Good DC motor and drive

[JRoque]

Hello,

Not sure if this belongs in this forum but here it goes:

I purchased this motor and drive from Surplus Center. The motor is $20 and the drive $40. My expectations were low when I saw the price but was I surprised. The motor is truly not the best quality I've seen but at that price it's way more than I expected. It's one of those "treadmill" motors.

The drive, on the other hand, is superb. It can output 130 VDC @ 10A to drive most DC brush type motors. It's loaded with great features but the best is the constant torque. I slowed the motor speed to what it seemed like 60 RPM and could not stop the motor shaft. The drive will increase the power to compensate for load and it does it better than anything I've seen. You can set upper and lower speed limits and control rotational speed by adding 10K potentiometer. If you want to get fancy, you can change the pot for an DAC and control the speed from your computer. It also has a dynamic brake that uses a resistor to electrically stop the motor; very useful as an emergency stop if a machine starts to eat your arm, etc.
Here's the drive's manual for your reference.

I'm waiting delivery of a new lathe I ordered. As soon as I figure out how to cut parts with it, I'll swap its motor/gears for this DC & drive combo. And the drill press better watch out cause I might swap it's motor too.

Later,
Julio

[JRoque]

I should mention the drive is an OEM version and not exactly as shown in the manual. FYI.

Julio

[Al_The_Man]

That looks like a pretty good deal, Minarik make a good product, at least it is a DC motor and control, the other treadmill motors that were being sold surplus were Universal DC/AC motors with a triac control. these are better and should make a half decent spindle control.
Al

[Moondog]

Originally Posted by JRoque Hello, Not sure if this belongs in this forum but here it goes: I purchased this motor and drive from Surplus Center. The motor is $20 and the drive $40. My expectations were low when I saw the price but was I surprised. The motor is truly not the best quality I've seen but at that price it's way more than I expected. It's one of those "treadmill" motors. The drive, on the other hand, is superb. It can output 130 VDC @ 10A to drive most DC brush type motors. It's loaded with great features but the best is the constant torque. I slowed the motor speed to what it seemed like 60 RPM and could not stop the motor shaft. The drive will increase the power to compensate for load and it does it better than anything I've seen. You can set upper and lower speed limits and control rotational speed by adding 10K potentiometer. If you want to get fancy, you can change the pot for an DAC and control the speed from your computer. It also has a dynamic brake that uses a resistor to electrically stop the motor; very useful as an emergency stop if a machine starts to eat your arm, etc. Here's the drive's manual for your reference. I'm waiting delivery of a new lathe I ordered. As soon as I figure out how to cut parts with it, I'll swap its motor/gears for this DC & drive combo. And the drill press better watch out cause I might swap it's motor too. Later, Julio

With this motor and controller am I right to assume that the only power supply you need is 110VAC to the controller?.. The controller then converts to the VDC as required by the motor?.... or do you need anything else?..

[JRoque]

Correct, I plugged it to the AC outlet on one end and to the motor to the other end of the drive. I also soldered a 10K pot to the board's speed control terminals. Nothing more is needed. I might add later a switch on the DC side to reverse the motor direction.

What's not clear to me is if the 3 terminal speed control (where the pot goes) is isolated or not. Most of the active components on the drive are on the bottom side of the PCB so I can't really tell. The manual, however, seems to indicate this terminal is isolated. Adding optical isolation should be easy though; there's even a 12VDC port right on board.

Julio

[windsor]

Hi I bought one of the minarik drives that you mentioned ( NRG10–115AC–2Q. )I've hooked it up to my 3 in 1 machine , and am quite happy with it . I've read the manual , and the board from surplus center is a bit different than the one in the manual . I'd like to hook up a dynamic braking resistor , I've tried one ( 20 ohms at 300 watts) , but it trips out the over voltage . I noticed that there are no jumper pins on the inhibit personality header as shown in the manual . ---do you happen to know if the jumper points are soldered together on the bottom of the board to (disable output ?) ---is it posible to solder two wires to the header on the top of the board with out dammaging something underneath ? Thanks Mike

[JRoque]

Hey Mike, happy new year.

I haven't had a chance to look underneath the board but I suspect it would be a matter of just soldering a pair of pins or wires directly. I'm thinking that these pins and the missing pots are either bypassed or set with a fixed resistor. I just ordered another motor and drive set so will be looking into mods shortly.

BTW, what motor did you use with your 3 in 1?

JR

[windsor]

Hi Julio
Thanks for the reply . I used the treadmill motor that you mentioned as well . At the moment I've just hooked up the motor to the lathe part of the machine . I had to make a shaft extender for the motor and a pulley . I monted the motor by drilling some holes in the face to use the 3 in 1's orriginal face mount configuration . Looking at the size of the treadmill motor I was a little reluctant at first , (it's about half the size of the 3/4 hp dc motor that came with the machine ) but it has lots of power ( possibly more than the ac motor ). I'm now thinking about changing the mill motor as well and possibly my drill press . I could use a dpdt switch to use the same controler with both motors .
I did find that when I switched the line voltage with the motor under power ( i.e. as an emergency stop )that it would also trip the over voltage LED , so I wired a switch between the middle of the speed pot and the low side of the pot for frequent motor stops and starts, while leaving the speed setting the same . If I can figure out how to get the braking to work I'd also like to use a micro switch as an automatic carriage stop for threading . The way the board is running now though there is a pretty long decel ramp setting , and I noticed that the adjustment pot for that ( as shown in the manual ) is not on the board . Mike

[BobLWeiss]

Are you using this for a spindle? If so how are you connecting your bits to the motor shaft? It looks like its threaded but I can't think of a way to connect a collet to it. Do you have pictures?

[windsor]

Hi Bob : I'm using the dc motor to replace the existing ac motor. It just drives the existing pulleys on the machine that drive the spindles . The shaft on the treadmill motor is 17mm , I bored out a short piece of 1 inch shaft and attatched it to the treadmill motor with grub screws .

[Al_The_Man]

Originally Posted by windsor : I bored out a short piece of 1 inch shaft and attatched it to the treadmill motor with grub screws .

Mike, You might need to include the translation this side of the pond for grub screws = set screws
Al

[JFettig]

I am currently using one of these motors and their 8amp controller on my mill, My motor came with a 2.5" double pully and I have a 2" on my spindle to put out around 8000rpm. It works quite nicely, cuts really fast. I believe my controller would have the constant torque because I can hear my motor bog down then speed up in the begining of the cut. It seems slightly delayed, probably because of the crazy speeds I am running it at.

Jon