Have 3ph, need speed control. Does this effect VFD choice?

[Trunk Monkey]

...my situation is a little more complicated than the title. I don't have that much experience in this area so please correct me if I've missed anything pertinent.

I want to set up a home shop using some existing 3ph equipment. The largest determining factor on what power equipment I buy is determined by how I will power the lathe. I'll need an RPC regardless, just not sure if I need one big enough to power the lathe.

Lathe is a Lodge & Shipley 2013-AVS (larger machine purchased mostly for the generous 2.5" spindle bore). The lathe was previously modified to eliminate the DC motor as well as the complisticated analog variable DC speed control that was probably pretty snazzy when the machine was born in 1969. Machine was last used in a production shop for a single op at a fixed RPM. RPM was one of 3 speeds selectable from the gear box after the 7.5hp 230/460 3ph AC motor was repurposed to drive the gear box directly.

Is there anything I need to consider when buying a VFD for speed control only (no concern for phase or voltage conversion)?

Additional info:
- I also have a 3ph Bridgeport that needs power.
- I would also like the option to have 3ph power on tap to run any other 3ph equipment that I may find in the future, it's likely that none of these will have a larger motor than the 7.5hp lathe.
My RPC plan is to build a dual 10hp motor RPC. I have a nice 10hp motor currently and could easily double capacity in the future with another motor if I need to.

How I power the lathe will decide how large of an RPC I'll need form the get go. I can either run my RPC's 3ph to a lathe VFD combo or I can run 230 single phase to the VFD and leave the RPC out of the picture. The latter route would allow me to run a lower capacity VFD.

Is there any advantage to running the later at 460V vs 230?

Finally, can someone recommend a good VFD for the this lathe?

 

[Overland]

You can run a 7.5 hp 3-phase motor directly from 220v single phase with a VFD.
The motor will need about 20 amps, 230 volt from the VFD, for 7.5 hp.
I've had a lot of success with Fuji. They have a rating table for VFD's supplied with single phase, attached below.
I would suggest their FRN0033C2S-2U, rated at 19 amps when supplied from single phase.
Easy to install. Wire VFD output directly to motor, eliminate all contactors from the circuit.
Good luck,
Bob

VFD, 10hp, 230VAC, 3 Phase, 33A, Compact Micro Dri

VFD, 10hp, 230VAC, 3 Phase, 33A, Compact Micro Drive, Easy To Use (Optional NEMA1 Kit # NEMA1-40E2-24 Available to Order Separately)

www.wolfautomation.com

https://americas.fujielectric.com/wp-content/uploads/2017/09/Frenic-Mini-C2-Single-Phase-Ratings-FECA-AN-175.pdf?r=false

 

[mksj]

A VFD for the most part is not a plug and play 3 phase conversion power source for multiple machines, and the controls/parameters/programming are machine/motor specific. If you have 230VAC single phase coming in then you would want to run all the machines at that voltage, vs. having to step up the voltage for a single machine if it can be run on either 230 vs. 460VAC. A 10Hp RPC will not be large enough to start a 7.5 Hp motor, more like a 15 Hp RPC would be needed (but staggered RPC 10Hp motors would work but more noise and complexity). If you decide to use a VFD on your machines, you need to decide if the power feed to them will be 3 phase or single phase, as this effects the size VFD you would need, it is not a simple install, as the VFD output is directly connected to the motor, and not a machine power source. So you need to factor in cost of controls and safety interlocks.

If you want a power source of 3 phase, then you could use something like a Phase Perfect as a 3 phase power source for all your machines, their idle power is around 100W. If you want variable speed on your larger lathe you can then use a 3 phase input VFD, you will save some costs in the VFD if you can feed it 3 phase, if single phase input (on a 3 phase rated input VFD) typically you need to at least double the VFD size and may need a DC choke. Many of the newer VFD's require significant derating when running a 3 phase input VFD on single phase. I do quite a few VFD systems using the Hitachi WJ200, they have been reliable, reasonable cost and pretty straight forward to install. An RPC, although provides 3 phase, there is still some derating factor when using it to power a 3 phase input VFD so I would go up one size (or increased output current headroom by 10-25%) on the VFD rating when using it with an RPC.

Invertek VFD's do have native single phase input VFD's for a 7.5Hp motor, they are pretty easy to install, but are more expensive then something like the Hitachi or Fuji VFD's. They are a simple solution, but you are getting into the price range of the Phase Perfect Simple phase converters.

