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DC motor controllers

DPittman

DPittman

Ultra Member
I need some basic guidance regarding motor controllers for dc motors. I'm browsing through Aliexpress and the lack of my knowledge combined with the poor product descriptions makes it a gong show.

I've salvaged a small 90v DC brushed motor from a treadmill. On the motor it also says 450 watt, 5.5 amp and 3700 rpm. I don't know how accurate these rating are but from what I gather it would be considered an extremely underpowered motor for a treadmill.

I'm considering a project for this motor and realize that the end use of the motor would likely determine the type of controller I would need, however I think the two distinction would be foot control vs panel control.
Tool post grinder, seeing machine or a bead roller are a few of the possibilities that I might try to make use of this motor in. The tool post grinder scenario I think is the most likely one.

I don't see any controllers on Aliexpress that list 110 volt, they all appear to be 220 volt? Can those be used with 110 volt?

It also appears that some controllers have to already have dc voltage supply? I need to go from 110v ac to the dc voltage.

My 90 volt specifications on the motor seems a bit unusual. Can I use a controller with higher dc output without immediately frying the motor?
 
450 watt is about 3/4 hp, ignoring motor efficiency. More than enough for the uses you list.

Most of the higher wattage dc controllers seem to want dc input, this one is a bit low on wattage but would likely work, just sketchy at full power


My mill uses a KBIC125 for a 3/4 hp 90v dc motor. A bit pricy but bulletproof as long as you don’t apply power with the motor disconnected. This I know.

KB Electronics KBIC-120 DC Motor Speed Control w/9884 Terminal Board : Amazon.ca: Industrial & Scientific

KB Electronics KBIC-120 DC Motor Speed Control w/9884 Terminal Board : Amazon.ca: Industrial & Scientific
www.amazon.ca

The kbic has a pile of interesting features - remote shutdown, hold, 0-7v control signal input, adjustable ramp, adjustable output, etc. Mine is getting tweaked for an Arduino-controlled RPM/SFM/Cutter Type/Material automatic system for RPM
 
whydontu said:
450 watt is about 3/4 hp, ignoring motor efficiency. More than enough for the uses you list.

Most of the higher wattage dc controllers seem to want dc input, this one is a bit low on wattage but would likely work, just sketchy at full power


My mill uses a KBIC125 for a 3/4 hp 90v dc motor. A bit pricy but bulletproof as long as you don’t apply power with the motor disconnected. This I know.

KB Electronics KBIC-120 DC Motor Speed Control w/9884 Terminal Board : Amazon.ca: Industrial & Scientific

KB Electronics KBIC-120 DC Motor Speed Control w/9884 Terminal Board : Amazon.ca: Industrial & Scientific
www.amazon.ca

The kbic has a pile of interesting features - remote shutdown, hold, 0-7v control signal input, adjustable ramp, adjustable output, etc. Mine is getting tweaked for an Arduino-controlled RPM/SFM/Cutter Type/Material automatic system for RPM
Click to expand...
Thanks for that info. Yes I just ran across that first Amazon link you sent me.
What are the main differences between that one you linked to and this one here
RioRand PWM DC Motor Speed Controller Switch Control 7-70V 30A Fuse(Black) https://www.amazon.ca/dp/B071NQ5G71/ref=cm_sw_r_apan_glt_i_CNEE9X3T7BB8448CTJ71?_encoding=UTF8&psc=1

I know the voltage output is lower but if I find one at 90 volts will it accomplish the same as your linked one?

Your second linked product is out of my price range right now. But I don't doubt that it is probably the best one to go with:confused:
 
DPittman said:
Thanks for that info. Yes I just ran across that first Amazon link you sent me.
What are the main differences between that one you linked to and this one here
RioRand PWM DC Motor Speed Controller Switch Control 7-70V 30A Fuse(Black) https://www.amazon.ca/dp/B071NQ5G71/ref=cm_sw_r_apan_glt_i_CNEE9X3T7BB8448CTJ71?_encoding=UTF8&psc=1

I know the voltage output is lower but if I find one at 90 volts will it accomplish the same as your linked one?

