If you end up with a three phase Bridgeport (or any other equipment for that matter) one method of operating it on common household "single phase" is with the use of a VFD,or Variable Frequency Drive. Not to be confused with a Volunteer Fire Department - two different things. Don't get confused - the results could be bad. :tired:

Low speed torque is a problem with VFDs. In this case it is a step pulley machine so the speed can be approximated with the belt first, then fine tuned if necessary with the VFD. It comes in handy.

Depending on the HP rating of the motor and it's intended use, a VFD can be had for relatively cheap - the one in this thread was about $160 and can be remotely controlled, which will come in handy in the near future for this machine.

This is one way to mount a VFD on a Bridgeport. It may be a temporary home for it as this machine is slated to be converted to CNC within the next few months, but here's some pics anyway - might give some of you ideas.

I do not have any dimensions or even a sketch of this thing. I put it together using scrap and simply cut to fit as I went. I kinda had a plan, but I more or less designed this on the fly.

It was made from a piece of 4" aluminum angle, a piece of 1/4" AL plate and a piece of 1/8" AL sheet - all scrap sized pieces. All of the material was cut on a 14" miter saw with an 80 tooth carbide tipped blade. It was all rather sloppily TIG'd together - some of the material was in rough shape and should have been acid etched prior to welding.

If this was a final installation, the wiring would have to be covered and secured and so forth - but for now it is good to go until the retro-fit. Only the safety grounds are hanging out but you will notice there is no strain relief on the cables. It was mounted direcly to the belt housing with 4 #10 tapped holes in the housing. The shield on the right of the VFD is to keep belt dust out of the VFD. The belt and pulleys create a nice, gentle breeze which will help keep heat build down.

This is a single phase installation as you might be able to see by the 3 prong plug mounted to the pole behind the mill. I ran wires for the third phase but I will likely leave this the way it is. Undecided.

There is another thread about the mill here:

http://www.cnczone.com/forums/showthread.php?t=10535

And another thread about the shop in general:

http://www.cnczone.com/forums/showthread.php?t=14398

Enjoy the pics, guys.

Scott

You are the man!!!!

Keep it up!!!

Ok, fess up. You didn't really buy a new VFD for a mere $160 did you. If so you must tell us.

Very very nice install. I'm inspired to do the same with mine, whenever I get the time.

Good idea, Scott. I had a similar idea for one of my mills when I replaced the original motor with a new one that had a foot mount bracket on the motor frame, as well as having the C-face flange. Since the foot mount was stuck up there doing nothing, I cabbaged my VFD bracket onto that. :)

Ok, fess up. You didn't really buy a new VFD for a mere $160 did you. If so you must tell us.

http://www.driveswarehouse.com/Drives/?cPath=149&filter=1&accessories=&products_id=&categories_id=&manufacturers_id=10&prop_3=1&prop_6=&prop_10=&x=24&y=9

Hopefully the link works. They list it now for $210 - Hitachi model #L100-007NFU. The NFU stands for "Not Screwed Up". Don't get the AFU model....

:D

I recall paying right at $178 with shipping in January of 2005.

:wave:

Scott

Any info on the paint you used for the BP? How did you prep it? Was it completely dissassembled?

Thanks,
jW

Look at post #21 in the following thread -
http://www.cnczone.com/forums/showthread.php?t=10535

I will also scare up a pic of the paint - update - it's attached.

Yes - the thing was torn completely down and stripped to bare metal, pressure washed, sanded, filled, sanded, filled, sanded, filled.....then primed and painted piece by piece. It took about a month to have it back in one piece.

My advice? Remove only the loose filler and clean the crap out of everything then fill only the areas you need to, blending back into the factory fill. The filling process can get expensive quick since the rough casting is exactly that - rough. If you want it smooth and you take it down to nothing like I did, you will probably use at least 1 or 2 gallons of filler and spend a lot of time covered in dust.

Scott

Question? Are you going CNC with this guy or are you staying with cranks?

If you are going CNC you are going to want the VFD as close to the PC as possible so you minimize the potential for noise getting into the system. This assumes you want the spindle speed under computer control. That means the VFD goes in the control box and the control buttons & such go on some kind of remote panel mounted right where the VFD is now.

This is THE most pristine machine that I have EVER seen!!! Very nice work on the machine AND the shop.

Best,
-jd

OH. What's under the cloth?

Not sure which pic you are asking about - one pic is where I was drilling and tapping the mounting holes for the bracket - the rag is keeping chips out of the pulley housing. In another pic - in the background there is a tool grinder covered with a rag. Was that the question? i am a freak about keeping stuff clean - except when I am in the middle of something - then everything is everywhere...

As far as the CNC of the mill? Yes - I am going to CNC the thing. In fact I came on here after making progress on the first bracket for the X axis. I came on to post the first progress pics in many months.

The link to the write up/progress log for the conversion is listed above in post #8.

Thanks for the comments, JD. I have been spot checking your progress, too! Thanks for the tip about the VFD. I am not sure I understand - it seems like the noise would be worse by putting the VFD near the controller - or am I not thinking straight?

