or rectifier area in general that has gone bad or is marginal.General Motor's and Ford have the noisiest alternators on earth and prob. it is a GM alternator you are thinking of using right???? My family has owned Toyota's since 1976 and have never had alternator wine ever. By the way I was trained as a Mechanic. If you put a wining altanator on an engine analyzer the old school scope type you can see the blown diode on the trace. Rebuilding with beefier diodes and rectifer combined with making sure all contact points are clean because aluminum oxidizes will prevent wining alternators. You can also adjust the output internally based on watt components you replace in the internal voltage regulator to taylor the output to what you want within reason.

    You would probably need to put a larger pulley on the alt. because most do not make much current at low speeds. Current is what you need most with an amplifier most systems can sustain the voltage needs but cannot keep pace with the current draw.

    When we jump start Tractor Trailer aka Big Rigs we have a gasoline or diesel V twin hooked to what looks like a large alternator or Lexindyne Generator. This way you do not need a power cord......I also made similar things back when I was into racing to charge the battery on the car between runs.


    P.S. Use 1ga-4ga wire for this hook up 8ga is not up to the job and is marginal at best. An old set of welding cables works nice two if you have old set laying around. Alway use something 4ga or larger for 99% of the run when talking about powering high current 12 volt devices then use the light weight stuff for the short runs so you ca hide it. I always had 1ga running from end to end in my vehicles and then hooked into that common hot and ground with lighter weight wire. In fact I would use 4ga for a 100watt amp so I think you need to spend a bit more on wire! You only need to buy it once and then you have it forever.
     

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