# Can I Use a Router Speed Control on this Moter (Please see photos)?



## I Gotta Tell Ya (Sep 25, 2019)

Yikes, sorry these photos are so monstrous. This is AFTER I resized them.

Anyway, below is an inexpensive "Router Speed Control" unit sold by Harbor Freight. It says it will work on "any universal AC/DC brush type motor, 15 amps and under." I'm an idiot when it comes to electronics.





Below are some photos of a little project I am working on for my shop, re-purposing a kitchen juicer to run a buffing wheel. The motor runs at about 8000, which will likely be too fast for my application. Again, excuse my ignorance, but will a speed control unit like that pictured above work on the motor below? Is the motor pictured below a "universal AC/DC brush type motor?" Thanks so much for your help. Appreciate it.


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## catsparadise (Sep 25, 2019)

That looks like it's a universal motor. A universal motor is just a DC motor with the stator and rotor connected in series, that way, whichever way the voltage is applied the magnetic fields conspire to push it round in the same direction. I can see what looks like brush housings on the PCB material at the fan end.

I imagine that the speed controller will either control the duty cycle of the AC supplied to the motor or will rectify it and use some sort of pulse width modulation to generate a variable average DC level to control the speed. So the short answer to your question, in my opinion, is yes, it will work. I could be wrong, but the controllers aren't that expensive (found an identical one on ebay, finest chinesium, for sub $20).

Rob


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## Bi11Hudson (Sep 25, 2019)

I am apparently going blind in my old age. I also see the brush looking plastic on the fan end. However, the brush rigging doesn't look like it's on opposing sides. The stator windings look more like a shaded pole motor, and/but there is also a capacitor in there. 

In any case, I personally would recommend *against* using a light dimmer /router speed control. A "router" speed control is basically a light dimmer with beefier components. The final output is not a true "sine" wave and will cause severe heating on an induction motor. The extent of heating will vary depending on how much speed reduction is used, how far below base speed it is run. i.e the slower it runs, the hotter it gets and the less power it has. If it's important, change the motor, using a drill or the like.

The only "safe" motor will have brushes 180 degrees apart, such as a hand drill, router, or sewing machine motor. As stated, a "series universal" motor... An AC/DC motor. The full answer requires a working knowledge of electricity, not electronics. There is a vast difference and I find myself trying to answer properly without going into an electrical education. 

Bottom line, if the motor doesn't have brushes, don't use a speed controller or lamp dimmer. Period!

Bill Hudson​


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## RobertB (Sep 25, 2019)

Better pics of the brush end would help, where you could see both brushes and the commutator at the same time, but it appears brushes 180 degrees apart to me. I also do not see a capacitor, only other thing I see looks like a thermal protector zip tied to the windings.


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## Flyinfool (Sep 25, 2019)

An induction motor that is running on 60Hz power has a max speed of 3600 rpm. That means that if this one is running at 8,000 RPM it is not an induction motor. Odds are it is an AC/DC motor and will be fine with the Router controller. BUT pay attention to heat, that motor looks very small to be running a buffing wheel, as you slow the motor down the fan is also slowing down and giving less cooling air, you have also removed all of the ducting that kept the cooling air close to the motor. Watch out for the magic blue smoke. all electronics run on magic blue smoke. If you let it out it will stop working.

The way the router controller works is that it chops off the AC waveform from the zero crossing first and move that cutoff point wider toward the peaks. this means that the motor is still getting the full peak voltage. Simply reducing the voltage will cause motor heating, by modifying the wave form there is less power available but it is still at the correct voltage.


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## markba633csi (Sep 25, 2019)

Light dimmers work in a similar way, they are called "phase-fired ac controllers"


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## I Gotta Tell Ya (Sep 25, 2019)

Thanks, everyone. I really appreciate your time and expertise. If necessary, I can take some more photos.

One main question I have at the moment. If I plug in this motor to the speed control unit and it is not the right motor, will it burn out the motor or in any way damage it? Also, assuming this works, is it realistic to assume I might be able to back off the motor to the RPM ranges of, say, 1000-3000?

