Heavy 10 220vac 3ph

[Ironcross44]

Apologies if this has been discussed (new here)

I have a nice SB Heavy 10 precision I just got, formerly owned by NASA. Its set up with a 1hp 3ph 220vac motor, 3.1 FLA. My question is, if I should use a VFD or rotary phase converter to power it, because I’d still like to change the belt setup to adjust spindle speed and not a dial or digital interface. I have easy access to both 220 (1ph) and 120.

I would think a VFD would work if I just kept the frequency set at 60Hz? Cost isnt too much of an issue, I just like to run these as close to as they were setup to be without modification to the machine itself (ie putting a single phase motor on). This is my first 3ph machine.

Any help is greatly appreciated.

 

[johnoder]

"even so, load-motors switched- ON but not put to work actually act as extra idlers"

Going back about twenty years before Phase Perfect that was exactly the drill here - most of shop did fine on 5HP idler. When was time to start the compressor, I just flipped on the additional 3HP idler

 

[Ironcross44]

Thanks guys! Any particular brands to look for?

 

[Ironcross44]

A VFD doesn't PREVENT you using mechanical ratios. "Both" is nice.. so you can move just a skosh away from an RPM that has hit resonance that is causing chatter or vibration on some specific tasking.

Not expensive for 2 HP models. Just make sure the MAKER spec's the unit for 1-Phase input, publishes de-rating right in their manual, not by rule-of-thumb.

That said, I'd use an RPC.

They "just run", and for ages.

You'll love that if/as/when you add a mill or drillpress, 3-Phase grinder.. or ... any of many 3-phase possibilities that are better and cheaper than 1-Phase. VFD are meant to be dedicated to, and attached directly to, but ONE load-motor, so before you lnow it, you've had to buy two, then three.. etc..

RPC don't care, so long as total load is not overload, and even so, load-motors switched- ON but not put to work actually act as extra idlers.

Not a lot of point in less than a 5 HP RPC idler. Even though your SB's motor will probably start just fine on a 1 1/2 to 2 HP RPC, small ones are not common. Your SB will probably run all but the heaviest of loads on less than 1 HP's "worth" from the idler OR VFD.

Thank you! By the way, that word “skosh”, is that a midwest thing haha I just moved to Naperville from Southeast PA (Chester county), and I never heard that term used until I got out here. I love it tho

 

[BDRetz]

Huge fan of the VFD route. Currently have 3 of them and don’t plan to go to an RPC. I use the variable speed enough on my Heavy 10 that I don’t think I could work without it.

Two caveats:
Make sure you get good documentation with it so you can program it for the control switches you want to use.

VFDs often don’t play nice with GFCI circuits. If this is a concern, there are models available that are more friendly.

Hope this helps.

Ben

 

[neanderthal mach]

Nothing is ever "perfect" so there's trade offs for powering any 3 ph motor without real 3 ph line power being available. Times have changed and it's now pretty standard in most industrial manufacturing plants that do have 3 ph to add VFD's, PLC's etc for all the fine tuning and timing options in a complex manufacturing line they allow. The remote mine I worked at had compared to us basically unlimited 3 ph available and power bills of a few million a month. They had literally hundreds of those VFD'S and PLC's in the ore concentrator plant.

In a home shop with a few machines and unless you can build your own, the rotary ph converters aren't cost effective compared to any half decent VFD's. And even a free rotary ph converter can't do what they can. Before buying my 220V 3 ph. mill, good information about VFD's was a lot less common on these forums, I spent a month or two asking questions about solid state 3 ph converters, rotary's, and then the VFD's including questioning those industrial electricians at work. Due to that information I bought a VFD and I've seen nothing yet that would change that decision because of all the extra built in ability's they have. And yes when adjusting to much lower motor rpms, some type of mechanical torque multiplication is the better method. There's also a growing trend with some manufacturer's adding VFD's to there machine tools as a built in package just because of those optional ability's. And some of those manual lathes can have the VFD slaved to special DRO's to give a constant surface speed when facing just like CNC can do.If your like most, buying a 3 ph machine tool and adding a VFD will convert you instantly and show just how noisy and poor those single ph motors generally are. Today and if I moved to where I could get that 3 ph power, I'd still have a VFD on each machine.

Just don't buy at the cheapest possible price. Buy something with a recognizable brand name, Hitachi, Teco, Baldor ect. As Ben pointed out, and while the programming you want to set up is pretty easy, it takes a well written multi page user manual to properly explain how to do what you want for ramp up/down times, pre set speeds etc. If it's in Chinglish, that user manual will be almost worthless. I'd start here. https://www.automationdirect.com/adc/home/home

A couple of additional points are that most VFD's don't like any power switching between it and the motor it's controlling. If you were to add a simple 3 button start, stop, emergency stop control station, those need to be wired into the input side of the VFD and not directly to the motor. And that lathe with it's step pulley's and back gear is much like my mill with it's step pulleys and back gear. The VFD will display the motor rpm, and used at 60 Hz your spindle speeds will be the same as it's OEM placard shows. Exact spindle rpm isn't all that important, but imo it's still helpful to add a cheap magnetic digital display for what the spindle is really turning when your adjusting up or down on the motor rpm. With a fixed speed step pulley machine, tool or work piece chatter is a royal pita, being able to adjust speeds on the fly to move out of that harmonic range makes everything a whole lot easier.

 

[jim rozen]

My personal advice is that either approach will work fine. I have several machines with two speed motors, and a SB exactly like yours, run off a very modest, bare bones converter. I also have four other machines that run exclusively off small single phase VFDs - both inexpensive TECO and one off a Hitachi.

(Say if you want details of near-free, bare bones stone-age rotary converter)

Sensorless vector drives (most are these days) can maintain torque to near tick-over speed. The short answer to your question here is: either one. If you are likely to have any other three phase equipment in the future, this pushes slightly towards a rotary converter.