# Best Dc Motor Controller



## rwm (Nov 26, 2016)

Does any one out there use a DC motor controller you are happy with? If so what is the make and model?
I am asking because I am not entirely happy with the KB controller I used for my South Bend lathe project. 

http://www.hobby-machinist.com/threads/the-new-south-bend-10k.30542/

It would need it to be reversible and be rated up to 1 HP. I have not seen much discussion on controllers so I think it would be helpful.
Robert


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## TOOLMASTER (Nov 26, 2016)

love daytons....


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## Ulma Doctor (Nov 27, 2016)

good old MC60 controllers are good OEM controllers, i believe they supply DC motors- somewhere around 2hp@95vdc


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## mikey (Nov 27, 2016)

I like Dayton controllers, too. I have two of them that were bought with ratings to match the motors they serve, off of ebay. They are both reversible, have a speed pot and have been flawless in performance. Sorry, don't have the model numbers.


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## rwm (Nov 27, 2016)

Those Dayton controllers sure are pricey. Do you know if they reverse the direction through the controller or just use a DPDT switch to switch the leads?
Robert


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## Ulma Doctor (Nov 27, 2016)

rwm said:


> Those Dayton controllers sure are pricey. Do you know if they reverse the direction through the controller or just use a DPDT switch to switch the leads?
> Robert


there is a reversing switch on the dayton controller


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## calstar (Nov 27, 2016)

I converted my lathe to DC( $200 for the motor, $100 for the controller, best money I've spent on lathe tooling!), using a* Minarik* controller, they have some good utube vid tutorials on set up

https://www.youtube.com/channel/UCdlNZXEzy_UlBPHI8AIStNg

I bought my MM22300C from *Galco*,  their customer service is excellent. They also have really good tutorials, especially for guys like me who didn't have a clue as to the what/how for the conversion.

Brian


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## calstar (Nov 27, 2016)

oops, double post.


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## TOOLMASTER (Nov 27, 2016)

minarik burn up easy.. not very forgiving


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## rwm (Nov 27, 2016)

Brian-That is super helpful. After looking at that site, it sounds like a PWM contoller would be quieter and smoother than my SCR controller. They make a 4 quadrant regenerative drive that would work well.
Here's a dumb question. What if I scrapped this idea and went with a servo drive system? I don't know much about them.
R


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## rwm (Nov 27, 2016)

OK. Here is what I have concluded from my research so far. Please correct me if I am wrong:

The main cause of noise/vibration I am experiencing is my selection of a SCR controller which is sending large amplitude pulses at 60Hz.
A PWC controller operating at 16KHz (stndard) would be much quieter .
A servo drive would work, but would require a more complex control system. This requires further research. It may be the ultimate solution.
I need a 4 quadrant controller to get the functionality I need.

I do not see that Dayton makes a controller that has 4 quadrant regen braking. Minarik makes one but it requires a large external resistor for brake energy dumping (not a deal breaker.) Also it is larger than my box (again not a deal breaker.) KB does not make one!? That chick in the Minarik video is kind of cute (except the voice.)

http://www.ebay.com/itm/MINARIK-NRG...869987?hash=item5d57cad863:g:EJkAAOSwNSxVMoWT

Robert


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## 4GSR (Nov 27, 2016)

Why do you need such a fancy controller?  The Dayton one I use for my SBL does fine, speeding up or even slowing down.  It handles dynamic braking ok.  No instant stops, but quickly stops when you need it to do so.  It has a forward reverse switch, but I use the old drum switch for reversing when needed.  Ken


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## rwm (Nov 27, 2016)

Ken- Please elaborate. What model controller are you using or at least what are it properties? PWC or SCR? Does it use a braking resistor? I admit reversing would be uncommon on my machine so perhaps I could just add a manual switch. I am concerned that all of the SCR controllers will be just as loud.

R


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## rwm (Nov 28, 2016)

TOOLMASTER said:


> minarik burn up easy.. not very forgiving


Really?! I thought the newer models were better. Have you had a recent one fail?
R


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## markba633csi (Nov 28, 2016)

I like the KB units.  I found a new old stock KBIC-125 on Ebay for around 15 bucks, blew the dust out of it,  wound up a .035 ohm "horsepower" resistor for it and it works fine.  DPDT switch motor leads for reverse (with power off) Yes they do make the motor hum a bit, but I think they are more reliable than the mosfet "treadmill" types.  Certainly easier to troubleshoot and repair- simple op-amp feedback, no digital jazz, tried and true.  Daytons are similar. 
My 2 cents.
Mark S.


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## TOOLMASTER (Nov 29, 2016)

rwm said:


> Really?! I thought the newer models were better. Have you had a recent one fail?
> R



Haven't bought any for a while...I just buy daytons now


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## rwm (Nov 29, 2016)

Thanks for the replies. Mark- just so I am clear on the function. Does your KBIC brake the motor or does it just coast to a stop? If you reverse it with the motor running will it blow the controller?

