New mill, to me that is!

[kvom]

That's a 3PH plug.  How is the spindle speed controlled, if at all?  Belts?

[steamer]

That's a 3PH plug.  How is the spindle speed controlled, if at all?  Belts?

Mechanical variable speed just like a Bridgeport.    knob is on the top right side of the head.

Uses the same "Salisbury Clutch" speed control typically found in ATV's and Ski-mobiles.  Plus hi and low range

Dave

[awake]

On the topic of 3-phase and single-phase on the same machine - FWIW, my BridgePort has an original BP powerfeed on it, likely installed from the factory ... and from the start requiring a separate 110v single-phase plug. No transformer on the machine.

Again, FWIW - which is probably not much!

[Hugh Currin]

This is reaching back into the dark recesses of my mind, and that from books and very little experience.

If I remember, there are two 3 phase connections, wye and delta. A wye config looks like a star with each motor coil (for example) connected to the other three on one end and to the juice on the other. A delta config looks like a triangle with each motor coil connecting between the lines of power. With delta there is no current carrying neutral line.

Most (is this true??) US small industries use a wye config. Here the line to neutral voltage is 120v. For this config the voltage between each power leg is 208v, line to line. It's not 240v (120+120) due to the difference is phase between each power line, they don't reach max at the same time.

I think three phase voltage is specified as line to line. i.e. A 240v three phase supply will have 240v between each incoming line. It would then have (240//sqrt(3)) 139v between each line and neutral. I just measured the output from my VFD with single phase input of 248v (124v to neutral). I measured output of 250v line to line and 160v line to neutral. So instead of 120v line to neutral you're getting 160v. Will this work instead of 120v for control circuits?? I now question these numbers. I believe the high frequency voltage chopping done by the VFD is messing with my readings.

Now I am concerned. My 3P lathe has some 120v control circuitry. It originally pulled 220v from the 3P input to a transformer to get 120v. When this transformer burned out I just put the control circuit between one line and ground. This worked fine for many years but with a really shaky rotary converter (just a 20HP motor connected 3P to machines with 1P 220v across one line to line. Spin it up and throw the switch. I will continue running and produce shaky 3P power.) But since, today, I'm rewiring for a new VFD I think I'll run a separate 120v line in.

Thanks. This thread may have saved me.

I agree, if you don't have 3P power then a VFD is about the easiest way to run 3P equipment. There are also static and rotary inverters, but VFDs allow variable speed. I just hope my motors hold up to the "not really sinusoidal" input power, the downside of VFDs.

Updated to correct errors. Corrections in italic

Any two of three leads of a 3P 220V will have 110V.  Unless the plug wires go directly to the motor housing, I'd suspect that the electronics power is accommodated already.  Should be obvious when you plug it in if the electronics are live.

No - any ONE of the phases will measure around 100V TO NEUTRAL. The 230V refers to the voltage from one phase to another. Certainly, that should become obvious when (if) you plug it in like that(!)

The simplest solution to running a VFD in a US house is to take the 110-0-110 feed from the breaker box and run the VFD between the 2 lives.

[Admiral_dk]

The formula is something like :

Voltage between two Phases / Tan(-120 degrees) = Voltage between Phase and Neutral.

Here in Europe that will be 400Vac. / 1.732 = 231Vac. (close enough to the 230Vac. we have here).

So in the if you have 220Vac. in the US, it will be 381Vac. between phases - but that is probably not how it works as the 220Vac. is two 110Vac. 180 degrees apart .... But then again - not much in the US makes much sense to me     

[Art K]

Kirk like Dave said! Motor is a single speed 1740 rpm. Spindle speed is changed by hand crank and a high low gear change.
Art

[steamer]

It seems pretty obvious from the second photo that it has mechanical Variable speed.    It wont move much if the spindle isn't turning   I believe there is even a note saying dont turn it if it's not running.

Dave


Here's a vid.      there is a speed indicating dial in the front and the hand crank is on the side.....

<a href="https://www.youtube.com/watch?v=Eb7G2LXa5f0" target="_blank">http://www.youtube.com/watch?v=Eb7G2LXa5f0</a>

[john mills]

The variable speed drive turning the handle while it is not running is just trying to clamp the belt between the two sides of the pulley the drive needs to be running so the belt can climb up the tapered sides of the pulleys .
same as if the load is blocked and it can not turn and you keep jogging trying to get it free the belt can be driven between the sides bending the levers or damaging parts which position the sides of the pulley.or can tear the belt.
Heavy intermittent loads can be hard on these drives .i have had to make parts and repair a few of this type of drives as the machines where i worked were driven by these styles of drive in a range of sizes .with jam-ups they could be destroyed with jog happy operators.
i also run a beaver cnc mill for a few years with hard work mostly machining tool steels it was quite rattly .after a
bit of this type of work.

   John

[Art K]

Dave,
That looks about right, although mine has an extra power on & off switch to the right of the spindle switch. Apparently OSHA mandated. I sent an email inquiry to Invertek and hopefully I will hear from them tomorrow after I get home from work and can get the ball rolling on powering up this beast. I took a tape measure to work yesterday to figure out how tall it is, 7 foot 2 inches. John thanks for the tip to be ware of intermittent cuts and jogging. The mill I use at work now has a 4 position pulley so that hasn't been a concern. Does anyone have any thoughts on a mill vise. I came across a Bridgeport 6" vise but it only opens to 5". One of the jobs I intend to use the mill for needs at least 5 7/8. A new Kurt will easily open that much but they are not cheap. Any alternatives or should I just bite the bullet?  The Kurt D60 vises I have seen on ebay have been more reasonable but seem to be in CA and are over $110 shipping, which defeats the the point of looking for a less expensive alternative.
Art

[kvom]

My feeling is:  I got a nice mill for scrap price, I can afford a good vise.

[john mills]

i always demand a good vice most good work depends on  precision and being able to hold well .
you should not have much trouble with the drive the work i did was with tough hot work tool steels and the jogging was with these types of drive on metal working machinery (bending and shearing) and jam ups were the machine comletly blocked not able to turn.

[Art K]

Kurt,
I have to admit that thought crossed my mind. Wife says this is an expensive hobby. I do realize that with my Tormach pcnc1100 I only have a 4inch vise and If I needed something bigger I could drag it home and slap it on the Tormach.
Art

[Hugh Currin]

You're right. Its tan(-120) or sqrt(3) (1.732). I found the 1.414 on a couple of websites but can't now find them again. As I said this is reaching way back into my faulty memory. Or, maybe I am loosing my mind. I corrected my post above. Thank you.

The formula is something like :

Voltage between two Phases / Tan(-120 degrees) = Voltage between Phase and Neutral.

As far as nothing in the US making sense, I live here and nothing makes sense to me either. Especially the last number of years.

.... But then again - not much in the US makes much sense to me     

Thanks again.

[BillTodd]

Nice mill. Looks to have a SWI Trak A.G.E 3 (or MX2) cnc  not just a DRO :-)

A very well featured and easy to use conversation cnc controller (I have the EDGE one with two axis control) .

Bill

[MJM460]

Hi Hugh, the 1.414 (or square root of 2) factor is the ratio between peak voltage and rms voltage.  Could possibly be the source of the confusion.

MJM460