Electronics > Projects, Designs, and Technical Stuff
Making an induction motor go crazy fast.
<< < (4/10) > >>
Circlotron:
No plastic fan. The internal fan is part of the cast aluminium end rings on the rotor.
Ian.M:

--- Quote from: Circlotron on August 30, 2019, 03:57:14 am ---
Rotor is 70mm diameter and 60mm long. Shaft is 14mm. Out of an automatic sliding door like this one -> https://youtu.be/nKdHCjAEKuI?t=61

--- End quote ---
I've recalculated for your actual rotor - at 16800 RPM that's 138 MPH, 11000 g, 1650 J

Once you've got containment, it needs more volts and more Hz.  >:D
Berni:
That's one fast motor alright.

Tho i don't think this is quite as dangerous as it sounds from the hefty number of Joules in the thing. The rotors on induction motors are typically solid chunks of iron and aluminum and the fan is typically part of the same casting. So the thing is very strong. And if it does start to desegregate it will hit the strong laminated iron stator.

So if you do get it spinning past critical failure speed it most likely will not explode or send shrapnel at high speed. Tho as the failed rotor grinds to an incredibly loud halt against the stator or failed bearings the rotational inertia has to go somewhere so the whole motor will likely fly off and roll across the room, this is not something you want to get in the way of.
Ian.M:
I wonder about how close to cold flowing the squirrel cage is.  It cant be a very hard alloy as the resistance would be too high, and with over 100 N of force radially outwards on each gramme of rotor bar, if the channels the bars run in don't support the bars well enough, bad things will happen. 


--- Quote from: Berni on August 30, 2019, 08:27:58 am ---Tho as the failed rotor grinds to an incredibly loud halt against the stator or failed bearings the rotational inertia has to go somewhere so the whole motor will likely fly off and roll across the room, this is not something you want to get in the way of.

--- End quote ---
Yes.  The whole motor taking off at a few thousand RPM, and pinballing off the test equipment, walls and other objects in the room could be a little too exciting for most people.  That's an expensive brown trousers moment even if you escape serious injury, and may result in your significant other banning your hobby!

Running any high speed motor larger than you can comfortably close your hand round loose on the bench is never a good idea.  It only takes a couple of minutes to bolt or strap a motor down to something wide and heavy enough to stay put (more or less) to minimise the possible excitement.
max_torque:
Generally the bearings will be well goosed before the rotor lets go!

(as most induction motors have v cheap bearings in them)
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod