开云体育

On 2/4/2024 11:06 PM, Chris Albertson wrote:
> brushless motors are combatted externally, usually with software controller 6 MOSFET switches.? These motors produce the highest torque at zero RPM.
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> Note that a common stapler motor is also a kind of brushless motor that is controlled as said above and it also has the most torque at zero RPM.
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> A few things have changed in the last decade or so to allow motors to become very powerfull and compact
> 1) Rare Earth magnets.? These are incredibly powerful and tiny.
> 2) MOSFETS with on resistance of only a few milli-Ohms.
> 3) micro controlers that sell for about $1.
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> So now we have battery operated drills that have enough torque to almost break your wrist and bikes.? ? ? (BTW take a good look at ebike motors and e-skateboard motors.)
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>> On Feb 4, 2024, at 11:08?AM, Jay Fougere <groupsio@...> wrote:
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>> You can get those sewing machine motors on Amazon for quite a bit less than that ebay listing.
>>
>> (Note: Not Prime... shipping is $25 on the one listed but you can find them for less shipping - they always land around $100 total though)
>>
>> I have one now that I am fitting on one of my X2 mini-mills - if it works as well as I expect the 2nd mill will get one too :)
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>> I don't know others, but the one I linked uses standard Molex 5557 (Computer PCIe power) connectors if you want to make custom wiring or use attachments not included in the kit.
>>
>> Earlier in this thread someone mentioned the RPM ratings of this motor and claimed the higher RPM is due to losing power at lower RPM, implying these are not a good choice for many applications - that is not true with these motors. These are basically 3-phase motors and the way they change speed is *not* by changing/pulsing voltage. These phase-shift to change speed so that you can keep almost constant torque independent of rotational speed.
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>> Just my $0.02 ;)
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>> -Jay
>>
>> On 2/4/24 13:02, chrisser via wrote:
>>> Went down the rabbit hole on these sewing machine motors.
>>>
>>> I'm liking them.
>>>
>>> I found some sites that show how to add a potentiometer to create a speed control dial to replace the hall effect sensor used in the treadle control.? Some conflicting info, but I think I have a couple of combinations of pots and resistors that should work - it's pushing the limits of my electronic competence.
>>>
>>> Also found a couple of ways around the clunky reverse control, not that I expect to need it on the drill press, but if I can get the RPMs down low enough, it might be nice to have it as an option for tapping, although I've always preferred being able to feel with a hand tap, even if chucked in the drill press to hold vertical.? Since the motor is three-phase, just swapping two phases and one associated hall effect sensor in the motor will reverse, and there are inexpensive 4-pole drum switches on ebay that are rated to the voltage/current without spending too much cash.? I even found an emergency switch with three poles that would cut the three phases to the motor.
>>>
>>> Think I'm going to pick one up in a few weeks and give it a try.? May get another for the 7x lathe - I'm guessing I could sell the original controller board and motor on ebay to close to what the sewing machine motor would cost and gain a little extra power and not have to worry about the control board losing it's smoke sometime down the road.
>>>
>>> On Saturday, February 3rd, 2024 at 5:19 PM, Ralph Hulslander <rhulslander@...> <mailto:rhulslander@...> wrote:
>>>> You might want to consider using a 110 volt 3/4 hp brushless motor off ebay <>.
>>>>
>>>> I use them on my 8520 mill and on my 16" Delta band saw. I also had one on 12x36 lathe.
>>>>
>>>> There are other brushless <> explore.
>>>>
>>>> Ralph
>>>>
>>>> On Sat, Feb 3, 2024 at 4:26?PM chrisser via <> <chris.kucia=[email protected] <mailto:[email protected]>> wrote:
>>>>> This may be a bit off topic, but I would guess it is applicable for someone wanting to re-motor their lathe.
>>>>>
>>>>> Have one of those 80s Taiwanese drill presses (Cummins Mack). Motor HP isn't listed but it's probably 1/2 or 3/4HP. 100vac single phase.
>>>>>
>>>>>
>>>>> Kind of sick of changing belts and thought one of those variable speed motor conversions would be helpful. I read a lot about how inexpensive these are, but I'm just not seeing it.
>>>>>
>>>>>
>>>>> I probably have 10 motors lying around the shop, all 110VAC single phase of various sizes and RPMs. Looked around for something in the 3/4-1hp range in a 3phase motor on Craigslist, Marketplace, ebay, surplus dealers - they don't seem cheap to me. To get something in the right RPM range (~1700) and standard voltage is at least $100 if not closer to $200. Add another $100-200 for a VFD and that's not my definition of inexpensive. New motors are double that.
>>>>>
>>>>>
>>>>> Read about using a treadmill motor, but word seems to have gotten around about those. They're in the same price range as the 3phase motors, although the controllers seem cheaper. Buying a couple of random treadmills to hope and get the right size motor that's useable seems like a big PITA and here in rural America, getting rid of the rest of the treadmill without the motor isn't exactly easy or cheap.
>>>>>
>>>>> Am I looking at the wrong things, or am I just a cheapskate? Maybe both.
>>>>>
>>>>> I've read it's possible to use a VFD on a single phase motor by bypassing the start capacitor using a start switch to energize it. Having trouble finding good info on what VFD to use. I don't really think I need the drill press to reverse, which is one of the downsides of single phase. Would this be a solution to use the original motor or one of the spares I have lying around?
>>>>>
>>>>>
>> --
>> -Jay Fougere
>>
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