'funny' you should ask...as I'm going to 'acquire' a few for projects..

#1 wood lathe

#2 thickness sander

The concept is easy, just bodge the motor onto 'device', mount the 'control' box, plug in and go.

My understanding is they are probably 3 phase,2HP 90Volt DC motors, so super smooth.

Odds are the shaft is 'Metric 5/8 or 3/4.'

 I've got over 100 live edge 16" wide, 1" thk serving trays to  deal with and there is NO way I'm running a sander over each one for an hour ! so I'll fab up the sander station. Going to use the 'treadmill' as the infeed-outfeed tables with adjustable speed. The actual sanding drum will be a separate motor.

Guy next door has a wood lathe with 8' bed neding a motor/speed controller. The 3 phase unit that was on it did work on single phase but, well, needed to be 'borrowed' for another task...

Nice thing about the treadmills is the 'screen' to display a 'speed'. Once you've calibrated it a handy chart pasted next to it makes life easy.

Dusty

The treadmill motor's control system is built-for-purpose for the treadmill, typically the control circuitry has safeties and stuff, and it ramps up and down slow, and despite their ratings... they generally don't pull a heavy load for much. 

Best way to run them, is to use a controller like the Minarik MC-1.

https://www.minarikdrives.com/dc-drives-and-motor-controls" rel="nofollow - https://www.minarikdrives.com/dc-drives-and-motor-controls

i did... and it worked... but the downside, is that they're not particularly stable when drilling... they will bog a fair amount.

What I did, was fitted a 3-phase motor and a Variable Frequency Drive to it.  I used a unit that someone pulled off an industrial machine, and I found a pallet of used Allen Bradley 1305 240v 1.5hp drives for cheap ($25 each), fed 'em single-phase.  Most of my machine tools are running 3phase motors on VFDs fed with single phase, and they're all plenty strong.

gee Dave, you sound like my friend ! He 'acquired' a skid of stuff...used a 3phase controller on his single phase motor for his milling machine. sure is smooth. Did a similar setup for a wood lathe that spins 8' long columns.

I tore  a 20 year old treadmill apart and it has a Leeson 1.5HP, 90 volt DC motor. Used an A-B 1365 controller and well it spins ! ,though some tweaking is required.

be nice to score some 'economical' controllers though..I just 'found' TWO 1hp DC motors with 40:1 gearboxes on them. course it'd help if I had a use for them but yeesh BRAND NEW, tossed out... they HAD to come home....

Jay

steve(ill) wrote: You should mention that not just any 3 phase motor and VFD will work... You only have 240 v single phase at most supplies... The motor has to be a 208-240 V and not a 480 v unit I believe......... then the VFD is also a phase converter as it is taking single phase and converting to 3 phase power... Some just vary the FREQUENCY ... maybe some also convert the 240v input to 480v output, but that would be a " special VFD" also.

No, Steve...  there's some things to look out for, but it's not that restrictive... one simply needs to apply practical concepts.

Let's say you have a 5hp 380v spindle motor in a Maho MH600E CNC milling machine... and a 240v single-phase panel.  The solution, is to feed the 240v single-phase into a 7kva dry transformer (salvage yard, $20) from the SECONDARY side.  Connect the transformer's PRIMARY side for 480v, and connect the two phase leads to A and C of an Allen-Bradley 1336S 10hp 480v VFD (Ebay $60) and program the VFD's MOTOR parameters for 400v or so.  In my case, I set the MH600 for 120HZ as highest frequency and left it at that... because the MH600E has a hydraulically-shifted gearbox integrated into the CNC controls.

On my Monarch 10EE lathe, I removed the Reliance Ward-Leonard MG drive, and replaced it with same arrangement, with a 10KVA transformer feeding a first-gen Allen-Bradley 1336F (brand new in box, but 30 years old... $43 from an industrial surplus place in Uclid, Ohio) driving an 1800rpm Allis-Chalmers 7hp 3-phase motor wired for 480.  I fitted the spindle and motor shaft with a Gates Polychain toothed-belt drive, and programmed the VFD for 0 to 210hz or so...  oh, and I yanked the motor's cooling fan, chopped the stub off the shaft and mounted a 6" 240v cooling fan under it's shroud powered direct from the mains contactor, so it's always got steady cooling flow regardless of shaft speed.  The motor spins at 1800/60*210=6300rpm, into that 3:1 belt drive, for 2100rpm at the spindle, and it's BEASTLY strong.

My Johannsen radial drill is fitted with a Bridgeport 2J head that's driven by a 3hp 240v 3ph motor sourced from a junkyard that I USED to be able to trade steel scrap drops pound-for-pound for motors, gearboxes, and such... (they're gone now... snif)...  It uses the AB1305  AA12A drive, direct fed 240 single phase in.  My Bridgeport mill uses same setup, but I just took the standard Bridgeport pancake motor's leads from the switch, and connected them to the VFD, added a braking resistor, and called it good.  I leave the head in the middle belt position for most milling.  Every SO often I'll need to shift it into backgear, but most of the time, I just use the VFD knob.  The pancake motor still runs it's factory cooling fan.  When I wrap up the speed (IIRC limited around 130hz) it howls pretty good, but I've never had overheat-at-low-speed problems.

