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Doc Nickel
11-12-2007, 10:25 PM
Just pulled apart yet another old treadmill, this time with a very nice Baldor 90VDC continuous-duty frame-56 motor.

The problem is, the speed controller says 90VDC at 5 amp, or 10 amp with the heat sink (which it has.) The motor, however, says 90VDC at 14.6 amp (to produce 1.5HP at 4800 RPM.)

I'm presuming that this controller would only give me roughly 2/3rds the speed and 2/3rds the HP, right? Making it something like a 1HP, 3200 rpm motor?

So to get full power out of this badboy, I need a speed controller that can give me 90VDC at 15 amp. I gave eBay a cursory check, and found one 120V (10 amp) and several 12/24V (at various amperages.) A similarly cursory check of Am.Sci&Surp didn't show any speed controllers at all- which probably means I'm looking in the wrong spot.

Any suggestions for good vendors or suppliers?

Doc.

sidegrinder
11-12-2007, 11:09 PM
Surpluscenter dot com always has some, but a quick check didn't reveal anything with the snort you're looking for. It looks like to get over the 1hp hump they'd need 180 volts.

http://www.surpluscenter.com/item.asp?UID=2007111220575197&item=11-2102&catname=electric

Keep lookin'...

rkepler
11-12-2007, 11:37 PM
KB has some drives that would do it, and you can often find them on eBay. Here's the data sheet for one: http://www.kbelectronics.com/data_sheets/kbcc.pdf I could be more specific, but don't know what other requirements you have (reversing, regulation, etc.) If you do look at one of the KB drives let me know - I think I have a friend with one spare, might go cheaper than eBay.

lazlo
11-12-2007, 11:47 PM
Doc, 90VDC @ 15A: you're talking about a 1500 Watt controller -- that's a big controller, with a big heatsink

Like Russ says, Minarik and KB make controllers up to 16A, but they're several hundred dollars. You might get lucky on Ebay...

J Tiers
11-12-2007, 11:49 PM
Just pulled apart yet another old treadmill, this time with a very nice Baldor 90VDC continuous-duty frame-56 motor.

The problem is, the speed controller says 90VDC at 5 amp, or 10 amp with the heat sink (which it has.) The motor, however, says 90VDC at 14.6 amp (to produce 1.5HP at 4800 RPM.)

I'm presuming that this controller would only give me roughly 2/3rds the speed and 2/3rds the HP, right? Making it something like a 1HP, 3200 rpm motor?

So to get full power out of this badboy, I need a speed controller that can give me 90VDC at 15 amp. I gave eBay a cursory check, and found one 120V (10 amp) and several 12/24V (at various amperages.) A similarly cursory check of Am.Sci&Surp didn't show any speed controllers at all- which probably means I'm looking in the wrong spot.
Doc.

Not necessarily true.

The motor will draw whatever it needs to run with the given load. If the load is not as much it will draw less.

So you should be able to get full speed, which merely depends on the voltage. You HAVE the voltage available, and the motor won't draw the full amperage unless under full load.

The ultimate power may be less than the motor maximum, if you are limited to 10 vs 15 amps by the controller.

However, the controller, if it is the typical rectifier and triac type controller*, can have the triac replaced with a slightly higher rated one, which may gain the full capability that the motor allows.

Many of those controllers also have feedback of motor speed, which sets the speed fairly "solidly". That can make the ultimate current limit a bit more important.

It may also have an actual current limiting circuit, which presumably is set for the devices used. That may need adjustment if you are using a larger triac.

* the most common ones I have seen use a particular TDA controller chip, one that was developed for use in washing machines. Those versions are made with a triac as the controlling device,and have a bridge rectifier to obtain the DC for the motor.

