I didn't expect it either and I was amazed. All other motors I've opened were hard to disassemble, with pressed bearings.
BTW
Out of topic:
"Induction motor", is it the official english language name ?
In France we say " asynchronous".
Such a motor spins at a speed near the stator windings speed ( from 50 Hz ), but slips. Slipping makes the torque.
OTOH the "synchronous" motor runs at exactly the stator windings speed. Some offset makes the torque.
Out of topic:
"Induction motor", is it the official english language name ?
In France we say " asynchronous".
Such a motor spins at a speed near the stator windings speed ( from 50 Hz ), but slips. Slipping makes the torque.
OTOH the "synchronous" motor runs at exactly the stator windings speed. Some offset makes the torque.
I learned induction back in the early 70's, but both terms are certainly correct for this type of motor.
I've only used 100 hp 480 volt 3 phase units of this exact type. Nowadays, I have been using much smaller brushless 3 phase things, half horse give or take, but they have magnetic rotors and act synchronous, including encoder feedback.
I would not have thought of an asynchronous unit for a coil winder, but I suppose given sufficient capacity, the motor would slip very little with light load.
My last toroid winder used steppers. It sounds really cool in operation.
Jn
I've only used 100 hp 480 volt 3 phase units of this exact type. Nowadays, I have been using much smaller brushless 3 phase things, half horse give or take, but they have magnetic rotors and act synchronous, including encoder feedback.
I would not have thought of an asynchronous unit for a coil winder, but I suppose given sufficient capacity, the motor would slip very little with light load.
My last toroid winder used steppers. It sounds really cool in operation.
Jn
Ah, previously you said it turned perfectly. I assume that was without belt, and with belt hand turned it knocked.
That was a good catch. Question is, why is it changing? The only way the case bearing bore can open up is subjecting the unit to very cold temps such that the aluminum is stretched, but that would have to be really really cold and the bored hole had issues.
One trick for a slightly loose bearing fit is to take a large ball bearing (a single ball an inch or two in diameter), put it on the opening (motor apart of course), with a large backing piece, and smack it with a hammer. That peens the opening slightly closed (.001 or .002 mils, 80 microns), and the bearing is tighter.
If the Manu did that, it will leave the factory floor working perfectly, but there is very little aluminum holding the bearing centered. That could explain the eventual loosening.
I assume there were no spot peens in the aluminum surrounding the bearing, that is also used to tighten fits but again, not so much long term strength. That method would be visible, the ball bearing method may not be visible.
Again, great detective work.
Jn
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An asynchronous motor is an induction motor (it operates via induction), whether it has a wound rotor, solid rotor, or squirrel cage.
Most synchronous machines are started as induction, asynchronously, until slip speed is achieved, after which the rotor is excited to bring the rotor into synchronism.
It would make a poor choice for a winder.
You want DC or externally commutated DC (BLDC) for that duty.
Those funny "3 phase permanent magnet rotors", are actually asynchronous....in their simplest form, and switched/commutated DC, not AC. (it's only the Hall effect sensors and feedback to the controller, that phases forward the drive to sync it..)
My heath Robinson Traffo winder is a 24V 60W DC motor with 90degreee drive (60W or so) for full load speed of 90rpm
Most synchronous machines are started as induction, asynchronously, until slip speed is achieved, after which the rotor is excited to bring the rotor into synchronism.
It would make a poor choice for a winder.
You want DC or externally commutated DC (BLDC) for that duty.
Those funny "3 phase permanent magnet rotors", are actually asynchronous....in their simplest form, and switched/commutated DC, not AC. (it's only the Hall effect sensors and feedback to the controller, that phases forward the drive to sync it..)
My heath Robinson Traffo winder is a 24V 60W DC motor with 90degreee drive (60W or so) for full load speed of 90rpm
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All the ones I use are synchronous. Stop the stepping pulse or velocity signal, they lock into position. That's why the magnetic rotor, like your example but with the rotor permanently excited. They act just like a stepper in that regard. With the encoder active in the PID loop, the three phase and steppers can hard lock to within 2 encoder counts static, and I push for 25 counts in motion, system dependent of course.
There are quite a few different designs out there, so we are not actually disagreeing.
All of my drives, 3 phase and stepper, have bipolar PWM outputs, so can produce two or three phase drive. In addition, the steppers can be microstepped down to 512 microsteps for smooth motion.
My PID loop also cycles every 400 uSec, so will dither the motor down to 1 or 2 counts. If the load is too light, it can introduce a dithering vibration on the load, always a trade off.
For extreme magnetic measurement systems however, the PWM drive can introduce hash into nanovoltmeters. I long for the pure analog drives.
Jn
There are quite a few different designs out there, so we are not actually disagreeing.
All of my drives, 3 phase and stepper, have bipolar PWM outputs, so can produce two or three phase drive. In addition, the steppers can be microstepped down to 512 microsteps for smooth motion.
My PID loop also cycles every 400 uSec, so will dither the motor down to 1 or 2 counts. If the load is too light, it can introduce a dithering vibration on the load, always a trade off.
For extreme magnetic measurement systems however, the PWM drive can introduce hash into nanovoltmeters. I long for the pure analog drives.
Jn
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Excellent news guys! Knocking has been gone! Cheers!
P.S. I was expected to assemble it yesterday, but I'm into a hangover.
Would it make sense that my first workshop went sometimes into sub-zero temperatures during winter times? Probably -10C, not more.
P.S. I was expected to assemble it yesterday, but I'm into a hangover.
Would it make sense that my first workshop went sometimes into sub-zero temperatures during winter times? Probably -10C, not more.
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You let your winding machine sit in a room that goes to -10C???
Oh the humanity of it!!!!!
I would not rule it out as the cause. Making things that have to work a few degrees above absolute zero tends to get one to focus on what changes occur due to the temperature drop, something many manufacturers do not consider.
Jn
Ps.. for me, the best aspect of this forum is the brainstorming weird problems. Putting multiple people together to try to figure weird things is great.
Oh the humanity of it!!!!!
I would not rule it out as the cause. Making things that have to work a few degrees above absolute zero tends to get one to focus on what changes occur due to the temperature drop, something many manufacturers do not consider.
Jn
Ps.. for me, the best aspect of this forum is the brainstorming weird problems. Putting multiple people together to try to figure weird things is great.
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Excellent news, thanks
I´ve already called a friend of mine to bring over some
Loctite Bearing Seal, that he has stashed somewhere in his workshop. Will see what happens 🙂
Who would expect? Seriously, an industrial looking grade motor? What if it was shipped during winter time, sitting in a storage container.
I would always preheat the room before starting winding, mainly because of the grease becoming too thick and the belt too stiff at low temperatures. But this? Bearing housings?
This is really the coolest aspect of this forum - lots of different minds and expertise together in a forum package that can communicate in a friendly way. It's nice to know we can be helpful to each other!
Good luck, Boydk!
BAbout this issue of a bearing at very low temperature we need experts used to the Artic winter temperatures.
Siberia, Canada, Scandinavia.
BTW
I have been in Sofia and visited mountains nearby at winter time, that was dann cold, well below -10°C.
Siberia, Canada, Scandinavia.
BTW
I have been in Sofia and visited mountains nearby at winter time, that was dann cold, well below -10°C.
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