Generator project.

Discussion in 'Survival & Sustenance Living Forum' started by erikthebald, Oct 13, 2011.

  1. erikthebald

    erikthebald New Member

    115
    0
    0
    I've got a running 150cc gasoline engine I'm going to try to build into a 120 volt generator.

    My three phase theory may be a little rusty but I figure it'll give me something to pass the time working on this winter. We got our first snow a month early so I'm betting on a rough one.

    Anyone who has seen or heard about something like this done I'd appreciate a steer-in. diagrams or blueprints or what have you.

    Tough part, I think, will be devising a reliable starting system. It has a key start right now but that's got some solid state so I want to convert it to a pull start or similar. EMP proof. Maybe replace the kick start with a crank?

    Still thinking out loud at this point but I've got a rough idea for the frame on paper. uses the existing mounting holes.

    I do realize I could go buy one but then I wouldn't know how to build one, would I? This way, if anything goes wrong with it, I'll know exactly what I'm dealing with.
     
  2. c3shooter

    c3shooter Administrator Staff Member

    21,343
    214
    63
    Well, 150 cc will give you about 10 hp- at full throttle. However, IF that is an air cooled motorcycle engine, it is cooled by moving thru the air- tend to overheat sitting still.

    Generator motors are meant to run at a constant speed for long periods- can yours? Next, check the speed you have on output, and speed generator needs to turn. You MAY have to gear up or down.

    An automotive generator is not a generator- it is an alternator- and needs electrical power for the electromagnets when it first starts running. A generator has permanent magnets, and can "cold start".

    What do you want to generate? 12 v dc for charging batteries, 120 AC to run appliances?
     

  3. hiwall

    hiwall Well-Known Member

    4,269
    22
    48
    You could mount a fan blade between the motor and generator to cool both.
     
  4. Bidah

    Bidah New Member

    212
    0
    0
    Off the shelf generator heads generally come in 2 speeds, 1800rpm and 3600rpm. The 3600 rpm is meant to be used with air cooled engines since that is where they *tend* to want to run (outside of gearing). The 1800rpm ones are generally what you see on the liquid cooled engines that run at a lower rpm.

    I know a guy that got into a 40kW head, and hooked up a Dodge 360 with the automatic transmission to get the speed right. Maybe not pretty, but it works.
     
  5. erikthebald

    erikthebald New Member

    115
    0
    0
    Shooter

    Valid points, and exactly the kind of critiques I'm looking for.

    Since it's be intended to run indoors, closed off but ventilated to the outdoors, I'm thinking I can use the little 12 volt alternator it already has to power about a dozen cooling fans. If there is one thing I'm not fuzzy on, it's heat sinks so I'm thinking something along the lines of big metal sinks bolted on with fins to dissipate unwanted heat might handle that issue.

    Again, this is still in the preliminary, planning stage. It may prove unrealistic, or untenable, but I like a good project and it exercises the brain. Since the motor was free, I won't be out any $$$

    If I can't make this work, I'll turn it into a little paddle boat. I've already got a diagram for that. But, maybe not as useful in the mountains.
     
  6. c3shooter

    c3shooter Administrator Staff Member

    21,343
    214
    63
    I am not going to tell you what a really bad idea that is for several reasons..........




    But if anything happens to you- can I have your guns? :rolleyes:
     
  7. erikthebald

    erikthebald New Member

    115
    0
    0
    Not inside the house proper

    I HAVE heard of carbon monoxide. But, I should have been more specific.

    In any case, it won't be an issue.
     
  8. PerpetualStudent

    PerpetualStudent New Member

    76
    0
    0
    So, that's an affirmative on the guns going to C3 in the case of your demise?

    LoL.

    Seriously, this is an interesting topic. I've always been curious about the logistics of doing this.
     
  9. Jimmy

    Jimmy New Member

    134
    0
    0
    1. you have to know what you want to have power for.
    2. You are not clear in what equitment you have to work with.
    3. Are you using the altenator that comes with this engine? How many amps at 12 volts is it?
    4. Are you wanting to use as 120 volt ac or 12 volt dc and charge batteries?

    The small altenator on your engine will have minimum watts to run very much. It was designed to charge a small battery, a couple of lights, run the engine. You would come out better having an altenator in the 100 amp range and mount a pulley on the engine and power it with your engine and charge a battery.

    Sorry I'm limited to my phone right now. But provide more info, and I can give you a lot more guidance. I have built several homemade gensets thru the years. Hope this helps.

    Jimmy
     
  10. moonpie

    moonpie New Member

    174
    0
    0
  11. Irishgiant215

    Irishgiant215 New Member

    27
    0
    0
  12. Jimmy

    Jimmy New Member

    134
    0
    0
  13. c3shooter

    c3shooter Administrator Staff Member

    21,343
    214
    63
    If you build one like his, go get a deep cycle marine battery, like the one you use for a trolling motor. About 115 Amp hrs, around $67 from Wally World. Regular car batteries are not made to go from full charge to full discharge and back- they will quit real soon if you do that. A 5 hp motor could turn two of those alternators at once, doubling your charge rate- but he did a decent job for a "what junk do I have in the garage?" project- and those can be fun.
     
  14. oneshot

    oneshot New Member

    152
    0
    0
    The first question I would have would be how big of a fuel tank do you have for this motor? If it is only going to run a hour between filling I would think about rigging up something bigger. The second question I have for you is the 3 phase you mentioned about? If you are planning to use this for your house I would have to say single phase 240 volts ( two hots and a neutral ) would be what you what. The last thing I will bring up is some sort of transfer switch. This could be as simple as unplugging the T.V and olugging it back into the generator or as fance as a automatic transfer switch. Either way you DO NOT want to back feed the line coming in from the power company. Not only would you indanger the lifes of the line crews working in your area but will do damage to the transformer on the pole. We do a lot of work with generators more in the 45k to 65k range but if you have a question I can try to answer it for you.