There are a number of websites with information on defeating undesirable features (like soft-start), and also on "hot-rodding" the units for higher power.

lazlo
11-13-2007, 12:19 AM
Here's an auction with the Minarik 90VDC, 15A controller, apparently with the same motor you have Doc :)

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280171561021

Here's a fancy Minarik 21A PWM controller:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200171073039

sch
11-13-2007, 12:40 AM
I fiddled with a Minarik controller from Surplus Center, IIRC #23111
Anyway, it was rated 5A, or 10A with heat sink. Driving a PM
treadmill motor with nameplate of 2.5hp (!?!) presumably at the
rated 7100rpm and 18A as listed current, the Minarik bogged down
once the motor speed got up to 1000-1500 range, IOW well below
max power and began to cut out for a few seconds, then longer
before finally shutting down for a time. Suspect over current limiting
was doing its job.
It had a pronounced cogging at low speeds also, as would be expected
with an SCR drive.

Doc Nickel
11-13-2007, 12:56 AM
Lazlo- Not the same motor (mine's a Baldor, but the layout with the fan and flywheel are almost identical) but that's exactly the same speed controller I have. The tag on the side- which you can barely read in that pic- says 5A, or 10A with the heat sink (which is the aluminum frame it's on.)

But that's precisely the same controller, down to the tags and labels.

JTiers- What I'd like to do with this motor is install it in my old JET mill-drill, in place of the 1-1/2 HP 230VAC motor and worn-out vari-drive (that had seven belts and five bearings between the motor and spindle.)

It's an R8 machine, and I'd like the HP to be able to turn 1" endmills (through aluminum anyway) without risking blowing something up.

On that note, I'm also looking for a speed controller that'll give me as much torque as possible even at lower speeds. I plan on having a two or even three-step pulley system so I have a range of speeds, but I still might want to run the motor down to 500rpm, and still have the oomph to push a fair drill bit through steel if need be.

Doc.

J Tiers
11-13-2007, 01:04 AM
Lazlo but I still might want to run the motor down to 500rpm, and still have the oomph to push a fair drill bit through steel if need be.

Doc.

Not gonna happen.........

The torque is fairly limited for that motor, since it produces its power at a pretty high rpm. You seem to want to go to 10 percent of RPM, and still produce the same or similar power. Not realistic.

The power is related to the RPM and the torque. if the RPM goes down, the torque has to go UP for the same power (force x distance).

The torque is proportional to the input current, which has a limit. Above that you saturate the iron, or overheat the motor.

You MAY get acceptable performance over a 5 to 1 range of speed (and power). But for drilling steel you want to keep power same at a lower speed, which can only be done with a torque multiplier, namely belts or gears.

Doc Nickel
11-13-2007, 01:15 AM
The torque is fairly limited for that motor, since it produces its power at a pretty high rpm. You seem to want to go to 10 percent of RPM, and still produce the same or similar power. Not realistic.

-Oh, okay. I wasn't sure, and I'm no electrician, but I thought I recalled that there was a way to keep max torque yet still drop the speed through something like pulse width modulation... but I suppose I'm not going to find a controller that can do that on eBay for $20, right? :D

So in other words I'm going to need to keep the speed up at probably the top third, and regulate the gross spindle speeds through belting, right?

Which makes me wonder about those so-called 115V/3phase motors out of the other treadmills I got earlier in the summer. They came out of some heavy-duty gym-quality treadmills, and the speed controllers/power supplies are huge and complex things. I wonder how well they'd hold up the torque at low speeds...

Doc.

J Tiers
11-13-2007, 01:46 AM
-Oh, okay. I wasn't sure, and I'm no electrician, but I thought I recalled that there was a way to keep max torque yet still drop the speed through something like pulse width modulation... but I suppose I'm not going to find a controller that can do that on eBay for $20, right? :D

So in other words I'm going to need to keep the speed up at probably the top third, and regulate the gross spindle speeds through belting, right?

Doc.

You CAN "hold torque", but you can't "hold power", by slowing. And the torque ain't that high due to the high speed.

