Friday, May 28, 2021

Re: [electricboats] Silly question - powering with a 120V AC motor?

That looks great.  I like the way you used the I-beam section in the assembly along with the angles to give you pitch and yaw adjustment.    Well done.   I was going to use a C-channel for my mounting plate but it was not wide enough to accommodate the large belt pulley I needed for my 3:1 ratio.  The big pulley is 60 tooth and relatively heavy (16lbs/7kg) and is a bit of a flywheel. 

I'd like to see more of your bearing housing fabrication.   I used a 5207 double angular contact bearing and a UCF205-16 flange mount as a pilot bearing on the output shaft of my reduction gear.   I used a rubber sealed 5207 and made a housing from aluminum.  Not as robust as steel but ZF marine transmissions are aluminum and have to hold similar bearings to take similar loads so I am giving it a try. 

I have a soft mount by having my mounting flanges sit on rubber blocks that sandwich the fiberglass beds of the boat.  The equivalent place would be under your unistrut rails. 

I am at about the same state in my assembly.  Maybe a couple weeks from going in the water.   I am about to machine the output shaft of my reduction gear unit. 

I am sure you are correct about re-aligning in the water. 


Dan Pfeiffer

 

On 2021-05-26 12:13 pm, julie Lynch wrote:

Hi. I am in the process of building the suggested system.
 24v of leisure batteries 70Ah, 
24v to 230v a.c. inverter, 
230v single to 230v 3 phase variable frequency drive 
and standard 2.2kw 3 phase motor. 
It is going into a Halcyon 23 sailing boat. 84lb thrust, 24v (Bison?) outboard, approx. 1kw as second auxiliary. Found it a bit weak against a headwind on a previous boat, 19ft.
Moored on a swinging mooring in a sparsely populated bay in West Cork, Ireland so very little motoring intended (minutes) so I can absorb the losses of all the electrical conversions. I have a backup so I can accept the increased risk of failure of a component. Cheap chinese components all. Nothing marine rated.
I wouldn't recommend this to anyone who was intending travelling too far or at all for a primary propulsion system. 
I have milled the motor mount to take a more proven bldc motor if I want to down the line.
I am running a 3 to 1 timing belt reduction to the 2 blade prop that was on the boat. I think it's 12d x 10p inches.
Original 3/4" bronze shaft to homemade bearing housing. 5206 double angular contact bearing for thrust and 6206 to take radial belt load. Spaced apart for radial stiffness. Probably should be using stainless bearings. Next year maybe.
Runs fine on the bench. Won't be in water for another month. I'll document and post it if it is still a success by September. 
Recharge via 270w solar.
Backup power is by Briggs and Stratton 3.5hp former lawnmower and 24v lorry alternator.
Worries:
Motor and bearing assembly is mounted hard on to unistrut rails on stringers. No flexible mounts.
Packing gland is hard mounted on stern tube. Essentially acts as a mid shaft bearing. Alignment has to be perfect! I think I may have to align the motor again when boat is floating.
Don't try this at home, kids.
Yet.
 
Anthony
 

On Wed 26 May 2021, 3:21 AM john via groups.io <oak_box=yahoo.com@groups.io> wrote:
 
 
This is probably a really silly question, but....
 
Is it possible to find a 120V AC motor that can be speed controlled (and maybe even reversed??) for at least a proof of concept on a boat?
 
For those of us that prefer electric motors to gas or diesel engines, but are challenged by the investment of a huge battery bank, wouldn't it be cool if we could run an AC motor off an inverter from whatever battery bank we have handy, and use a generator to supplement - or just run off the generator entirely at first?
 
We've discussed the efficiency gain of running off a higher voltage / lower current.
I'm guessing that there just isn't a suitable way to control and/or reverse an AC motor??
 
John
 

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