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fgamache
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Joined: 09/01/2024
Location: Canada
Posts: 3

Posted: 05:59pm 13 Jan 2024

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Hi!

TLDR: Is there a direction a SmartDrive rotor should turn? Does it matter?

Longer version:

Ok so I have an off-grid solar setup which is great between March and November but the other 3 months of the year are pretty cloudy/rainy in the Pacific Northwest and with the short days we need to top-up with a generator.

I do have a seasonal stream that gives me 5-10L/s @ 15m head so I am *attempting* to cobble together a basic hydro rig to see if I can actually produce anything useable.

Through the amazing resources available on thebackshed and others I have gathered the needed parts and bobbles and am rewiring the SmartDrive stator to suit my site and system (3P4S with provisions for either start or delta). I bought what looks like a pretty decent pelton wheel on eBay and have 100m of 75mm hose to go from the source (a culvert, really...) to my turbine.

Next I'll assemble the turbine & rotor together reusing the shaft of the washing mashine to attach the pelton to. Does it make a difference which direction the rotor turns? IE I can attach the pelton so the rotor turns clockwise or reverse - does it matter? I can't seem to see anybody specifying this in their videos so I'm guessing either works but not sure...

I guess my question illustrates my lack of undestanding of the fundamentals of permanent magnet motors but here we are lol.
Edited 2024-01-14 04:38 by fgamache

mab1
Senior Member

Joined: 10/02/2015
Location: United Kingdom
Posts: 152

Posted: 07:26pm 13 Jan 2024

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No it shouldn't matter which way it turns, unless you're using the 3 phase power directly, and even then it simply reverses the phase sequence which is easy to switch back electrically.

If you're rectifying the output to charge batteries it won't make any difference.

fgamache
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Joined: 09/01/2024
Location: Canada
Posts: 3

Posted: 07:59pm 13 Jan 2024

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Super, thanks for the response.

Yes, I will be rectifying to DC.

Godoh
Guru

Joined: 26/09/2020
Location: Australia
Posts: 378

Posted: 08:19pm 13 Jan 2024

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Smart drive motors as generators are good stuff, they do tend to take a fair bit of energy to overcome the cogging effect from the permanent magnet rotors.
This can be reduced by spacing the rotor out a bit to limit the amount of magnet under the stator pole pieces.
I had a small creek with a 10 metre head, 50mm pipe but it was not capable of turning a smartdrive.
I used a car alternator, then adjusted the rotor current with a resistor to get maximuim output.
That worked well, as I only had a short run from the creek to my batteries.
Good luck with the project, I hope it works well
Pete

fgamache
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Joined: 09/01/2024
Location: Canada
Posts: 3

Posted: 03:48pm 14 Jan 2024

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This one is a 36 pole stator which, as I understand, has much less cogging. I also considered the great calculators on powerspout.com to determine the best wiring configuration for my site, and they do cover spacing the rotor out and star vs delta as things that can all help getting the rotor moving...

We'll see if the theories apply in practice!

mab1
Senior Member

Joined: 10/02/2015
Location: United Kingdom
Posts: 152

Posted: 04:55pm 14 Jan 2024

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I don't consider cogging to be a big issue with hydro generators: one of mine is quite coggy, and if i want to run it at <60w then i might have to give it a push to start, but it's not like a wind genny where self starting is important - the hydro only has to start when I'm there turning the water on.

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