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post #43 of Old 01-04-2019
texlan
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Re: Electric Conversion log for Kahleesea

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The motor I'm going with, the Motenergy 1115, weighs 35 lbs. I could run it as a direct drive, but since it's only going to turn at about 1000rpm, it won't turn fast enough to cool itself and I could easily burn it out. So I'll put a gear reducer on it so it runs about 4000 at hull speed, keeping itself cool while giving me what I need. I could go with a water cooled model, but that adds more complexity that I would like for this project. Once the system's finished I can always retrofit if I find that cooling is an issue. The motor comes with a built in temperature sensor so I can monitor it via the motor controller.
Howdy Captain. Being in the middle of an Ericson 29 refit (rebuild?) that includes going to an electric prime mover (same one you are looking at!) I'm on your side. However --

I caution you to test your new motor/controller at your intended voltage before you buy/lock yourself into a gear ratio. Brushless motor speed is based on its KV rating (rpm per volt). You're expecting/designing for 96+v rpm from a 48v power bank, from what I gathered reading the thread. You will not see the rpm you are expecting.

So fire up your no load motor at 48v, measure the RPM (i believe the clearview will tell you the RPM..) knock about 5-10% off of that for load, then figure out your gear ratio.

Thunderstruck recommends a 2-1 gear reduction for a reason with controllers defaulted to 48v.



Sean
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