Clausing 5914 phase converter choice

[swarfie]

I just bought a Clausing 5914 lathe. I would like to get it up and running, but I only have single phase power at my house. I want to use the vs drive as is. What should I go with for a phase converter? I’m not really keen on a rpc, due to cost and noise. If I use a vfd, can I just use it for a straight phase converter, i.e. just send the 3 phase to the machine and use as is? Or do I need to use it to control forward, reverse and braking? How about a static phase converter? Or something like this:

https://www.amazon.com/Single-Conve...mzn1.fos.f5122f16-c3e8-4386-bf32-63e904010ad0.



I know this has been beaten to death, but I am having a hard time finding a direct response in the postings.



Thanks all!

 

[Joe Gwinn]

I use Automation Direct. In 2018, I bought a model GS2-23P0 for $309, when its predecessor just died. No problems.

 

[swarfie]

Hi Joe,

Thanks for the lead. That particular model has been discontinued, but it's replacement is actually cheaper! So with this you were able to use the lathe's forward/reverse, and not the vfd's?
Thanks.

 

[dalmatiangirl61]

Pretty sure using a vfd will require bypassing all your current lathe controls. If you want to leave your lathe as-is your choices are static converter, rotary converter, or Phase Perfect. No mention in your first post of voltage or Hp.

Edit: Don't know anyone using one of those Amazon units, might want to stick to something better known. I know 2 people with Phase A Matic static converters, one uses it direct to his machines, and has been doing so for 20 years with few problems, other uses it to run an idler which powers his shop, both are just hobbyists. I run a rotary, but also run more and larger machines than the 2 with statics. I'd love a Phase Perfect, cannot justify the cost.

 

[lazz]

On my 5914 I wired the forward / reverse switch to the VFD's forward / reverse. It was kinda sketchy using small wire in place of the old heavy gauge....

The only real complaints I have with a VFD is on the Fuji GE VFD I have, if the forward / reverse switch isnt in the off position the VFD will not boot up...
And if you change the variable speed on the lathe too fast it will also error out the vfd...
this wiring method makes it look like it can plug reverse


After 14 years of no power problems I guess it could be called a success.

Because the lathe was the first 3 phase machine I installed a VFD. My second machine was a mill... it has a built in 3 phase power feed which means 2 vfds.... I went with a rotary converter. In the time since I have added 3 other machines all connected to the rotary....
Had I thought it thru in the beginning I would have just started with a rotary....

 

[Dave Riant]

I just bought a Clausing 5914 lathe. I would like to get it up and running, but I only have single phase power at my house. I want to use the vs drive as is. What should I go with for a phase converter? I’m not really keen on a rpc, due to cost and noise. If I use a vfd, can I just use it for a straight phase converter, i.e. just send the 3 phase to the machine and use as is? Or do I need to use it to control forward, reverse and braking? How about a static phase converter? Or something like this:

https://www.amazon.com/Single-Converter-MY-PS-3-200-240V-Should/dp/B07F26M1TH/ref=sr_1_1?crid=3IU6U9U5QEC2A&keywords=dps+2hp&qid=1677875797&sprefix=dps+2hp,aps,88&sr=8-1&ufe=app_do:amzn1.fos.f5122f16-c3e8-4386-bf32-63e904010ad0.



I know this has been beaten to death, but I am having a hard time finding a direct response in the postings.



Thanks all!

 

[Dave Riant]

The 5914 had options of 110 and 220 Single Phase. I swaped out my 3 phase for single phase 20 years ago and it's worked great. The manual has wiring instructions. Dave

 

[JST]

If you want to use the original controls, you will have to use a considerably larger VFD, or opt for a Phase Perfect.

The turn-on surge of a motor is 5 to 7 x the full load current, as a general rule, and most VFDs can only handle rather short overloads to perhaps 150% of normal. Therefore, you need to oversize the VFD by a factor of 4 or 5 in order to start a motor with a switch, vs the size that would operate it fine using the VFD to do start-stop.

 

[swarfie]

Wow! Thanks everyone for your input. My only experience with an RPC was many years ago, and it was noisy as all get out. I guess that is no longer the case, so I will need to rethink those. The lathe has a 2hp, 230VAC motor, btw.
Looks like I still have much homework to do on this before I make a decision!

 

[dalmatiangirl61]

Wow! Thanks everyone for your input. My only experience with an RPC was many years ago, and it was noisy as all get out. I guess that is no longer the case, so I will need to rethink those. The lathe has a 2hp, 230VAC motor, btw.
Looks like I still have much homework to do on this before I make a decision!

Might be the condition of the bearings, with good ones they are quieter than with bad ones, but not whisper quiet unless you put it outside or in a soundproof box, that is the main reason I'd like a Phase Perfect converter. Do you plan on buying more machines, maybe with larger HP? General rule of thumb on rpc's is 2x the motor HP, since there is no 4Hp version, a 5Hp rpc would cover your needs, and you can run multiple motors with just 1 unit. If you go vfd route, each motor needs its own vfd.