Also- I just got this very informative email and I thought I would share it:

Hello Robert,

In regards to SCR 4Q drives, they are definitely audibly noisier than PWM drives. SCR drives switch voltage to the motor at 120Hz, so they produce a hum at lower speeds. PWM drives switch at over 16kHz and send filtered voltage to a motor. This makes the motor run very quiet.

SCR 4Q drive can provide braking without a DB resistor because the motor energy is fed back to the AC line. On PWM drives, the excess energy is fed back into the drives BUS capacitor. If the BUS capacitor becomes over charged, that’s when the DB circuit activates and bleeds off the excess voltage on the BUS cap.

I hope this helps.
Richard Lopez
Applications Engineer

Robert


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## markba633csi (Nov 29, 2016)

Hi Robert- No braking on my setup, and I don't reverse it under power- I probably should have a latching switch for the reversing function but I'm just careful, and the circuits are fuse-protected.  I believe the controller has a "free-wheeling" diode which gives some braking after power down,  I'll have to double check that. 
Mark S.


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## rwm (Nov 29, 2016)

I don't know about y'all but I am tired of trying to use a caliper while the chuck is still spinning! Stupid, yes but I know my limitations (patience). The dynamic brake is a real safety and convenience factor for me. Also, with the 8" 4 jaw the lathe takes about 30 minutes to coast to a stop.
R


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## markba633csi (Nov 29, 2016)

I hear that. I think some KB units have braking. 
MS


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## rwm (Dec 1, 2016)

If you notice my South Bend lathe thread I just installed a KB SCR drive with braking and reverse. I was using the lathe last night and it works very well. It is only noisy when changing speed. I think this could be a problem on long facing cuts when I might change speed to maintain SFPM. I plan on keeping this controller for now and see how it goes. In the mean time I will look out for a deal on a PWM controller. I will certainly update this thread if I make any changes. I wonder if there would be interest in someone writing a tutorial on DC conversion in general as a reference?

The servo concept still intrugues me. Check this out!




Robert


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## GLCarlson (Dec 1, 2016)

markba633csi said:


> I like the KB units.  I found a new old stock KBIC-125 on Ebay for around 15 bucks, blew the dust out of it,  wound up a .035 ohm "horsepower" resistor for it and it works fine.  DPDT switch motor leads for reverse (with power off) Yes they do make the motor hum a bit, but I think they are more reliable than the mosfet "treadmill" types.  Certainly easier to troubleshoot and repair- simple op-amp feedback, no digital jazz, tried and true.  Daytons are similar.
> My 2 cents.
> Mark S.



Yep. Older KBs on fleabay, cheap, bulletproof, good up to a horse or two. I have several.


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## rwm (Dec 3, 2016)

I am still contemplating various designs. One thing I don't really have a handle on is rotary switches. Can someone help me understand them better? Take a standard 3 pole rotary with 3 positions. I get that each pole has a common terminal that can be connected to terminals on each side by moving the switch. But why are there two terminal connections on the common? i.e typically 2 and 4, 6 and 8, 10 and 12 are really the same terminal? Or do they disconnect when you turn the switch either way? In short, why does a 3 pole double throw center off switch end up with 12 terminals instead of 9? Anyone familiar?
Robert


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## markba633csi (Dec 3, 2016)

It varies depending on the brand and model.  You're right, normally you expect 9 contacts but not always.  It may be that each pole is actually 2 separate poles inside and they are tied together for extra current handling or reliability.
BTW I don't think you need (or want) to switch the neutral, I would just tie them all together. Just switch the hots. You don't want to compromise the neutral connection if the switch were to fail somehow.
Mark S.


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## rwm (Dec 3, 2016)

A lot of systems seem to switch the neutral also since it may not be at ground potential. There is no neutral in my 240v system anyway. I was just showing a common switch. I am trying to avoid separate switches for run/brake and forward/reverse with a braking resistor. I really need the resistor connected when the switch is in the center off position.
Robert

Edit: I guess I could do this with a 4 position 2 pole switch. Pos 0=off, Pos 1=forward, Pos 2=brake, Pos 3=reverse. 
I would still like to know if 2,4 6,8 10,12 are always connected on the 3 pos switch.


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## markba633csi (Dec 3, 2016)

Only way to be sure is to ohm them out with a continuity tester or meter.
MS


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## rbertalotto (Dec 6, 2016)

Somewhere on my web page are two articles on converting a lathe and a bandsaw to DC drive. In both cases I used the extremely inexpensive DC control board from Surplus Center $85)

http://www.surpluscenter.com/Electr...rs/90-180-VDC-SPEED-CONTROL-W-POT-11-2269.axd

These have been in operation in my shop for years with zero issues. I know of dozens in the field with no reported issues.

my web page www.rvbprecision.com


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