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wierdscience
01-28-2017, 06:02 PM
From time to time I have needed a smallish single phase motor in the 1/4-1/3 hp range,but something smaller than the usual 56 or even 48 frame motor.The answer was the ubiquitous Chinese water pump,$35 delivered.

http://img.photobucket.com/albums/0903/wierdscience/Motor%20grinder%20005_zps35xahgjo.jpg (http://smg.photobucket.com/user/wierdscience/media/Motor%20grinder%20005_zps35xahgjo.jpg.html)

The one to get is the basket type,where the pump section is attached by three stand off which are cast into the motor end bell.Three screws to remove the pump inlet,pop the impeller off and then void the warranty with a grinder and a zip wheel.

http://img.photobucket.com/albums/0903/wierdscience/Motor%20grinder%20006_zpsxx7nzafl.jpg (http://smg.photobucket.com/user/wierdscience/media/Motor%20grinder%20006_zpsxx7nzafl.jpg.html)

Little cleanup with a flap wheel and presto,a small motor with a 12mm keyed shaft.They claim it's 1/2 hp @ 3400 rpm,which I don't really believe,but they have been sufficient to replace the motor on a planer knife grinder and this one will be the basis of a small radial fin blower.

EddyCurr
01-28-2017, 06:09 PM
Neat.

Plus: that pump will come in handy for something, too.

metalmagpie
01-28-2017, 07:52 PM
I not only needed a physically small motor, but I wanted to be able to speed control it. I used the 3 phase motor off of a coolant pump from some machine tool. I had no requirement for a rigid base.

metalmagpie

boslab
01-28-2017, 08:13 PM
Aparently an old alternator makes a tidy small motor, there's a YouTube relating to it, or using alternators as motors, never tried but looks ok, 3 phase.
I have a few scrap pressure washers I was going to cannibalise for motors, they leak from every plastic connector.
Mark

wierdscience
01-28-2017, 09:42 PM
Aparently an old alternator makes a tidy small motor, there's a YouTube relating to it, or using alternators as motors, never tried but looks ok, 3 phase.
I have a few scrap pressure washers I was going to cannibalise for motors, they leak from every plastic connector.
Mark

Ha,who knew,this one sounds healthy too:cool:

https://www.youtube.com/watch?v=hghDLkmCcpE

J Tiers
01-28-2017, 09:43 PM
Cheap way to get an "almost C-face" motor. Of course it IS a chinese motor......"as is, where is, with all faults". But could be a reasonable approach, for sure.

Too bad they are 2 pole motors. They would look OK on a mini-Bridgeport head. But for any sensible belt system you'd need a 1200rpm, or, at worst, a 1750 rpm motor.

CCWKen
01-28-2017, 11:23 PM
I repurposed a 1hp pump motor and lawn tractor transaxle when I powered my 3n1 metal shear/bend/roll. It's still running great after 12+ years of pretty heavy use. I didn't bother cutting the pump flange off. I used it for mounting.

http://img.photobucket.com/albums/0903/CCWKen/ToolBox/ShearPressRoll/ComboReinforced-1.jpg

http://img.photobucket.com/albums/0903/CCWKen/ToolBox/ShearPressRoll/ComboPowered-6.jpg

MaxHeadRoom
01-28-2017, 11:44 PM
From time to time I have needed a smallish single phase motor in the 1/4-1/3 hp range,but something smaller than the usual 56 or even 48 frame motor.The answer was the ubiquitous Chinese water pump,$35 delivered.

.

The weak point in these Chinese split-phase motor's are the caps, if it fails, replace with a N.A. made motor run cap.
Max.

Joel
01-29-2017, 12:19 AM
Where did you source that one Wierd, and do you have any experience/opinion regarding reliability?

There have been occasions where I could have put a water pump to use, and if they are worth a damn, $35 makes it cheap enough to have on hand.
I found a similar unit on amazon for $36, but it appears from the reviews that half of them only lasted a very short time.
https://www.amazon.com/Tooluxe-50635-Surface-Agriculture-Nozzle/dp/B00VQF6T6C/ref=sr_1_4?ie=UTF8&qid=1485666524&sr=8-4&keywords=1+2+hp+water+pump

(https://www.amazon.com/Tooluxe-50635-Surface-Agriculture-Nozzle/dp/B00VQF6T6C/ref=sr_1_4?ie=UTF8&qid=1485666524&sr=8-4&keywords=1+2+hp+water+pump)

rcaffin
01-29-2017, 12:29 AM
in these Chinese split-phase motor's are the caps, if it fails, replace with a N.A. made motor run cap.
These caps, in my recent experience, will still be made in China. Specifically,a Kemet motor start cap. (Faston lug fell off the start cap on my old compressor: have too replace.)