Static converters do work, and they are silent, but you lose HP, depending on who you listen to, it ranges from 1/3 to 2/3's of motor rating. Now that I've mentioned them, others will be along shortly to tell you all the reasons not to get one

 

[rons]

At least they are trying for a little honesty, "The failure rate is very low".

 

[hkinkade]

I have had this setup for more than 10 years. The Teco VFD only acts as a phase converter. I have it set for soft start, in-rush current is not an issue with softstart. It works exceptionally well. The speed is adjusted by the lathe via its variable drive unit, as originally designed. Forward and reverse switch of lathe changes the the vfd signal accordingly. So bottom line, the VFD is just a phase converter and provides a nice soft start. The lathe does everything else per it's original configuration. The vfd does not need to be oversized with this approach.

 

[JST]

That approach works, sure. It drives a single machine at any given time, although it could in principle run more than one single machine in a shop.

The oversize is for essentially substituting a VFD (used as a converter) for an RPC, in cases where one or more machines may be used at a time, and where it is desired to operate with the original machine controls.

 

[hkinkade]

I understood the original post to be specific to a single 240 leg and piece of equipment. Yeah, you could have the
VFD sized for the current capacity of the branch and then split it off to multiple machines, but then it may create some challenging separate protection legs downstream and you loose the benefit of soft starting and reverse rotation by individual machine selector. In my case, and I thought that of the origijnal post it was one circuit and machine.

But you got me thinking about how to deal with multiple legs of three phase off a single branch.

 

[JST]

.......................... Yeah, you could have the
VFD sized for the current capacity of the branch and then split it off to multiple machines, but then it may create some challenging separate protection legs downstream and you loose the benefit of soft starting and reverse rotation by individual machine selector. ........................

I may not be understanding your point, but I don't see the problem.

You would size the VFD for the starting load of the biggest motor, plus whatever else may be running at the same time. The starting load can take into account the short term 150% overload that most VFDs allow, which may be allowed for some time between 10 seconds and well over a minute, depending on the VFD. Larger VFDs may be slightly different as far as overloads and times.

The ordinary machine controls would be used. Start, stop, reverse, etc. Just like a machine on an RPC. There are a number of folks here who have stated that they do exactly that.

The machines are generally intended to be connected to a higher capacity power line, and should have the appropriate protections internal to them (for industrial machines).

Soft start is possible to add, if desired, but since many industrial machines use a clutch, the number of starts may be low enough not to bother.

Reversing etc is normally part of the machine controls as well, for any 3 phase industrial machine that needs to reverse.

 

[hkinkade]

JST - I’m certainly in agreement with what you have stated.

I’m coming from a home shop perspective and experience. My comment on protecting each branch is moot if that equipment has the proper protections independent of the main branch. But you know this. The reason I bring it up is many small shops and home shops don’t have individual protection of motor driven devices and even the circuit may not protect the device. These shops are often setup with minimal electrical knowledge. I’ve seen this often and felt it was important to elude to this issue. As always your input is extremely accurate and professional.

 

[piedmontg]

I have had a TECO vfd on my 5904 for over 20 years. This is the second one as the first took a real bad power hit and it was gone. It is a little over powered but it was a spare I had. As for the control wiring just use the drum switch to control the VFD, ie its control wires, get fwd, rev no problem. I use my hydrolic control but can fine tune easily with the VFD, especially in back gear if I want to go real slow. I have a 10HP American Rotary also. I have a number of tools that do not get used very often so they ar run with the RPC, while the others with VFD's. It is just quieter in the shop without the RPC running, and my other tools that use a VFD take advantage of the speed control option. I have a master control panel that I can wire to suit the speicific tool, all tools have a Fuse Box that can switch off the power. The entire control panel is like a magnetic starter, if power drops all power to shop tools drop, so if it comes back on nothing is running. A bit of a pain the shop needs to be turned on each day, push a button. I strongly recommend working with an electrician. I was fortunate to have a friend who designed electrical systems for manufacturing plants.

 

[Skipnvix]

I, also just picked up a 5912 clausing with 3 ph motor. I’ve been on the fence on this issue. I do believe that the VFD is the right choice, so if the hydraulic speed control doesn’t cooperate I’m still good!

 

[BT Fabrication]

its only a 2Hp motor, those can be bought cheaper then any VFD can........

 

[G-ManBart]

I, also just picked up a 5912 clausing with 3 ph motor. I’ve been on the fence on this issue. I do believe that the VFD is the right choice, so if the hydraulic speed control doesn’t cooperate I’m still good!

Not really. The VS system will revert to the lowest speed setting if something fails. When people convert Clausings with the hydraulic VS system to VFD speed control they have to change the drive pulley/belt combination to get the RPM in the correct range for the VFD.