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15 HP RPC Build

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  • #46
    Originally posted by Doozer View Post
    You're emoting.
    When people emote,
    they don't think clearly.
    Get calm and
    Imagine the power flow.

    -D
    Actually I did just that. Imagine the power flow. When you cut the juice to the pony motor, the clutch will let go. Just like when you use a chain saw, you cut the throttle and it lets go. You can't back drive the engine with the chain. Tried that, and nope.
    25 miles north of Buffalo NY, USA

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    • #47
      The chain saw has much more friction than the pony is likely to. (and no power source fro the chain to reverse drive from) But see above.
      J Tiers
      Senior Member
      Last edited by J Tiers; 04-22-2021, 03:21 AM.
      3313 5160 4357 4344 3174 9120

      Keep eye on ball.
      Hashim Khan

      Everything not impossible is compulsory

      Birds are NOT real, they are spying on you

      Comment


      • #48
        Originally posted by nickel-city-fab View Post

        Actually I did just that. Imagine the power flow. When you cut the juice to the pony motor, the clutch will let go. Just like when you use a chain saw, you cut the throttle and it lets go. You can't back drive the engine with the chain. Tried that, and nope.
        Ride your mini-bike full throttle down a hill.
        Cut your ignition half way down the hill.
        The engine will keep spinning until the mini-bike
        slows down enough for the clutch to drop out.
        The bike going down the hill is adding energy
        back through the clutch and keeping the
        engine spinning, with cut off ignition.
        If you are going down a really long steep hill,
        the cut engine will keep spinning until you
        reach almost the bottom.

        -Doozer
        DZER

        Comment


        • #49
          You are the designer, so you get to build what you want. But I'm telling you, you do not need a clutch. The pony motor, once powered off, just spins happily for as long as the RPC is running. No reason not to KISS.

          The main reason to use an idler is to reduce the enormous surge startup current that flows through a Fitch Williams-type start capacitor network. Using an idler makes sense. Again, you can build whatever you want but my 15hp RPC uses a 3/4hp idler with no clutch. No belts squeal when it starts, it just spins right up.

          Disclaimer: I am the guy with the RPC designed by lakeside53. I can absolutely verify that it has been working for quite a number of years now. I can also tell you that when it comes to things electrical there is wisdom and there is wisdom. In other words, 10 people might chime in on a topic but only a much smaller number have any real deep knowledge of the subject. Lakeside53 is a person to pay attention to. Trust me.

          Here are some details from my build: to keep things as quiet as possible, my RPC sits on a rubber mat. Further, the idler motor has thick rubber "washers" it is mounted on. These are trivial touches, but quieter is easier to live with. Second, my RPC is in a small machinery room attached to the end of my shop which is under my house. Also in that room is my boiler and hot water heater. That room gets noticeably warmed when the RPC is running. In the winter, I take advantage of this by opening the machinery room door to let the heat in. In the summer, I use a small exhaust fan to blow the heat outdoors. Again, these are trivial matters but the end result is I don't have to heat my shop, and that's a big deal. (I'm in the Seattle area which has fairly temperate winters.)

          Another small touch that I continue to appreciate was adding 3 voltmeters showing the leg-to-leg voltages. Here's a not-so-great photo:



          It's very gratifying (and cool) to see all 3 meters reading very close to 240VAC. Means the balancing caps are working.

          If you are curious about the actual elements of my design electrically, lakeside53 already published the schematic above. I did make one change since then - I changed the output fuse block from 30A fuses to a 40A 3-pole breaker. I have several pushbutton stations around my shop. To turn on my RPC I just push the START button momentarily and that's it. The timer relay shuts off the pony motor after long enough for the idler to be up to speed (we chose 2 seconds). Dead easy. Reliable. Simple.

          metalmagpie
          metalmagpie
          Senior Member
          Last edited by metalmagpie; 04-23-2021, 11:42 AM.

