traction versus boat motor.

Discussion in 'Hybrid' started by Mick@itc, Apr 14, 2012.

  1. Mick@itc
    Joined: Jan 2011
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    Mick@itc Junior Member

    well i found what i thought was the perfect electric motor for a boat by reading lots and lots of car conversion forums. The number of people out there doing DIY conversions of cars to electric powered cars is amazing. Anyway I eventually found this blog where a person had reviewed stacks and stacks of motors for car conversions and decided a particular one was the best. I was given the direct contacts for the owner/inventor of this motor and asked him the question regarding a replacement for the specified diesel motor. To my amazement he told me that motors built for traction (which his one obviously was) were not usable in boats. It is not a corrosion issue as these motors are exposed to salty water coming into the engine bay after salt road de-icing. One of the factors that is different is the fact that the force in traction is torsion and shaft bearing. On a boat the shaft transfers push into the motor itself. Had not thought of that.
    So can anyone else thing of what other properties would be required by a boat electric motor? Torque and shaft power are givens, along with corrosion resistance. Anyone else think of anything?

  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    You need a double thrust bearing in the shaft so the thrust doesn't get transferred to the motor. They are standard equipment and you can get it from a bearing supply.
    1 person likes this.
  3. Steve W
    Joined: Jul 2004
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    Steve W Senior Member

    Gonzo has it right,you just need to transfer the thrust to the hull and let the motor shaft just rotate.

  4. Mick@itc
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    Mick@itc Junior Member

    Kws are kws

    So apart form thrust bearings there is no other reason a traction motor is different to a boat motor...torque is torque, kws of power are kws of power!! A wheel spinning on a road is the same as a prop in the water! I think!!:?:
  5. PAR
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    PAR Yacht Designer/Builder

    A wheel spinning on the road is not the same as a prop spinning on a boat, though you can probably make some modifications to your motor to make it serviceable in the marine environment. There are other considerations for a marine environment, besides the thrust bearing issue.
  6. mydauphin
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    mydauphin Senior Member

    A motor on a boat is on full load all the time, there is no coasting. The power drain on your batteries will be much more than on a fork lift. You also need to worry about heat dissipation. But that is easy to solve, water cooling jacket.

    Your batteries are your limiting factor. Big motors need a lot of juice. Don't spend a lot of money to fins out it will only run an hour before your drifting powerless.

  7. Mick@itc
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    Mick@itc Junior Member

    Can you elaborate??

    Actually, let me try to summaries...regarding purely the motor component. The key differences are...
    - the motor is under torque load continuously while power operating;
    - the motor requires a double thrust bearing to take the forward/aft loadings;
    - the motor will require additional cooling due to the combination of continuos loading and lack of airflow compared to auto installation;

    Anything else??

    Thanks guys

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  1. Mick@itc
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