Thanks again, and will check back in a bit.

Thanks!


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## RobertB (Sep 25, 2019)

Flyinfool said:


> that motor looks very small to be running a buffing wheel,



That is an important point. That motor is only 140 watts, so you are in the range of a dremel tool power. You are not going to be able to drive a very big buffing wheel. 1" to 1.5" maybe. At that diameter to get the SF/M needed for buffing you will need the full motor rpm.


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## vtcnc (Sep 25, 2019)

RobertB said:


> That is an important point. That motor is only 140 watts, so you are in the range of a dremel tool power. You are not going to be able to drive a very big buffing wheel. 1" to 1.5" maybe. At that diameter to get the SF/M needed for buffing you will need the full motor rpm.


^This reply should be considered first before you dive into the electrical part of the project.^ The size of the motor, rpm needed, etc. is highly dependent on the application. What exactly are you trying to achieve here? There are small buffing wheels and big buffing wheels, the extreme ends of the buffing wheel size spectrum shouldn't even be on the same tool let alone the same motor. 

With that said, you have received some sound advice on the electrical side. If you are considering a purchase of a router speed control, why not purchase a cheap tool to run the appropriate size buffing wheel for your application? Harbor Freight may be your best friend in this case.


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## I Gotta Tell Ya (Sep 25, 2019)

RobertB said:


> That is an important point. That motor is only 140 watts, so you are in the range of a dremel tool power. You are not going to be able to drive a very big buffing wheel. 1" to 1.5" maybe. At that diameter to get the SF/M needed for buffing you will need the full motor rpm.



Thanks for your advice on that. 

Actually, to clarify, this motor is from a home juicer -- a Juiceman -- and has pretty good torque. What I'm actually using it for is buffing and polishing and lapping the guitar picks I make, which are all made of plastic, so my main hope is to run this with very fine grit ratings of 8000-12,000, with very little resistance. I'm not grinding or sanding stone or metal. It should work fine for my purposes, but will know more once I try it. 

Does this make more sense?

Sorry if I created any confusion.

best, 
IGTY


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## I Gotta Tell Ya (Sep 25, 2019)

vtcnc said:


> ^This reply should be considered first before you dive into the electrical part of the project.^ The size of the motor, rpm needed, etc. is highly dependent on the application. What exactly are you trying to achieve here? There are small buffing wheels and big buffing wheels, the extreme ends of the buffing wheel size spectrum shouldn't even be on the same tool let alone the same motor.
> 
> With that said, you have received some sound advice on the electrical side. If you are considering a purchase of a router speed control, why not purchase a cheap tool to run the appropriate size buffing wheel for your application? Harbor Freight may be your best friend in this case.



VT, this first one is an experiment. I got this juicer for $10.00 at a garage sale. If this works, I will then probably make a heavier duty unit -- for heavier sanding and lapping -- with a router as the motor. My materials need to generally be run with water, for cooling, as one of my plastics will warp with too much heat.

Below is a photo of a benchtop wet lapping machine that I'm trying to replicate or approximate. These are used a lot in the jewelry and rock industry. That sucker costs $550.00. Heck, I can make one for less than $100. I'm really having a lot of fun experimenting and also saving beaucoup bucks.


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## silence dogood (Sep 25, 2019)

Good news the motor has brushes. Did the unit that the motor come out of have push buttons to control the speed? That's another clue that it is a universal motor.   The bad news is 150 watts.  That translates to about 1/5 hp (750 hp is about 1 hp).  That's pretty wimpy.  Also, the motor has a fan. which means that it has to run at a certain minimum speed or it will get mighty warm.


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## I Gotta Tell Ya (Sep 25, 2019)

Do Good, yes, it has a two-speed switch, high and low. We'll see how it works. If not enough torque, I'll explore the router option itself, which would have much higher torque and hp.

Thanks! I'll pick up one of those speed controller things today and see if it works. 

Take Care.