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          • #50
            A clutch could work. But it would be simpler to just either let the belt come off after starting, or allow the pony to spin with the idler. Less fussing.

            A clutch would need some careful selection of engagement speed, type, torque capability, etc. What works for a snow thrower may not work for a pony motor.

            But a pony and belt will indeed just reliably work.
            3313 5160 4357 4344 3174 9120

            Keep eye on ball.
            Hashim Khan

            Everything not impossible is compulsory

            Birds are NOT real, they are spying on you

            Comment


            • #51
              Originally posted by metalmagpie View Post
              You are the designer, so you get to build what you want. But I'm telling you, you do not need a clutch. The pony motor, once powered off, just spins happily for as long as the RPC is running. No reason not to KISS.

              The main reason to use an idler is to reduce the enormous surge startup current that flows through a Fitch Williams-type start capacitor network. Using an idler makes sense. Again, you can build whatever you want but my 15hp RPC uses a 3/4hp idler with no clutch. No belts squeal when it starts, it just spins right up.

              Disclaimer: I am the guy with the RPC designed by lakeside53. I can absolutely verify that it has been working for quite a number of years now. I can also tell you that when it comes to things electrical there is wisdom and there is wisdom. In other words, 10 people might chime in on a topic but only a much smaller number have any real deep knowledge of the subject. Lakeside53 is a person to pay attention to. Trust me.

              Here are some details from my build: to keep things as quiet as possible, my RPC sits on a rubber mat. Further, the idler motor has thick rubber "washers" it is mounted on. These are trivial touches, but quieter is easier to live with. Second, my RPC is in a small machinery room attached to the end of my shop which is under my house. Also in that room is my boiler and hot water heater. That room gets noticeably warmed when the RPC is running. In the winter, I take advantage of this by opening the machinery room door to let the heat in. In the summer, I use a small exhaust fan to blow the heat outdoors. Again, these are trivial matters but the end result is I don't have to heat my shop, and that's a big deal. (I'm in the Seattle area which has fairly temperate winters.)

              Another small touch that I continue to appreciate was adding 3 voltmeters showing the leg-to-leg voltages. Here's a not-so-great photo:

              It's very gratifying (and cool) to see all 3 meters reading very close to 240VAC. Means the balancing caps are working.

              If you are curious about the actual elements of my design electrically, lakeside53 already published the schematic above. I did make one change since then - I changed the output fuse block from 30A fuses to a 40A 3-pole breaker. I have several pushbutton stations around my shop. To turn on my RPC I just push the START button momentarily and that's it. The timer relay shuts off the pony motor after long enough for the idler to be up to speed (we chose 2 seconds). Dead easy. Reliable. Simple.

              metalmagpie
              Ok. Well. I'm hard headed, but not that hard headed. Advice here has been overwhelmingly one sided. Ditch the clutch, idle the pony, or stick with caps.

              Roger that.

              I like lakeside's design. I will be paying attention to it. I was planning to draw my own schematic, but with the clutch dropped, well... I may not need.

              We did rubber on Dad's as well. I will have rubber, but I also intend to have it outside, so I don't have to hear it or pay to cool it (AC).

              I love the voltmeters and intend to do the same. Maybe not immediately, as they aren't free and that money will be earmarked for more immediate shop needs, but I will leave wires and room for them for sure.

              Thanks for the post magpie.
              21" Royersford Excelsior CamelBack Drillpress Restoration
              1943 Sidney 16x54 Lathe Restoration

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              • #52
                Does/has anyone made a soft start RPC ??
                DZER

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                • #53
                  Dunno about the soft start, but if Lakeside has the experience then I'd go along with that.
                  25 miles north of Buffalo NY, USA

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                  • #54
                    After Spring Seeding is done I will setup a Idler Motor with Pony Motor equipped with centrifugal clutch just for kicks and curiosity.I will post my results and call It
                    Myth Buster lol!

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