So you'd be drilling slower with motor slowed than if you used belts etc.

wirewrkr
11-13-2007, 10:23 AM
Try www.youngssurplus.com
good people, always an interesting collection of stuff.
Robert

Bill Pace
11-13-2007, 10:45 AM
Doc, I scrounged up the almost identical set-up you got there (the controller is the same) and hung it on a mill-drill and was tickled pink with it, so much so, that when I replaced the M-D with a 6x26 mill I moved it over to it and again really liked it.

I dont think it'll quite do what youre describing but I think you'll be surprised at what it WILL do --- and to gain variable speed is enough to make me overlook a lot --- I would usually alternate between 2 pulley settings ... a low and a medium speed (90-95% of the time on medium) and when on the lower setting it was quite potent.

That controller certainly isnt one of the better ones, -- use it and keep an eye on ebay till a better one comes along. I did, and while I didnt notice any appreciable difference in 'power' the ability to not have to turn the potentiometer back to zero to restart was a definite plus.

Dont know how your set-up is, but on the M-D and 6x26, it was too easy a change-over to the DC set-up to NOT do it and see what would happen --- was a 'bolt-up' except for making a bushing to adapt the mills pully to the DC motors shaft.

I have since moved on to a Bridgeport clone with 3ph and a VFD----now THATS a sweet set-up!:)

Doc Nickel
11-13-2007, 08:03 PM
So with the controller I have, it'll probably be roughly a 1HP motor, right?

So what happens if I put a heavier load on it? Say a drill binds, bearing siezes, I climb mill too fast, etc. In other words a stall or near-stall condition.

Will I blow out the controller? Assume it's a momentary thing, not that I leave it bound up and struggling for more than a second or two. I know something'll overheat if left that way for an extended period, I guess I'm asking if the first indication of a stall or overload will be the speed controller exploding or something.

Doc.

Too_Many_Tools
11-16-2007, 01:23 PM
There are a number of websites with information on defeating undesirable features (like soft-start), and also on "hot-rodding" the units for higher power.

Do you have links to these websites?

This would be a good discussion thread to supply this information for reference.

TMT

cebump
11-16-2007, 02:44 PM
Doc

I have a southbend 9 and a home built bowl lathe running treamill motors using controllers from these guys. http://www.beel.ca/ I am in the treadmill business and have tried a ton of different motor/controler combinations with a wide range of succes. This set up has been the best so far especially on my bowl lathe. I start with wood blanks in the range of 24" that weigh a ton and this has been the only drive that does not puke either from lack of tourqe or over heating at the slow speed i start off with. I have a 3hp pacific scientific motor on it for now. If I recall the drive boards were less than 75 per unit. If you have any questions let me know.
Brian

Doc Nickel
11-17-2007, 07:42 AM
Thanks cebump. Good source.

Okay, next question: This is the speed controller for the big 220VDC 4HP monster out of a huge commercial treadmill. Here's the overall layout:

http://www.docsmachine.com/machineshop/TMA-1.jpg

And here's a closeup of the speed controller itself:

http://www.docsmachine.com/machineshop/TMA-2.jpg

"Precor" is the brand of treadmill. The shiny plate it's bolted to is the backside of a large finned extruded aluminum heat sink. The black things are large capacitors about 2" long. The motor actually plugs into the red/black terminal just to the right of the caps. I don't know what the square object in the lower left is- it's not a switch or anything (as in there's no rocker or lever on the other side) but presumably there's a reason it's bolted to the heat sink.

Wires from the SC to the motor are surprisingly small- maybe 10 gauge? Thick, but not what I guess I'd expect for something feeding over 200 volts to a four horsepower motor.

I suspect that this is much like the Baldor drive- significantly underrated for the motor, probably providing half or less of the nameplate power. Googling the PCA and PCB numbers on the right yeilded zero results. Precor's page has no technical data whatsoever, apart from owners' manuals in PDF format.

So- can any of you fellows tell me what this controller is rated for, and better yet, how I can use it? (IE, get rid of the "brain box" board and run this thing off a pot or other manual control.)