Cheers
Roger

PStechPaul
01-29-2017, 12:34 AM
I pulled the 2/3 HP motor off of a rusty shallow well jet pump, and I rewound it to a three phase 8 pole motor for nominal 8 VAC. I made a very crude VFD that ran on a 12 VDC battery. I also worked next door to a HVAC place and often found blowers with various small induction motors by the dumpster. I rewound a couple of them for low voltage three phase, but they could have been repurposed for machine tool use. Very often they were hard to turn because of lack of lubrication but they were easily taken apart and cleaned and lubed, good as new. Mostly they were good brand names like GE, Dayton, Baldor, etc. Junk yards that deal in scrap metal are also good places to get motors from pumps, blowers, fans, and such.

RB211
01-29-2017, 07:48 AM
I pulled the 2/3 HP motor off of a rusty shallow well jet pump, and I rewound it to a three phase 8 pole motor for nominal 8 VAC. I made a very crude VFD that ran on a 12 VDC battery. I also worked next door to a HVAC place and often found blowers with various small induction motors by the dumpster. I rewound a couple of them for low voltage three phase, but they could have been repurposed for machine tool use. Very often they were hard to turn because of lack of lubrication but they were easily taken apart and cleaned and lubed, good as new. Mostly they were good brand names like GE, Dayton, Baldor, etc. Junk yards that deal in scrap metal are also good places to get motors from pumps, blowers, fans, and such.

Hey, a question for you. My R/C airplane, car, quadcopter brushless motors with 3 wires coming out. Are they technically 3 phase ac motors? Never really thought about it, but I wonder if a VFD would drive them? Or Vice versa, the speed controls for them could be used as a small cheap vfd? Granted, it's DC in, but I wonder if the sine waves go negative, making it AC?

Noitoen
01-29-2017, 08:42 AM
RC brushless controllers do transform DC into three phase AC but with square wave. They do control the speed but have difficulty in the start/slow speed range. Usually electric bike/scooter motors/controllers, also brushless 3 phase have better control on the low speed range.

Jaakko Fagerlund
01-29-2017, 11:02 AM
12 mm shaft? Well that's not really common, as usual shaft sizes are 9, 11 and 14 mm in that size category. Means that finding off the shelf legos to attach to it isn't as easy.

MattiJ
01-29-2017, 11:13 AM
12 mm shaft? Well that's not really common, as usual shaft sizes are 9, 11 and 14 mm in that size category. Means that finding off the shelf legos to attach to it isn't as easy.

Straight shaft with 12mm bearings?
Bearings go 10, 12, and 15mm in size so that could explain.

Paul Alciatore
01-29-2017, 11:21 AM
Oh, come on. We are machinists, aren't we. 11 mm plus a 12 mm reamer and ten minutes, max.




12 mm shaft? Well that's not really common, as usual shaft sizes are 9, 11 and 14 mm in that size category. Means that finding off the shelf legos to attach to it isn't as easy.

MaxHeadRoom
01-29-2017, 11:23 AM
in these Chinese split-phase motor's are the caps, if it fails, replace with a N.A. made motor run cap.
These caps, in my recent experience, will still be made in China. Specifically,a Kemet motor start cap. (Faston lug fell off the start cap on my old compressor: have too replace.)

Cheers
Roger

The last batch I bought were CDE (Cornell-Dubilier) and assembled in Mexico.
UL and CSA approved.
Max.

Jaakko Fagerlund
01-29-2017, 02:20 PM
Straight shaft with 12mm bearings?
Bearings go 10, 12, and 15mm in size so that could explain.
You are probably right, as it is built to a price point.

MaxHeadRoom
01-29-2017, 02:20 PM
RC brushless controllers do transform DC into three phase AC but with square wave. They do control the speed but have difficulty in the start/slow speed range. Usually electric bike/scooter motors/controllers, also brushless 3 phase have better control on the low speed range.

AFAIK my experience with RC motors are BLDC not AC, subtle difference, AC means all three winding's controlled at any one time, BLDC is only any two are powered at any one time.
Max.

tlfamm
01-29-2017, 03:43 PM
in these Chinese split-phase motor's are the caps, if it fails, replace with a N.A. made motor run cap.
These caps, in my recent experience, will still be made in China. Specifically,a Kemet motor start cap. (Faston lug fell off the start cap on my old compressor: have too replace.)

Cheers
Roger

The cap I bought from these folks last year was US made, subject to the whim of the next MBA wizard who might select an offshore supplier for the company:

https://www.temcoindustrial.com/sc0005-motor-start-capacitor-108-130uf-110-125-volt.html

Temco caps can be purchased through Amazon.

MaxHeadRoom
01-29-2017, 03:47 PM
The cap I bought from these folks last year was US made, subject to the whim of the next MBA wizard who might select an offshore supplier for the company:



That particular one specifies Motor Start, these are usually short term rated, as opposed to motor run rated.;)
And generally lower value mfd.
Max.

tlfamm
01-29-2017, 04:20 PM
That particular one specifies Motor Start, these are usually short term rated, as opposed to motor run rated.;)
And generally lower value mfd.
Max.

Indeed - I offered it only as an example of a US made cap. Temco sells run caps as well:

https://www.temcoindustrial.com/shop/capacitors/run-capacitors.html

PStechPaul
01-29-2017, 05:34 PM
AFAIK motor start capacitors are generally higher capacitance value, and may be bipolar electrolytic with relatively high internal impedance, which limits their use to short term due to heating. Motor run capacitors are lower value and are usually polypropylene or oil-filled, designed for low impedance and continuous use.

A BLDC motor is very similar to an induction motor as far as the stator is concerned, but the rotor has permanent magnets. So it does not use induction and instead is a synchronous motor. It can be controlled by a VFD with PWM sine wave voltage, but square wave (or trapezoidal wave) controllers are simpler and cheaper. The VFD I made used rectangular waves (called modified sine waves), similar to the cheaper automotive DC-AC inverters, and they will power AC induction motors, although not as efficiently.

Some of the R/C motors are rated up to 1 or 2 HP, but that is at rather high RPM, and they are not built for long term continuous use. Also, in R/C planes the air speed and prop wash provide good cooling, but if you used it for a machine tool you would need to provide a high CFM fan or blower, and you would need additional step-down belts and pulleys to get a more useful speed.

wierdscience
01-29-2017, 05:44 PM
Where did you source that one Wierd, and do you have any experience/opinion regarding reliability?

There have been occasions where I could have put a water pump to use, and if they are worth a damn, $35 makes it cheap enough to have on hand.
I found a similar unit on amazon for $36, but it appears from the reviews that half of them only lasted a very short time.
https://www.amazon.com/Tooluxe-50635-Surface-Agriculture-Nozzle/dp/B00VQF6T6C/ref=sr_1_4?ie=UTF8&qid=1485666524&sr=8-4&keywords=1+2+hp+water+pump

(https://www.amazon.com/Tooluxe-50635-Surface-Agriculture-Nozzle/dp/B00VQF6T6C/ref=sr_1_4?ie=UTF8&qid=1485666524&sr=8-4&keywords=1+2+hp+water+pump)

I got mine here,but have used them from other vendors before with equal success-

http://www.ebay.com/itm/370558591841?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Like RC says in the post following your's,the caps are the weak points.Some will have actual electrolytic run caps,some will have nylon caps and still others will have tiny little PCB caps.

As far as using them for pumps,that all depends on what you intend to use them for-vs-the design of the pump,which is pretty crude.I know lots of people here where I live that use them for pond aeration or pumping water around a greenhouse.Like a lot of stuff from China it's a crap shoot,but considering the closest thing that is US made will be $200 + it may be a chance worth taking.

MaxHeadRoom
01-29-2017, 11:44 PM
A BLDC motor is so named because it represents a DC brushed motor turned inside out, only two winding's energized at any one time, the motor is practically identical to the AC synchronous except all three winding's are sine wave fed.
I have attempted to run a BLDC motor on a VFD with very poor results, Hitachi claim theirs can, but when I contacted them they said the drive will have to be factory set for a particular motor.
Max.

Joel
01-30-2017, 12:09 AM
I got mine here

Thank you sir.