Need Advice/Help with PC for lathe

Guys I really need your help and suggestions. I am phase converter stupid(read that as absolutely no knowledge). I just purchased a SB Hvy 10 with a 1hp 3 phase GE motor with 56 frame and 3/4" shaft. I am disabled and on very limited income(especially seeing as I haven't sold my other lathe yet) and do hobby gun work mainly for myself. I have no way of acquiring 3 phase power in my part of small town I live in.

I inquired with the local electrician and they want $400+ tax, plus installation for a 1hp VFD converter? I find a 2hp compatible on Ebay for $179? My questions, is the $400 really out of line? Is a VFD much better than a static PC? Am I better off going with a converter or buying a new single phase motor replacement? Lathe is in super shape and was bought at a state college auction. It was sold off location so I have no idea of present motor condition and can only assume it is comparable with lathe condition!!!!

Read through several pages here and am really more confused as I was trying to combine bits and pieces from different threads to adapt to my situation and finances!

I can really use some help, guidance, recommendations on what, where to buy and how much. Thanks much in advance.

Respectfully,
Dennis
Lemmon, SD

Dennis,

I read your posting as you have a frame 56 motor with a 3/4" shaft. although this is possible it is not at all common. A frame 56 motor should have a 5/8" shaft and the obsolete frame 66 motor had a 3/4" shaft. I know it is possible to have a 56 frame with a 3/4" shaft as I do have one but they are rare birds.
If you do indeed have a 3/4" shaft then you will have a hard time replacing the motor with a single phase motor as no current frame sizes have 3/4" shafts. You would need to replace, or bush, the pulley or perhaps you could find an old frame 66 motor in single phase (not likely though)

this leaves you with the challenge of running the 3 phase motor. YOu have basically 3 choices here.
1. use a VFD
2. use a static phase converter
3. use a rotary phase converter

I personally detest static converters when you can get a TECO FM50 VFD for very little more than a static converter and it is much better. You would need a single phase input, 3 phase output, 230 volt model. there are many other VFD as good or better than this one. I just picked the cheapest one I know of. It is not difficult to wire up and you could wire it to the lathe and put a cord with a plug on the incoming power side then just plug it in when you want to power up the VFD. I prefer to have a switch before the VFD but you could get by with only a cord. This way you would not need the electrician.

The simple way to install is to wire the VFD output directly to the lathe motor and bypass all the orginal switches. Mount the VFD at a convienent location on the lathe and use the VFD start / stop and speed controls. If you have a drum switch on the lathe you can use it to control the VFD with just a little more wiring and this would allow the lathe controls to function as they orginally did. I have a details for this hookup for The TECO FM50 and for a Hitachi SJ200.

The rotary phase converter is a little more work and is not really needed for just one 3 phase machine. The simplist versions of these would be a knife type disconnect switch, a 3 phase motor, about 2 hp, a potential relay and a start capacitor. I can provide more details if you really want to pursue something like this. I would prefer the VFD setup for my own use.

toolnut- Thanks for time in responding. Once again I should have actually used a caliper instead of 'thinking' the shaft looked to be 3/4". After your info I grabbed a flashlight, the caliper and stood on my head and actually measured. Shaft is indeed 5/8". That is why these forums exist, to help us lazy uneducated wanna be's!!!!!!!!!

I am a local support your small town kind of guy but with my income I find it pretty darn hard with current economics to pay $400+ tax when I could buy a like or similar item for less than 1/2 that amount?????

Where is the best place to buy the smaller VFD's? I have heard of slow starting etc with these conversions, is this a big problem and inconvenience for lathe operation?

My Craftsman has an Allen Bradley BUL 350 drum switch. This SB has a Cutler-Hammer switch mounted with 'Start', 'Stop', 'Reverse' on it. Is this another form of "drum switch"? It has a huge panel mounted in the rear (5+" deep, and roughly 13x15" and marked Sylvannia. Electrician stopped and looked things over and stated it was for reversing the 3 phase motor. Cannot remember what he called it but it has a 110V transformer he said that operates the C-H switch??????