(Thanks- and just you wait 'til I start asking about those 115V 3-phase motors. :D )

Doc.

cebump
11-17-2007, 01:03 PM
Doc
the precor as well as most recent vintage commercial treadmills lower boards are so integrated with the other areas of the treadmill that I have never been able to seperate them for just a motor use. Someone who knows them better may be able to, but most have speed sensors, elevation power, onboard diagnostics and other stuff. I have stacks of the used boards that I cannot stand to toss, so if you find a way to do it please post it. The three phase ones you mentioned, I picked 2 of those up the otherday. The controls that came with mine may be able to be isolated and used as a speed control. If it works I will let you know.
Brian

Evan
11-17-2007, 01:27 PM
The square four terminal block is a full wave bridge rectifier. The capacitors filter the output of the bridge.

BTW, those capacitors were made in the 51st week of 1998. That type and vintage are known to fail early.

J Tiers
11-17-2007, 09:50 PM
That is a much newer type than the old triac and rectifier types.

It seems to run from DC, where the others processed AC and converted to DC just for the motor.

The large IXYS part in the middle (Q1) is probably a Mosfet or IGBT used for PWM motor control. While IXYS makes SCRs also, they wouldn't be used with DC supplies.

Doc Nickel
11-17-2007, 11:17 PM
So the lefthand board is probably both a DC power supply, as well as the 'brain box' that runs the show?

Meaning to use this speed controller I'd need to use both boards, and finagle controls through the dashboard port...

Sounds like it'd be easier (though hardly cheaper) to get a commercial speed control. On that point, this is a 220VDC motor- I assume I could run it off a far more common 180VDC power supply/controller, and it'd simply run that percentage slower in RPM?

Would HP/torque also be reduced by that percentage, or is that a function of the amperage? (And if this 18A motor got 180VDC at 18 amps, could supply close to or right at the rated 4HP, just at a slightly slower top RPM?)

Sorry for all the questions and multiple subjects, this is outside my range of expertise. :D

Doc.

CCWKen
11-18-2007, 12:22 AM
Looks like you need at least the two boards on the left. The center is the power supply and left is the motor drive. The far right box looks like a line filter. You might as well use the whole works.

Doc Nickel
11-18-2007, 01:00 AM
Cebump implied I'd have to do just that. I suppose it depends on what I use this particular motor for- I have plenty of uses for 1-2 hp motors, but 4hp is overkill for most of them, with the motor itself physically oversized for almost all of them.

That's why I'm so interested in that Baldor 90V that kicked off this thread- it's the perfect physical size and power for a couple of projects (bandsaw, homebrew belt-grinder I'd like to make, remotoring the lathe or the old mill-drill, etc.)

Naturally, I'd really like to be able to just find an inexpensive, off-the-shelf controller that'd feed these things and run 'em right, but it looks like that's kind of a pipe dream. :D Probably why so few tools have a variable DC motor- a single-phase AC and a couple of pulleys are way cheaper.

So at least for the moment, I can use the existing speed control/power supply with the Baldor, it'll just be current-limited to 1HP 'til I can get a different control. But it looks like this big can will need something large and semi-exotic and probably pretty expensive to run it....

Doc.

cebump
11-18-2007, 09:31 AM
Doc

My knowledge of elctronics is very limited to say the least, but I enjoyed playing with the spare parts I have had over the past 20 years. What it came down to me was the motors were useful that I scavenged but the electronics were not. The boards I posted a link to work as well as I can imagine on both lathes for very little money. I like many have been known to spend $1000.00 worth of my time to solve a $50 problem just for the fun of it. The board i have can be used for 110 or 220 btw. I do have a new one to play with though, an AC drive with a variable speed transmission. If you ever need info on the different commercial treadmills let me know as I have access to a lot of info. good luck

Kernbigo
11-20-2007, 12:41 PM
check out this one I'am using there control, Graham motors and controls
Kernbigo