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## I Gotta Tell Ya (Sep 25, 2019)

Update. Bummer. I plug it in and the speed controller had no affect on the speed. On the FULL setting, the motor turns at the regular speed. On the Variable setting, the motor doesn't turn at all, even turned to high. Any thoughts? Any other inexpensive way to slow down a motor like this, if this won't work. 

Thanks Again,

IGTY


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## RobertB (Sep 25, 2019)

I Gotta Tell Ya said:


> Any thoughts? Any other inexpensive way to slow down a motor like this, if this won't work.



2 pulleys and a belt.

As for the speed control, Harbor Freight has a very high D.O.A rate on electronics (just look at the reviews on this item) so I would test it. See if it has output on the variable setting. If no voltmeter available, plug a lamp (incandescent) into it.


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## brino (Sep 25, 2019)

I Gotta Tell Ya said:


> Any thoughts?



Yep. Test that new speed control on a known good electric drill or router!
-brino


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## silence dogood (Sep 25, 2019)

Hmm.  Are there coils in the rotor( the part that turns) ?  If there is, it should be a an universal( why it does not work, I can't you an answer right now). If it doesn't, then it most likely a shade pole. To get the two speed, there are two coils. There should be a third wire (excluding green that is connected to the frame which is ground). A single coil gives it a slow speed ( on some fans the other coil has more turns so it gives you a med speed), both together give you fast speed.  One problem with shaded pole motors they have a low start up torque which fine for fans.  Universal motors have a high start torque which is good for drills.  Other than that either there something wrong with this motor or I'm missing something.  Sorry about you buying the speed control, but you will still be able to use it for something.  Sorry about being long winded, but I'm trying to keep the explanation as clear a possible.


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## I Gotta Tell Ya (Sep 25, 2019)

Update #2:

Okay, here's what I found. The company that makes the juicer from which the motor comes is called Juiceman. They make two similar models called The Juiceman and The Juiceman Jr. The more expensive models has two speeds, the Jr. model only single speed. It does not appear that the speed control will work on the two-speed model, but it worked just fine on the single-speed unit. I also tested the unit on a incandescent lamp and it did fade the bulb. 

Okay, fine and good. But still some issues.

1) Even turned all the way down on the speed control unit, the motor still turns too fast. It sounds like it's in the 4000-5000 range. I need it much, much slowly, ideally down as low at 1000 rpm. A couple questions: A) Could you run two of these speed control units in series, thereby lowering the rpm even more? 2) Is it possible a higher-quality speed control from a reputable maker would lower rpms more? A router usually runs over 10,000 rpm, doesn't it? How much would a good speed control lower that speed?

2) RPM: Is there an easy, inexpensive way for me to get a reading on how low the rpm is going on this unit? Excuse my ignorance.

3) Below is the specs for the motor used in various models on the market. Should this motor be relatively easy to find online?
*Motor specifications*

Motor type: Permanent magnet DC, rectified for AC use
Voltage: 115V (US plug)
Maximum rpm: 2,800
Minimum rpm:  800
Motor torque: 48 oz-in (0.339 N-m)
Watts in: 245
Watts out: 154
Running current: <1A
Motor shaft outer diameter: 0.312″ (5/16″) stainless steel
Thank You!
Scott


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## ericc (Sep 25, 2019)

If you are using a permanent magnet dc motor, a good way to lower the speed is with a step down transformer.  This has the advantage of maintaining current, and therefore torque.  Be careful not to demag the motor field with too much current.


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## RobertB (Sep 25, 2019)

Yard sale, pick up a $5 corded variable speed drill


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## I Gotta Tell Ya (Sep 25, 2019)

ericc said:


> If you are using a permanent magnet dc motor, a good way to lower the speed is with a step down transformer.  This has the advantage of maintaining current, and therefore torque.  Be careful not to demag the motor field with too much current.


Eric, thanks. On (I think) PM several months back they had suggested a used treadmill motor, which looks like a good way to go. 

So that would be called a "DC step-down transformer," or something like that?

Thanks very much, Eric.

IGTY


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## brino (Sep 25, 2019)

I Gotta Tell Ya said:


> A couple questions: A) Could you run two of these speed control units in series, thereby lowering the rpm even more?