The 1308 series is actually factory identified as being useable on single phase input, and derating is noted where necessary.  The 1336 series has a DC bus input, so if a person WANTS to run single-phase, just use a single-phase rectifier bridge off the 240v mains to feed the VFD, and it's fine.  I don't... since I'm cheap, I just buy 'em surplus, and buy 'em about 30% larger, and that solves it.

There are SOME drives (particularly those built after around 1995 or so) that have Phase Loss Detection.  IIRC Yaskawa, Mitsubishi, and Siemens had that feature... and MOST of the time, one could disable it in software.  SOME would automatically de-rate themselves when in disabled mode.  There's a few that simply WON'T tolerate phase loss faults... when that happens, put about a 2uF capacitor and a 1.5k resistor in series between either leg and the 'missing' phase, and it'll usually shut up and play nice.

That's a great score, Jay... are they 90v motors, or lower?  If you really, really, really needed to... you could make a self-propelled electric shop-lift... one motor on each side, with full differential steering... a short boom with hook for lifting and toting engines, transmissions, stuff like that... with a trio of truck batteries on a platform 'tween your feet, handlebars in front'a ya, two space-saver spares as your main drives, and two ZTR casters in the back...

 Boy,,I'll tell you,,I ENVY the heck out of you guys that know your way around juicetricity,,,especially that Dave Kamp,,,, I'm amazed at all them 10 dollar words you guys throw around,,,and,,,you do know what you talkin bout,,,,

 

Im thinking my OLD VFD were just frequency drives... and your talking an INVERTER/ frequency drive. 

Hi Steve!

Variable Frequency Drives do what they do... by converting AC line current to DC, which is fed into three inverter bridges controlled by a microprocessor that synthesizes AC... at 120 degree intervals... for three phase.  They're great gadgets in many ways, and that's one of 'em.

Yeah, if you have industrial machine tools that need some sort of three phase to operate, a second-hand VFD will do the task.  They're designed to be connected directly to a motor, and to set them up, you program them with THAT motor's voltage, frequency, and ampere ratings, and it will regulate it's output so as to not fry the motor.

Since they're rectifying the incoming AC power into DC, it doesn't really matter HOW it gets it's incoming power... the only gotcha, is that if you try to feed a 5hp motor with a 5hp VFD, but you're only feeding two of the three legs, the diodes in that rectifier bridge are loaded a bit hard on account that one of the legs is not carrying load- it's all on the other two.  The most common solution for this, is to oversize the VFD by 30% or so.

The other problem guys run into, is that they want to drive a 1hp or 2hp 3-phase motor, but when they go searching, they look for units in that size range that are rated for single-phase input, and the marketing types at big companies KNOW this, so they advertise units for single-phase in, and put a HIGH price tag on them.  Skip that!!!

If you have a surplus machine tool, the motor will USUALLY have choice of low (208-230) or high (430-480) voltage operation.  Likewise, you'll see that a used 480v VFD is substantially cheaper than a 230v unit... and you'll also see that a 5hp, 7hp, or 10hp VFD is much cheaper than a 1hp to 4hp unit...  and that's because of two factors-  first, people want the low voltage, 2hp unit, and second, industry tends to use many more 5-10hp 480v units.

Find surplus single-phase dry transformers... if it can be wired for 480 in, and 240 out, and carries anywhere from 1.5kva up to 10kva, snag it.  Wire them for 240 on the secondary, and 480v on the primary.  Hook the secondary to your line supply, and you'll have 480v single-phase on the secondary.  From there, you can feed the VFD... and the big advantage is, that since you're at 480, the motor current will be HALF what it'd be at 240... that input bridge (running only two legs) will be seeing substantially lower current.

Works great!

...and...

more guys got 230 than 480 in their workshops !!

my 'life' would be simpler with 3phase here but $$$ to bring into building!

Jay

 

 ----------------------

SO if you put 3  phase 480 v into the  VFD, you get 3 phase out and have "speed control box".......... and if you put single phase 480 volts into the VFD , it "simulates" a 3 phase output for the  motor ?

 

I took a 208 V 3 phase motor  ( about 20 years ago) and ran 240v single phase into it, with a series of START capacitors and a series of RUN capacitors and a manual button I hold in for 2 seconds on the START circuit..... it " simulates" 3 phase output determined by the capacitors I used ........ and like you said, I get 2 HP out of a 3 HP motor... the VFD sounds like a newer version and programmable !!

lou and steve's way is called 'phase convertor'. it generates the 3rd phase allowing you to run 3 phase motor on house 240 AC ( which is 2 phase ). Both are 'lossy' systems whereas VFD units are highly efficent.

wide's Ardunio approach can work and easy to control low voltage motors. Some easy, off-the-shelf ways are 'E-scooter/ E-bike' electronics and 'Drone ESC' units. E-bikes can have 72 volt battery power and they run 3 phase motors. Drones Electronic Speed Controls(ESC) are all 3 phase units as well. The problem is the design/build of the power supplies(PSU) and the less than 240V rated controllers. While the PSU design is fairly easy, you'll blowup the ESC if you attach it to over the 72 volts it's designed for.