Scott

Hi Guys,
I am new here, but I noticed the awe at the
$165.00 VFD. Well let your jaw drop... Check out www.automationdirect.com they have 1hp 230 volt drives rated for single phase input / 3 phase output for $125.00. I am in the automation business and buy a lot of stuff from these people, they are great to work with and ,unfortunately for me (ha ha) will sell to anyone with a credit card. I just got a 1 Hp Bridgeport series 1 and needed 3 phase for it. These little drives are great for machine tools, they have input options for start/stop forward/reverse and even a jog (bump) feature as well as the variable speed, they make life way to easy. I hope this helps some with the costs.

Robin

O.K.
Now i can stop spending sleepless nights wondering what color to paint my gantry router when its done. Awesome job!

Hi Guys,
I am new here, but I noticed the awe at the
$165.00 VFD. Well let your jaw drop... Check out www.automationdirect.com they have 1hp 230 volt drives rated for single phase input / 3 phase output for $125.00. ......Robin

Thanks for the link - you just saved a buddy of mine some cash!

Have you used one of these brands before? Any history?

Scott

Scott,

I have used many products from Automation Direct and all have exceeded the quality for the price I would expect. As for their VFD's, I have used about 15-20 of them for various applications, mostly pumps and fans, and a couple for 3 phase conversion. The one I mentioned I am using on a Bridgeport step pully series 1 machine and have had no problems for the 3 months it has been in very light use.
A couple of things to keep in mind about VFD's in general...

1) Check the ratings if you are going to use it to make 3 phase out of single phase. Specificly check that it is rated for the horsepower you need if it is fed with single phase. Most VFD's are only speced with 3 phase input. A good rule of thumb is to oversize the drive by 2 times if it is not rated for single phase input. This has to do with the input rectifiers in the VFD. Ignoring conversion losses the single phase input current will be 1.73 times higher than the 3 phase input current, so 2 times gives some margin. Best is to check with the VFD manufacturer to be sure.

2) When using a VFD on any motor for speed control be aware that the cooling of the motor is dependant on the internal fan on the rotor. When you slow a motor down cooling air flow goes down with the speed of the motor, normally by a factor of 4, IE 1/2 the motor speed = 1/4 the air flow. I use a rule of thumb that I will not slow a motor to less than 1/2 of full speed - period, and I have gotten into trouble at this setting for heavily loaded motors. These are some things to think about. Input from others appreciated and welcomed, good or bad.

Best wishes,
Robin

While I haven't purchased any of their vfd's before, the motors and other bits I've gotten from automation direct were all great. No problems w/ anything.

I have used Automation Direct for years and have always been satisfied with their products and thier prices (PLCs, VFDs, sensors, etc). I have a 2HP GS2 VFD that I have been using on my Bridgeports for a number of years and it works great. I like the remote face plate which can allow you to hide the VFD away from dust, chips, coolant, etc and just mount the face plate somewhere close to the front of the head. Just run a ribbon cable from the face to the VFD an you are in business. These are really ease to set up and change parameters on the fly.

--Eric

The one shown in this thread is a Hitachi. The Automation Direct units seem to have all the same features for less cash. I am wishing now that I would have seen the Automation Direct units before I bought the Hitachi. Hindsight......

Thanks again for posting the link, RDFeil - and thanks for the posts, guys! This is the kind of info that makes the Zone what it is.

I will spend more time looking at Automation Direct's inventory in the future - I don't think I even knew they carried VFDs!

:wave:

Scott

There are only a few VFD manufacturers and they package them different for OEM applications. Automation Direct does not make their VFD.

Those are some good prices on VFD's even if they are made in China. I guess I'm still used to the prices on VFD's from about 15-17 years ago, expensive. With those prices I'm seriously considering getting my big lathe up and running at home. 10 years of sitting in the garage is way to long and I've missed it.

New guy here. I'm looking at buying a Series 1 Bridgeport and I was wondering if I could use a VFD in place of a rotary phase converter? BTW, very nice machine!

Chris

Yes
You can get a single phase input three phase output VFD and it will run your mill, it will also give you the added benefit of being able to vary the spindle speed. You however can only run one motor at a time from a VFD so if you have quite a few machines a rotary converter may be better.
Hood

Hood,
Thanks for the info. Is there some more info on this so I can do some homework. I was going to look into size and brand. I was looking at a Bridgeport 1.5 HP, 3PH. Any suggestions on where to get good quality VFD's
Thanks again!
Chris

I am from the UK so really cant be of any help to where to get one I am afraid. As for size you can use a larger rated one but oviously not smaller. I got both of mine from eBay and they are both 5 HP, I use them on a 2HP bridgeport (one as spare) I have 3 phase power so mine are 3 ph in/out but you will have to make sure you get one that is capable of running from single phase.
You might find some usefull info here http://web1.automationdirect.com/adc/Technical/Catalog/AC_Drives_-z-_Motors

Hood

Any suggestions on where to get good quality VFD's
Thanks again!
Chris

There are a few good links right in this thread......