low KV motor 1.5KW, cheap and waterproof

crossbreak

crossbreak

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I'm searching for a motor that has low KV in the range of 30-50 and is waterproof and reliable. It should fit between the BB so the width should not be greater than 67mm. I found this wind generator:

459612197_772.JPG

459612733_510.jpg

source:
http://www.aliexpress.com/product-f...ermanent-Magnet-AC-Generator-wholesalers.html

KV rating : KV37.5 (12volt version) and KV18.75 (24volt version)
weight: 3.5kg
protection class: IP54 (info from other supplier)
continuous current: 25amps (calculated from wattage figures)
maximum current: 30amps
no halls since this is a generator :(
the price is $185+$80 shipping

At 50Volts (13s Lipo) it should handle 1500W input power and runs at only 1875rpm. What do you think? How will this thing perform? I'd like to have sth. similar to the GNG drive but with lower rpm and almost silent.
 
Looks like you've got sth. similar to the 24Volt version of this one, they both have 12 poles and around KV18?
Hey Miles, you posted in your cross reverence threat:
Ke = 17 V/kRPM
Click to expand...
Edit: that would be around 59KV if I calculated right. Looks like has a different wind.
 
Similar concoction. Mine is wound for 69 rpm/V. Ford alternator core. Both bearings on the same side. Probably the same rotor source.

Edit: Sorry, you're right, I meant 59 rpm/V
 
crossbreak said:
At 50Volts (13s Lipo) it should handle 1500W input power and runs at only 1875rpm. What do you think? How will this thing perform? I'd like to have sth. similar to the GNG drive but with lower rpm and almost silent.
Click to expand...
At that speed, it should cope with 1kW continuous output without breaking a sweat.

It would avoid the wide ratio first stage reduction problems of the GNG drive, too.....

How about we design an Endless Sphere mid-drive kit, using this motor?
 
cool idea, i'm in! i could design a mount, similar to the GNG or Tongxin mount for the BB on both sides. I'd like to use #25 chain for the first reduction for simplicity. What are your thoughts about the primary reduction? i guess it has to cope with some torque.
 
Isn't this the infamous "Randy Motor", Miles? Looks very similar to it, but yours is the only one I've actually seen used.
 
the KV of 37.5 was calculated from the data on the aliexpress page. they state it has 450rpm at 12Volts. But I guess thats loaded rpm and generated volts. the KV would be higher then, I guess it will be around 1.4 times the KV I calculated, that would be about 53KV. I guess we can only answer this if I buy it.
 
Jeremy Harris said:
Isn't this the infamous "Randy Motor", Miles? Looks very similar to it, but yours is the only one I've actually seen used.
Click to expand...
Pretty much, yes. I think SouthWestern Windpower used the same rotor as these have when they made the "Randy" motors. The stator core is slightly different.
 
crossbreak said:
the KV of 37.5 was calculated from the data on the aliexpress page. they state it has 450rpm at 12Volts. But I guess thats loaded rpm and generated volts. the KV would be higher then, I guess it will be around 1.4 times the KV I calculated, that would be about 53KV. I guess we can only answer this if I buy it.
Click to expand...
Any Kv between 40 and 70 would be ok, I guess..
 
O ring around the case join?
Click to expand...

If it's really IP54 there should not there be a stock one :?:

It would be good to find out the thickness of the laminations that they've used for the core before we get too excited....
Click to expand...

Maybe we can find some more pics and count ;)


[loadly thinking ]
at 30 amps, and KV of 37.5 it would have
Ke=26,67volt/krpm ant Kt of 0.2667Nm/amp, thats about 8Nm @30amps.

If we use a #25 sprocket on the motor the max chain pull should be around 500N ( 1/6 of the 3kN breaking strength of this chain).
This would mean we should use a sprocket with 8Nm/500N= 16mm operative radius. That would be a 14T #25 sprocket on the motor.
 
Yup.

http://www.wxnaier.com/productShow.asp?ID=795

Slightly less garbled specs than on Ali

Also:
http://wxnaier.en.alibaba.com/product/456466429-210758104/400w_24v_output_permanent_magnet_generator.html
 
Maybe we should email them about the stator lamination thickness and hopefully get an answer on Monday or Tuesday.

Edit: we should also ask for the no-load voltage at 450rpm. Are you willing to write them miles? your English is definitely better then mine, but in fact that doesn't even matter :lol:

:?: anithing else i should ask for :?:
 
I wonder what the maximum rpm is? If the magnets are only held on with glue, they will tend to fly off at high speed. They may possibly have bolts in addition to glue, which would be a good thing. The rotor core could be drilled out to reduce weight. It doesn't need to be solid.

I love the dimensions in the first drawing. 6 feet diameter is pretty big.
 
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