Nope, sorry.



I Gotta Tell Ya said:


> 2) RPM: Is there an easy, inexpensive way for me to get a reading on how low the rpm is going on this unit? Excuse my ignorance.



Yep, many options:
https://www.harborfreight.com/digital-photo-sensor-tachometer-66632.html
https://www.ebay.com/itm/Laser-Phot...250915?hash=item5d8f3012a3:g:T18AAOSwx0hdLh-X
https://www.ebay.com/itm/Non-Contac...709995?hash=item1f00efed2b:g:13oAAOSwWy1dcIc~
...and you'll likely find a lot of use for it.



I Gotta Tell Ya said:


> On (I think) PM several months back they had suggested a used treadmill motor, which looks like a good way to go.


A tread mill motor is a great option for wide speed control range.
However, it is likely much more bulky.

I have picked up several treadmills for free (well.. for hauling them out of basements.... but I typically take them apart to make it easy).
But, you may need to do some work to replace the big push-button treadmill interface with a simple switch and potentiometer.

-brino


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## I Gotta Tell Ya (Sep 25, 2019)

brino said:


> Nope, sorry.
> 
> 
> 
> ...


Brino, thanks very much for all the info. 

I'm in Los Angeles, probably the treadmill capital of the world, so I'll work on hunting down a treadmill repair shop.

One other thing I was wondering, though. Harbor Freight makes some pretty cheap stuff. Is it possible a higher-quality router speed controller would bring down that RPM more? It looks like a pretty simple device.

Thanks So Much.


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## Bob Korves (Sep 25, 2019)

Here is an easy to use and inexpensive non contact digital tachometer.  Less than $10 including shipping, your choice of vendors.  They work quite well.  I am really happy with mine.  The link should post "least expensive, including freight, first."








						digital non contact tachometer | eBay
					

Buy and sell electronics, cars, fashion apparel, collectibles, sporting goods, digital cameras, baby items, coupons, and everything else on eBay, the world's online marketplace



					www.ebay.com


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## silence dogood (Sep 25, 2019)

LOL, a permanent magnet motor.  Okay, instead of slowing the motor down, how about using pulleys or gears? Not only would your output be slower but you'd have more torque.  Just a thought.


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## I Gotta Tell Ya (Sep 25, 2019)

Bob Korves said:


> Here is an easy to use and inexpensive non contact digital tachometer.  Less than $10 including shipping, your choice of vendors.  They work quite well.  I am really happy with mine.  The link should post "least expensive, including freight, first."
> 
> 
> 
> ...


Bob, thanks. Looks like a winner.


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## I Gotta Tell Ya (Sep 25, 2019)

silence dogood said:


> LOL, a permanent magnet motor.  Okay, instead of slowing the motor down, how about using pulleys or gears? Not only would your output be slower but you'd have more torque.  Just a thought.


Silence, might be a possibility down the road. I'm a quick learner, but I don't know the pulley thing, so it would require a lot of experimentation. What I like about this potential juicer solution is that the whole unit is encased in the original juicer body, waterproofed, and perfectly set up for what I need to do. But 8000 rpm would cut it. 

thanks,
igty


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## bill70j (Sep 26, 2019)

RobertB said:


> 2 pulleys and a belt.



FWIW, I have a DIY tool post grinder that I run with an HFT Router motor in combination with their Router Speed Controller.  The controller will take the motor from 22,500 RPM to a minimum of 8,000 RPM at the lowest controller setting.  That works fine for internal grinding using mounted points and small wheels.

But in order to get the RPM down for external grinding, I made a couple of pulley combinations to get the RPM to the 2,000 to 4,000 range.  RPM is directly proportional the pulley circumference, and therefore to pulley diameter.


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## RobertB (Sep 26, 2019)

No offense, but I really think you should reassess the viability of this project. Given the parameters, especially of wanting to use the existing juicer housing, really limits your options for speed control to electronic means only. 

