80-100 bell set screw question

[MrDude_1]

so this may be a dumb question, but I figured i would ask before I tear my motor apart.

While checking my motor before its final install, I found the bell set screws to be snug, but not tight. I tightened them, but now I worry... right above them is a flat spot.
are the set screws supposed to be on that spot, or is that for when you put something else on the shaft?
This is what it looks like now:

 

[1000w]

I have disassembled lots of RC motors and in my experience that flat is for the grub screw.
What does the other end of the shaft look like, is it flush with the outer bearing or look pushed in?

 

[MrDude_1]

I have disassembled lots of RC motors and in my experience that flat is for the grub screw.
What does the other end of the shaft look like, is it flush with the outer bearing or look pushed in?

the other end is where I am pulling power off of. it looks like its properly located...

So in anycase, I read your post, and I loosened the screws, took the endcap off and pushed the shaft in enough to reach the flats... now I can tell the cap wont fit, theres too big of a gap.
I guess I need to totally remove the shaft (or that bell end at least) and make some flats in the proper place.

 

[Thud]

Iirc, there are 2 flats on that end of the shaft...
You already in one of them, the 2nd one is for the propellor adaptor to lock onto...along with screws on the back plate.

Are you using that end of the shaft? I usualy cut it flush.

 

[Byte]

As thud says, there are 2 flat spots on the shaft. On my 80-100 the exact screw was loose too. Strange thing is the motor worked good though. I think it is a heavy interference fit with some glue maybe, and an extra set screw.

When disassembling the motor, I never got the shaft apart from the orange housing even with the set screw out :lol:


Anyway, just tighten the set screw and everything is fine.

 

[MrDude_1]

Iirc, there are 2 flats on that end of the shaft...
You already in one of them, the 2nd one is for the propellor adaptor to lock onto...along with screws on the back plate.

Are you using that end of the shaft? I usualy cut it flush.

awesome! That is what I was hoping to hear! I was not looking forward to pressing that shaft out. the two can bearings are a very tight fit on the shaft. almost too tight.


I am using a bit of the shaft.. it helps center the impeller/fan on the end. I still plan to cut it shorter, but I want it flush with the impeller, not the motor.

 

[Thud]

That my friend, is a lovely cooling fan.

-is that your handy work on the design?
-your printer?
-how long was the print time?
-are you happy with the results....& confident of the durability. (I see a little separation in the photo's)

1 or 2 wraps of some carbon tow or any high performance filament will make it bomb proof.(Centrifugally speaking- I would spin it at 10K )

If I were going to that level of complexity, I would take the last step & add an air-foil to the blade section & gain the last % points of efficiency out of that bit_H :wink:

next Q: is that the 80-100 I linked you to? looks brand new....(shoulda bought it myself 8) )

Thanks for sharing.

 

[MrDude_1]

That my friend, is a lovely cooling fan.

-is that your handy work on the design?
-your printer?
-how long was the print time?
-are you happy with the results....& confident of the durability. (I see a little separation in the photo's)

I wish I could say I made it, but I actually found it on here.
http://endless-sphere.com/forums/viewtopic.php?f=30&t=62990

The only thing I did is talk a friend into printing it for me and mailing it to me. Took him a couple hours to print at 100% fill. We used no standoffs, so there was some "hair" on the bridge across, but it cleaned up perfectly. The thing is solid plastic so it feels pretty beefy. I have already spun it to whatever RPM my motor hits at 72 volts in open air. as a side note, you were correct about the motor reaching a threashold and suddenly heating up fast. once it gets past a certain speed it really heats up "for no reason"...

1 or 2 wraps of some carbon tow or any high performance filament will make it bomb proof.(Centrifugally speaking- I would spin it at 10K )
If I were going to that level of complexity, I would take the last step & add an air-foil to the blade section & gain the last % points of efficiency out of that bit_H :wink:

I actually have some CF sock/tube here I thought I might have to lay over it... but its so solid that I dont think it needs it. It not only sits flush on the motor, but it hugs the can, both to stop air leaks and to hold itself steady. I am not expecting problems since it works at a higher speed than I'll use it at...
I DO wish it had an airfoil blade... but I decided to just print it as I found it first, then tweak if needed. I think the person that made it had a great concept, but it could use some refinement...
I actually went for a "forward" blade direction instead of reverse. My theory is that since a forward blade can create a greater pressure differential (at the cost of less volume) it will pull air harder around the mostly packed stator. The volume is kind of made up for, just do to its sheer size. they're big blades.
another benefit to running forward swept? absolutely silent. run it the other direction and its a little whiny. both directions are quieter than straight blades though.

next Q: is that the 80-100 I linked you to? looks brand new....(shoulda bought it myself 8) )

Thanks for sharing.

Yes it is! and thanks for pointing me to it. I put 90% of the scratches you see on it. lol.
still working on the 80-85 you sent me though.. I managed to finally get one half of a wrap(2 poles) done tight... then I broke the wire. I think it broke from stress of being wound/unwound 4 times, but I prefer to think I am just that strong. I am getting the hand of it, but damn is it hard work.

While im at it, thanks for sharing all the other info.. I think I referenced your prior work more than anything else to get it spinning... from how it goes together and comes apart, to winding, to power figures, to controller settings, I would read.. find the info I needed and the username usually read 'Thud' :lol: