Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

RPM to Pulley Question Please Help Thanks

  1. Feb 23, 2012 #1
    RPM to Pulley Question Please Help Thanks!!

    I have a log splitter that uses a gas engine 3600 RPM the drive pulley is 1.5"OD diameter and the driven pulley is 18.25" diameter (Super Splitter is the brand name) So from what i calculated was the driven pulley weighs in at 75lbs and spins at about 295 RPM's.

    Now to my question: They sell these splitters with an electric motor, So my grandfather gave me a 1 hp electric motor that rotates at 1740 RPM. If i put on a drive pulley with a 3"OD will i have basically the same outcome? Im calculation 286 RPM.

    This splitter uses the weight of the flywheel to throw the ram forward. And i would like to convert to Electric because it is alot quiter for my neighbors, they already have to hear my chainsaws screaming! Thanks Everyone!!!!
     
  2. jcsd
  3. Feb 23, 2012 #2
    Re: RPM to Pulley Question Please Help Thanks!!

    We need to know the power rating of the gasoline engine you are replacing.
    After a quick Google, all the electrically powered splitters I looked at have 1.75 HP motors, and the smallest gasoline powered models run about 3.5 HP.
    You will probably need to change the drive ratio quite a bit to get sufficient torque from your 1 HP motor. The splitter will operate much slower, and almost certainly at reduced capacity (smaller logs).
     
  4. Feb 23, 2012 #3
    Re: RPM to Pulley Question Please Help Thanks!!

    The splitter that i have has ZERO hydraulics once again the brand name is Super Splitter ZERO hydraulics it uses to flywheels. They sell this SUPER SPLITTER with a 1 hp and a 1.5hp motor the cycle time is 3 seconds its not your everyday log splitter the engine it has right now is 5.5 hp but thats not the issue i am talking about the RPM's. All i need to know is will the big flywheels still be spinning the same from what i calculated.
     
  5. Feb 23, 2012 #4

    OldEngr63

    User Avatar
    Gold Member

    Re: RPM to Pulley Question Please Help Thanks!!

    Your calculation is in the right ball park (I have not check the numbers with my calculator). The product N*r is proportional the belt speed coming off the engine or motor pulley in either case. So 3600*1.5 is not too different from 1740*3.0; we double one factor and halve the other.

    As mentioned above, the cycle time may be unsatisfactorily slow; it may take a long time to recover flywheel speed, but it should recover to almost the same level and hence same kinetic energy content.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: RPM to Pulley Question Please Help Thanks
  1. 1 RPM Motor help. (Replies: 18)

Loading...