As others have pointed pointed out, reducing the speed of this motor will also greatly reduce the torque and make the motor run hotter. The fan also running slower will exacerbate this. Even routers reduced to 6000 rpm run much hotter than they do at full rpm. Read the instructions for most variable speed drills and they tell you if running at reduced rpm's for extended periods to periodically run the drill unloaded at full speed to let the fan cool it down.

 The juicer was also designed for very intermittent duty, like 30 seconds per day. If I understand your intended use, it is for a production application where it will be running more than that 30 seconds per day. I understand and greatly subscribe to the d.i.y. aspect of projects, but unless you are using components suitable for your application it will be a frustrating endeavor.


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## I Gotta Tell Ya (Sep 26, 2019)

RobertB said:


> No offense, but I really think you should reassess the viability of this project. Given the parameters, especially of wanting to use the existing juicer housing, really limits your options for speed control to electronic means only.
> 
> As others have pointed pointed out, reducing the speed of this motor will also greatly reduce the torque and make the motor run hotter. The fan also running slower will exacerbate this. Even routers reduced to 6000 rpm run much hotter than they do at full rpm. Read the instructions for most variable speed drills and they tell you if running at reduced rpm's for extended periods to periodically run the drill unloaded at full speed to let the fan cool it down.
> 
> The juicer was also designed for very intermittent duty, like 30 seconds per day. If I understand your intended use, it is for a production application where it will be running more than that 30 seconds per day. I understand and greatly subscribe to the d.i.y. aspect of projects, but unless you are using components suitable for your application it will be a frustrating endeavor.


Good point. I'm not opposed to abandoning this.

Question: Is it conceivable to run a standard electric router? And if so, is there an easy way to rig the pulley system to achieve the desired range of RPM from about 1000-3000? If so, is it best to run it with the unit to also lower the RPM, or return the thing to HF and go with the straight router and pulleys.

I assume, like a bicycle, I'll want to run at least two pulleys. I can talk about size later, but where's a good place to buy the pulleys?

Thanks for your advice.

Appreciate any further insights. 

best, 
IGTY


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## RobertB (Sep 26, 2019)

The best bet is to find a motor closer to the RPM you want. All motors run much more efficiently at their designed RPM, plus the screaming of a high reving universal motor gets old pretty quick.


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## matthewsx (Sep 26, 2019)

You might consider using a small stepper motor with a driver and PWM controller. You woprovide uld have to figure out the waterproofing but they are cheap and will provide very granular speed control.

One other thought is if you need a waterproof package you might pick up a blender with variable speed already built it. Can probably be had for just a few bucks at goodwill.

Cheers,

John


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## francist (Sep 26, 2019)

This might be a little out in left field, but instead of a system of pullies what about a friction drive using a regular fractional horsepower motor? 

I’m looking at the desired product — horizontally mounted lapping disc, basically — and it reminds me of an electric potters wheel. Very smooth and variable speed control for those is obtained by setting a motor with a driving wheel 90 degrees to the driven wheel, much like a set of bevel gears. By moving the friction wheel further from or closer to center it provides a faster or slower rate of rotation. Think “surface feet per minute” here, same theory. The nice thing about the fractional horsepower motor is it would provide lots of jam but very little noise, and pretty easy to come by. And, if you wanted to wet sand, very easy to shroud the motor component. Here’s a crude sketch if it helps.




-frank


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## I Gotta Tell Ya (Sep 26, 2019)

Thanks, Gents, will respond more later. Can't thank you enough. Believe it or not, I'm a full-time English prof and I gotta go teach a class.

Back at ya in a bit.

Thank You!


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## Flyinfool (Sep 26, 2019)

Your best bet may be to go with an induction motor. They can be had with native shaft speeds of 1140-1710-3420 RPM. they are quiet, may not have great starting torque but you don't need that either.
Maybe the motor from an old box fan would be close to perfect I am guessing that HI speed is around 1,000 rpm. you just need to make a mounting and figure a way to keep the water out of the motor. Most box fans already have 3 speeds to play with.

Another option is to find something with a gear motor that already runs at near your desired RPM.


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