Sure can use some help, suggestions on what where is the best place to obtain a VFD? if that is best and what they cost rougly? Thanks again toolnut.

Respectfully,
Dennis

Solutions

The VFD is an elegant non-mechanical solution- you wire the motor direct to the VFD, put the drive in some midrange belt position, wire the drum switch controls to the VFD's forward-stop-reverse terminals, hook your 240v single-phase power leads (red and black) to the VFD's input terminals (there's three, so one goes unused), and when you flip the drum switch, the VFD's speed-control runs the motor at whatever you want. VFDs also do dynamic braking and reversing control, so instead of switching motor leads around, your drum switch simply gives the VFD commands, and it does the rest. Search the E-sites for VFD... look for 200-something input, and 2hp output- that'll give you plenty of power, and enough headroom to run a three-phase drive on single-phase input. Surplus VFDs in this class can be had anywhere from $70 to $150 with very little searching. I used two Allen_Bradley 1305s (model AA08A) on my J-head mills... think the more expensive find was $120.

An RPC or static converter is a 'brute force' method... and it works, and they're not hard to build, but the result compared to setting it up with a VFD... no contest... the VFD is just too nice... but if you have a decent idler motor, and a junk-box with a fair selection of odd stuff, you can MAKE an RPC on the cheap.

You could also just find a single-phase motor to swap in... my feeling is that it won't be nearly as smooth as a 3-phase, but you'll hafta make that judgement for yourself.

My recommendation is to go VFD, but do what you feel comfortable with. Also, never end a sentence with a preposition!

1) possibly the most important issue here is to be honest about your ability to perform
electrical wiring. No matter what solution you choose you will be dealing with electricity
and if you are setting the machine up it has to be safe and workable. So if you cannot
do that you need to somehow bite the bullet and either educate yourself on this matter
or get somebody who can do it. This is something you cannot finesse - read up on it
or get somebody who can guide you.

2) choices in no particular order are:

a) replace three phase motor with single phase motor.

b) install static converter

c) install VFD

d) build and install rotary converter.

Each one of these entails different amounts of physical labor and financial outlay.
Because you are limited in both you cannot trade one off against the other. Some are
more technically challenging than others.

But first you have to recognize that no matter what choice you pick you will have
to be acting as an electrican and you have to be comfortable with your skill level
at that. This would be true even if you happened to have utility three phase
power on site.

In that case having an electrican show up to do the installation would run at about
100 bucks per hour plus whatever the components cost. To put this in perspective,
the most expensive parts of my rotary converter which runs my 10L are the wire
itself, the receptacles, and the plugs on the cord drop for the machine. Probably
a hundred dollars right there, retail.

Listen to what folks say here and get a cross-section of opinions.

Jim

Dave- Thanks a bunch for the info. I had heard of the 3 phase being a smoother ride over single for chatter etc on some lathes. Sounds like the VFD is my simplest solution. An RPC is really not an option whether store bought or home built as I only have a 14'x12' room for lathe, reloading benchs, etc. Cost was my biggest concern and where to buy. I am certainly open to the option of having an electrician wire in the unit. My cost concern was for the $400 VFD and best place to purchase.

On my income paying double for a $50 item is one matter, having to pay double for a $200 item is quite another. That extra $200 is my gas bill for Doctoring the next 2 months at today's prices.

As for the prepostion comment? English wasn't my strong suit in the early 70's and high school so 'which' sentence and 'what' word/words blew over my head now as it did then .


Jim-Thanks also for your very understandable comments. My 3 phase experience is nonexistent. I was in the LP business and did HVAC service work for 19+yrs before having to quit work. My experiences with 24, 110 and some 220 is adequate. I have rewired half of an older house I had, wired my current work room, wired a 28'x56' barn I had on a past hobby farm but know nothing on the hows/why's of 3 phase. Also am mostly self taught in LP heating unit repair/replacement, sheetmetal, carpentry, welding, engine building, minor plumbing, gunsmithing work and except for a couple weeks in a machineing class in high school have learned everything hands on with 5 lathes I have currently owned or own now. So I usually can figure things out. As stated hiring an expert to wire is certainly an option as I am not willing to see if my current pacer/defibrillator is 3 phase compatible.