Your second linked product is out of my price range right now. But I don't doubt that it is probably the best one to go with:confused:
Click to expand...
The 7-70V 30A controller referenced needs a 70 volt DC supply.

You can run your motor on 70 volt, it just won’t reach the same maximum RPM.

Big snag is it needs a separate 70 volt DC power supply, and that costs $$$.

The first one I selected accepts regular 110VAC wall outlet power.

Here‘s a knock-off of the KBIC controller

www.aliexpress.com

61.51C$ |110v 220v Ac Input 90v 180v Dc Motor Speed Controller 10a - Motor Controller - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com

I‘ll spend a few minutes seeing if I can find one with free shipping
 
I guess it would depend on the application but is it conceivable to use the controller from the treadmill, change the switches to something smaller you have speed control and on off even a funky deadman switch?
 
combustable herbage said:
I guess it would depend on the application but is it conceivable to use the controller from the treadmill, change the switches to something smaller you have speed control and on off even a funky deadman switch?
Click to expand...
And you can get a display that shows how many calories you would have burned if you went jogging instead of standing next to the lathe
 
whydontu said:
The 7-70V 30A controller referenced needs a 70 volt DC supply.

You can run your motor on 70 volt, it just won’t reach the same maximum RPM.

Big snag is it needs a separate 70 volt DC power supply, and that costs $$$.

The first one I selected accepts regular 110VAC wall outlet power.

Here‘s a knock-off of the KBIC controller

www.aliexpress.com

61.51C$ |110v 220v Ac Input 90v 180v Dc Motor Speed Controller 10a - Motor Controller - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com

I‘ll spend a few minutes seeing if I can find one with free shipping
Click to expand...
Hmmn thanks for the work and info. That kbc knock off is still really expensive. I'm guessing it must be way better than the other options? It looks very similar to the board in my DC variable speed lathe.
I think I'll give one of the other ones you listed under $40 a whirl maybe.
 
So I got a dc motor controller from Amazon

DC Motor Speed Controller, 24V-90V Adjustable Single Phase Motor Speed Controller for 24V, 36V, 90V DC Motors https://www.amazon.ca/dp/B07FZ38M54/ref=cm_sw_r_apan_glt_i_PTWNW5D4HPB0XYE3G0G2?_encoding=UTF8&psc=1

And just trying it out on the motor now. I've only been able to try the motor on 12 volt and 20 volt batteries and it seems to run ok on those. The brushes look a bit rough but I think ok.
1647456588845570224257449051641.jpg

The dc controller seems to make the motor really hum loud and it will only run at a low speed and rather roughly. The rheostat dial seems to make it run worse by no faster as I crank it up. Definitely something not right there.
I'm wondering about testing the output dc voltage with a multimeter but
@whydontu
suggested above that it was not good to run his KBIC controller with the motor not connected. Is that ok with my cheap controller? Any suggestions?
 
As long as there is a motor connected, you can read the motor voltage with a multimeter by reading across the + / - connections. How much current does the motor pull at 20 VDC?
 
I think I'm going to jump ship before I fry something. There's alot a brush sparking and noise when running the motor with that thing. When I run the motor with a 20 volt dc drill battery the motor seems to run smooth with good torque (but of course not real fast) . This is probably why people pay much more for the controllers like you have. :confused:
 
How much does the controller weigh? I'd be happy to test it in my shop, I have quite a bit of accurate test gear and could run diagnostics. My guess is the motor current is too high at low RPM and the controller is struggling. Could vent be a simple as needing a capacitor across the motor DC supply to smooth out PWM noise.
 
whydontu said:
How much does the controller weigh? I'd be happy to test it in my shop, I have quite a bit of accurate test gear and could run diagnostics. My guess is the motor current is too high at low RPM and the controller is struggling. Could vent be a simple as needing a capacitor across the motor DC supply to smooth out PWM noise.
Click to expand...
Thanks for the offer. The thing weighs about 3/4 of a pound (.33kg).

I think I will see if I can return it. I guess I will have to be on the lookout for wrecked treadmills in hopes of finding a useable controller. I don't think I can spend the money a good KBIC controller would cost. I'm just playing.
 