There's a few utubes of guys using Delco alternators as motors using  ESC units. Very simple and safe, using 12 or 24 volts.ESC is a $20 item, PSU maybe $30 .

For 'normal' folk, I'd suggest a proper VFD. A LOT safer, works out of the box !

course now that I've typed all this I'm thinking I should grab an old alternator and see how many HP I can get out of it !

Jay

TramwayGuy wrote: The reason a 230v VFD is more expensive than a 460v VFD (same HP rating) is because it is handling twice the current.

More a circumstance of supply and demand...  480v units are more common in industrial environments, and 230v units are in much,  much higher demand by guys who need to run industrial tools in a home garage.

Essentially, yes.  It's a 3-phase inverter bridge made up of thyristors... solid state switches... and they're being pulsed on and off, in 1-2-3 sequence. by the microprocessor.

The microprocessor can run that inverter bridge at any frequency.  It can modulate the 'on' time, to increase voltage and current through the motor windings.  It can measure the voltage and current, and LIMIT either or both, according to the motor's capabilities.  It can change the speed at a controlled rate, to accellerate smoothly.... and it can switch the thyristors in a reversing pattern to rapidly slow the motor, and change direction... and a variety of other groovie things... all programming.

steve(ill) wrote: I took a 208 V 3 phase motor  ( about 20 years ago) and ran 240v single phase into it, with a series of START capacitors and a series of RUN capacitors and a manual button I hold in for 2 seconds on the START circuit..... it " simulates" 3 phase output determined by the capacitors I used ........ and like you said, I get 2 HP out of a 3 HP motor... the VFD sounds like a newer version and programmable !!

That is called a Rotary Phase Converter, and it's the basis of a very popular design first published by Fitch Williams.  I've built several... I recently traded my latest all-automatic unit for an engine...    Here's my post from Smokstak back in 2014:

-------------------

Fitch Williams is the properly-attributed publisher... his rotary converter white paper explained it all several decades ago.

One can make a rotary converter out of a knife switch, a three-phase motor, and a piece of rope (wrap and pull, throw switch). Anything beyond that, is strictly luxury.

I built my self-starting converter using Fitch's white paper as guidance for run and start-cap values, then I added protection breaker, input, start cap, and output control contactors, detection of generated leg output voltage a timer circuit (to detect overrun of the start cap control), and finally, a 'fault-out' loop that would stop the converter, and not allow it to automatically restart, if there was some failure condition.

The basic system, however, is Fitch Williams.

Here's the 'republished' and simplified description from 1998:
http://www.practicalmachinist.com/vb/transformers-phase-converters-vfd/fitch-williams-converter-design-balancing-instructions-101882/" rel="nofollow - http://www.practicalmachinist.com/vb...ctions-101882/

I believe Fitch passed away about three years ago... a really great guy.

----------------------------------

 I always enjoy the heck out of reading Dave Kamp's articles on all things technical,,!!  This guy knows his way around all thet stuff, but best of all can explain things so dummies like me can understand some of it. I really enjoyed visiting with him for a couple of hours, a few years back. Altho,,,,he was prolly bored to smithers listening to this old country guy,,,,,,,,but,,,,but,,,I DO know something bout D14 engines,,,,, ( I know he was facinated with eating breakfast  at same place GWB did),,,,

 Come back and see us sometime, Dave,,Ya hear,,??

I'll do that, Joe.  Dunno when I'll get dispatched that way, but I won't sneak through without givin' ya fair warning.

The little VFDs I use to run my lathes, mills, and grinders... they're the baby brothers of the 3-phase traction inverters that propelled the trains I used to teach classes on.

Those trains were anywhere from 650v up to 25,000v... 250hp to 800hp motors... and of  course, the trains had 'auxiliary inverters'... they ran constant 60hz, and generated 480v 3ph, 230v 3ph, and 120v, as well as 72v battery-charging...

 Ten Four,,Dave,,,,I'm gonna keep you in mind for some assistance on something I'm wanting to do on my Air Compressor driver. It currently has a Leland-Farady 3HP 1740 driving the AO Smith V4 single stage and does good most of the time, altho I have been noticing that sometimes the motor lugs down quite a bit and that ain't doing the motor any good. But then the next 100 restarts, it just runs smooth,,prolly just old windings,,,??? I bought a 7.5 HP 3 phase 1750 that I plan to some day get a phase convertor to use it on the compressor,,but they keep telling me they want real dollars,,,,,,

Good thing about the PE is they have an internal braking resistor up to 5 hp (480 volt rated drives), whereas Magnatek drives all require external braking resistors. Lot of inertial load for travel and hoisting motions on cranes, plus short decal times are desired for safety purposes. A lot of hoists now use a closed loop vector drive with encoder feedback instead of open loop systems with a mechanical load brake. Closed loop system does well with keeping load overspeed under control.

Just think, not long ago we were cursing Reliance DC drives and replacing a lot of power cubes and field contactors to keep them going, not to mention changing brushes and cleaning commutators.