Again Thanks Dave and Jim for your much appreciated info. Any more suggestions on where to look? I am 200 miles from bigger cities such as Rapid City/Aberdeen/Pierre, SD, Miles City, MT and only 140 miles from Bismarck, ND so not many electricians or electrical supply houses so was wanting website info etc for pricing. Thanks again.

Respectfully,
Dennis

Factory Mation has brand new 1 HP Teco FM50 VFDs very reasonable. You can get one that runs off 120 VAC single phase for $120, if that is all you have available, or one that runs off of 240 VAC single phase for $119 if that is in the shop. You will be very happy with either one.

sgunsel- Thanks alot for the info. Do you have a website link? I have 220V wired into my work room and that is what my current Craftsman runs off of. I am really looking for some web links for pricing. I tried Grizzly and they only have static and rotary that I could find. Also Enco had nothing I could find. Went to my old workplace and looked through Granger who had nothing and Johnstone had a very limited listing with more high end items.


Talked with a motor shop yesterday and he informed me they are relatively easy to wire in.

Any other help out there??? I sure thank those who have responded for their time.

Respectfully,
Dennis

If you are comfortable doing wiring then in principle you
could construct a simple phase converter from a large
(3-5 hp) three phase motor. They can be very simple and
still perform quite well.

The total cost for something like this can be not much
more than the cost for the wire and wiring devices. But
it does involve a bit of heavy lifting if you are disabled.

Jim

Look at:
www.factroymation.com, has TECO
www.automationdirect.com, has their own brand
www.driveswarehouse.com, has Hitachi, Polyspede and others

Stay away from any VFD described to be a "fan and pump drive" These are the cheapest but are not good for machine tools.

I have used, or helped to install, Hitachi L100s (now considered obsolete), Hitachi S200s, Hitachi SJ200 (a very good sensorless vector drive but you do not really need it), a TECO FM50 which is a relaible and inexpensive drive (works good with a drum switch but a pain to use with 3 wire control push buttons), Reliance SP500s (which I am currently using in my shop but they are now obsolete since Rockwell Automation bought Reliance), Toshiba S7 (the current model Toshiba would be a good drive also), Reliance GV3000 (A dang good drive but much too expensive for your application), and an old Allen Bradley. Any of these are straightforward to install with the Reliance having the best manuals. The Hitachi has a good manual as well as the Toshiba. The TECO FM50 manual is not as easy to use but it does contain the information needed and with perserverance you can install it to suit your wants.

Factorymation has the Teco FM50-201-OC for $119 as mentioned in another response
DrivesWarehouse has the Hitachi SJ200-007NFU2 for $225.
These two numbers should bracket the range you will be looking for.

Here is a connection diagram for a TECO FM50 with a external potentiometer and a selector or drum switch used to control the VFD.

Jim and toolnut I sincerely thank you for your time. It is appreciated. Jim, I don't really have any room for a rotary type whether home built or store bought. Trying to figure out how to keep my Craftsman also in the room I got as I just rebuilt it last summer and it looks nearly new now Kind of a want vs. need deal as I don't NEED 2 bigger lathes.


I am real excited about getting the SB setup as I have been looking for an affordable quality lathe for over 10yrs and there isn't much descent affordable to me machinery in this part of the country. This unit must be mid 70's and easy 90% condition I would think with no visible wear on bed or lead screw, just some paint wear, a few scratches etc as were the other 2 Hvy 10's, the 10K and an older 48" unit at this sale. All were in unbelievable condition. Price on mine with 3&4 jaw, about a 6" and 10"(haven't measured them) face plates, steady, follow, centers, lantern tool post but no toolholders etc. This for $1872 with tax. Sound like a fair price?

toolnut- I sent you a PM. Hope that is acceptable?

Thanks again and a super weekend to all.

Respectfully,
Dennis