I just remembered... I bought a motor speed control for my lathe a few years ago thinking it might be the problem, as it turns out it wasn't but I kept the controller anyhow just in case someday it fried. Low and behold it is a KB electronics Inc controller!

I think I want to keep it for my lathe for the just in case someday scenario but I'd also like to use it to try out my motor more fully. HOWEVER I can't risk frying it because my lack of electronic knowledge. Would you
@whydontu
be willing to help/guide me to wiring it correctly?
16474623142905615530738079102259.jpg
16474623436063784211470519943055.jpg
 
I grabbed a couple of free treadmills recently to get the motors for possible use as:
a)upgrade for my 7x14 lathe
and/or
b)variable speed motor for my drill press.
I watched a lot of YT videos and read a bunch of online info.
I liked the approach from 'The Aussie Shed' guy: cheap AC controller feeding a bridge rectifier then DC to the motor.

I bought this controller (same item is cheaper at AliExpress if you can wait)
https://www.amazon.ca/gp/product/B082ML24LH/

Bridge rectifiers are cheap and common; I had a few on hand.
Something like this bolts to an empty spot onthe heat sink:
https://www.amazon.ca/Twidec-Housing-Electronic-Rectifier-KBPC-5010/dp/B07PJ6168B/

I had the components but didn't get around to assembling anything until I blew (easily) the controller on the mini-lathe and sent that off to Peter Brush (olduhfguy) for repairs. It worked OK on the treadmill motor (a '2 HP' 90 volt), better after I swapped the pot in the controller for a lower value one. I put everything into a good (grounded) metal box with a fuse, switches (ON/OFF, FWD/REV) and hooked it up to the minilathe motor and it works fine. The speed knob needs to be advanced from about 7 o'clock to 11 before it starts up, and I haven't measured the RPM but I was more concerned with decent low RPM performance and it does that OK. I've done a few little projects and made a few mistakes since, and it's still doing fine. I have the repaired controller back from Pete Brush but haven't bothered to re-install it.
 
DPittman said:
I just remembered... I bought a motor speed control for my lathe a few years ago thinking it might be the problem, as it turns out it wasn't but I kept the controller anyhow just in case someday it fried. Low and behold it is a KB electronics Inc controller!

I think I want to keep it for my lathe for the just in case someday scenario but I'd also like to use it to try out my motor more fully. HOWEVER I can't risk frying it because my lack of electronic knowledge. Would you
@whydontu
be willing to help/guide me to wiring it correctly?
View attachment 22043View attachment 22044
Click to expand...
That’s a good board, easy to wire.

L1 goes to 120 volt AC neutral
L2 goes to 129 volt AC hot

A+ goes to motor positive
A- goes to motor negative

You need a 5K to 10K pot to adjust speed. Connects to P1 P2 and P3.

This one is easy to wire but a bit pricey:


This one is decent quality but needs to have the wires soldered on:


manual:

 
whydontu said:
That’s a good board, easy to wire.

L1 goes to 120 volt AC neutral
L2 goes to 129 volt AC hot

A+ goes to motor positive
A- goes to motor negative

You need a 5K to 10K pot to adjust speed. Connects to P1 P2 and P3.

This one is easy to wire but a bit pricey:


This one is decent quality but needs to have the wires soldered on:


manual:

Click to expand...
Awesome thank you for all the help.
 
whydontu said:
That’s a good board, easy to wire.

L1 goes to 120 volt AC neutral
L2 goes to 129 volt AC hot

A+ goes to motor positive
A- goes to motor negative

You need a 5K to 10K pot to adjust speed. Connects to P1 P2 and P3.

This one is easy to wire but a bit pricey:


This one is decent quality but needs to have the wires soldered on:


manual:

Click to expand...
Oh boy that didn't go so well I'm afraid. I got a potentiometer like the first one linked to (but a 10k) and hooked up the board as suggested. Motor started up and it was very sparky on the brush end. I quickly unplugged and tried once more and nothing not even a hum. Tried the motor again just on a 12 volt battery and it seemed okay. Man I hope I didn't fry this board. How would I test it?
 
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