7.5HP 230V Digital Phase Converter - Phase Perfect® Simple

7.5HP 230V Digital Phase Converter - Superior to a 15HP rotary

www.phaseperfect.com

Hitachi WJ200-075LF if 3 phase input power, WJ200-110LF if single phase input power for a 7.5Hp motor.

WJ200-075LF

www.driveswarehouse.com

WJ200-110LF

www.driveswarehouse.com

Invertek ODE-3-420240-104A 5.5 kW (7.5 HP), 24 A, 200-240 V, 1-3PH is rated for single phase input power

ODE-3-420240-104A

www.wolfautomation.com

 

[JST]

People do run their shops off of one VFD as a "cheap Phase Perfect".

However, the VFD is normally a large one, rated to handle the largest motor start in the shop, plus any other machines running at the same time. And, of course, derated to handle the single phase source.

Does that make sense? It can, depending on what budget you have available, what you can buy surplus, and what you want.
\
One thing it does NOT provide is speed control, since all the connected machines get the same output, so all run at the set speed. Normally that is not what you want.

The OP states in the title that speed control is needed.

 

[jim rozen]

"A VFD for the most part is not a plug and play 3 phase conversion power source for multiple machines,"

That's NOT what he's after, read his post: he's planning on a dual-motor rotary converter setup, the question was specifically about variable speed capability for one particular lathe.

 

[mksj]

"A VFD for the most part is not a plug and play 3 phase conversion power source for multiple machines,"

That's NOT what he's after, read his post: he's planning on a dual-motor rotary converter setup, the question was specifically about variable speed capability for one particular lathe.

Maybe you need some glasses, so you can read past the first line. If you have something constructive feel free to add your input as to your recommendations. I have outlined options and specific VFD models depending on his 3 phase source which is what he asked. I do not see that you have contributed anything to this post.

Additional info:
- I also have a 3ph Bridgeport that needs power.
- I would also like the option to have 3ph power on tap to run any other 3ph equipment that I may find in the future, it's likely that none of these will have a larger motor than the 7.5hp lathe.
Finally, can someone recommend a good VFD for the this lathe?

 

[Overland]

I thought I covered it fairly well.

 

[Trunk Monkey]

Thanks for the input so far, I've taken a quick look at most of the info link provided, I'll digest it a little more thoroughly this evening. The Phase Perfect looks nice but $$ and still doesn't provide speed control for the lathe. Here's a more simplified breakdown of my needs, probably should've added this to my original post for clarification as I realize I may have muddied the issue by also explaining why I need what I need (the lathe is a bit of an oddball powerwise).

The only part of my power conversion items I currently posses are a single 10hp motor.

All options begin with native 230v 1p source

Option 1
10hp RPC to power Bridgeport and whatever other additional 3p equipment I might buy in the future
Additionally, VFD to power and provide speed control 7.5hp to 230/460 lathe (230 1p in and 230 or 460 3p out)

Option 2
dual 10hp (20hp total) RPC to power above equipment list but with RPC providing 3p input to lathes VFD
My thinking with this was that a VFD used for speed control only (no 1p to 3p conversion) might be simpler/cheaper

Option 3
Whatever somebody smarter than me suggests that meets the needs outlined above in a better way that I have come up with so far.

Is there any advantage to running the lathe's VFD at 460v vs 230? Obviously, the motor will run cooler but my concern was more for the VFD current output being halved and possibly providing some advantages for the VFD.

 

[jim rozen]

Probably best to go with the 240 volt VFD. You'd need to investigate a step-up transformer and a more expensive 480 volt VFD. There may be some advantage to using a three phase VFD but that would mean starting the idler(s) to use that.

 

[Trunk Monkey]

Probably best to go with the 240 volt VFD. You'd need to investigate a step-up transformer and a more expensive 480 volt VFD.
- So a VFD that does 240 1p to 460 3p is generally more expensive? Why the need for a step-up transformer?


There may be some advantage to using a three phase VFD but that would mean starting the idler(s) to use that.
- Yes, any option that includes 3pinput power to the VFD would require an RPC.

 

[JST]

The point of the 3 phase converter, of any type, is that it can power the other machines, and can also provide 3 phase to the specific machine speed control VFD, as well. That does have the advantage of allowing a wider range of VFDs, since you do not need one that can accept single phase input.

You are going to power the other 3 phase machines anyway, so that adds no extra stuff, and the wider choice of 3 phase input VFDs means you can probably get what you need at lower cost.