# Need help with a VFD for my mill



## melsdad

Guys I am looking for some help to power my 2hp 3phase Kent KTM 380 mill. My electrical skills are limited but I can get help from a friend who is an electrician.  

 I am planning to use this VFD Hitachi WJ200 015SF Variable Frequency Drive 2 HP 230 Vac Single Phase Input | eBay

I would like run the VFD remotely. The drive will be mounted in a control box on the wall, with a small control box mounted on the mill that has a pot, e-stop, and forward and reverse buttons, and possibly a coolant pump switch within easy reach. I will probably mount this on the right side of the knee. 

My questions are:

1) Is this a quality VFD, and the correct one?
2) where do I get the other electrical components....pot, e-stop, forward-rev. buttons....etc?
3) How do I know which components are correct...voltage wise?

I am certain I will have more questions as this project progresses. 

Thanks in advance for the help!!


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## Rick_B

I did basically the same thing with a Bridgeport.  I have an Hitachi on a different machine and have had no problems with it.  On the bridgeport I simply wired the oem drum switch to the vfd low voltage controls  for forward, stop, reverse.  I also added a pot I got from radio shack.  I don't have an e-stop though.

Just another way to go

Rick


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## Pacer

This is my "bare bones" set up --- The VFD is wired off the oem switch and it stays on, the left toggle is just on/off 220v 20A that powers up the VFD, the center toggle is a common on/off/on that handles the low voltage for fwd/rev, and the pot is a radio shack special. they are stuffed in a radio shack box. Been up there for 5 years now and Ive never touched it since -- that Hitachi is good stuff.


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## Nightshift

melsdad said:


> Guys I am looking for some help to power my 2hp 3phase Kent KTM 380 mill. My electrical skills are limited but I can get help from a friend who is an electrician.
> 
> I am planning to use this VFD Hitachi WJ200 015SF Variable Frequency Drive 2 HP 230 Vac Single Phase Input | eBay
> 
> I would like run the VFD remotely. The drive will be mounted in a control box on the wall, with a small control box mounted on the mill that has a pot, e-stop, and forward and reverse buttons, and possibly a coolant pump switch within easy reach. I will probably mount this on the right side of the knee.
> 
> My questions are:
> 
> 1) Is this a quality VFD, and the correct one?
> 2) where do I get the other electrical components....pot, e-stop, forward-rev. buttons....etc?
> 3) How do I know which components are correct...voltage wise?
> 
> I am certain I will have more questions as this project progresses.
> 
> Thanks in advance for the help!!


That Hitachi VFD would work fine on my 2hp, 3-phase Bridgeport so if your motor is 8a or less, it will work great from single phase 240v power. All of my big equipment in the shop is either 3-phase or DC motors, with VFDs powering all the 3-phase. The VFD on my Bridgeport is mounting in a box on the backside of the pedestal where it's out of the way. I built a remote panel to bring all the controls up close with my DRO. I use nothing but Allen-Bradley 800 series components, but that's just my personal choice. Anybodys components can easily be used to control the VFD. My recommendation is to spend some time reading stuff on VFDs so you understand what you're doing because they all basically work the same way. The programming of each is just slightly different from one brand to another, so you'll want the manual for your particular VFD which will walk you through the programming options to operate it remotely. Bill


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## DMS

I have the same VFD, and am very happy with it, though I found the software configuration tool difficult to use (you can do everything through the display in any case). 
Here is a picture of my setup. My machine is CNC, so everything is controlled by the computer.


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## melsdad

Everyone thank you for the replys! The pictures are very helpful!

Nightshift....what brand of Tach is that on your control?


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## Nightshift

melsdad said:


> ...(snip)...Nightshift....what brand of Tach is that on your control?


It's called a Tachulator Module, made by Trexon.com in Toronto. You can buy them also from LittleMachineShop.com. About $100.

It works awesome with readouts for RPM and also SFPM if you enter the dia of the piece you're working on. Bill


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## melsdad

I am wondering if you have any trouble with the vfd interfering with your radio?

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## Nightshift

melsdad said:


> I am wondering if you have any trouble with the vfd interfering with your radio?


I've got at least 6 VFDs on various pieces of equipment in the shop and it has no effect on anything electronic in the shop ... radio, tv, wireless etc. Bill


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## melsdad

I guess that is something that may be shop specific. I have read about noise filters ahead of the vfd and wondered if I needed one while I was wiring everything. Guess I will just wait and see.

Thanks


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## Nightshift

melsdad said:


> I guess that is something that may be shop specific. I have read about noise filters ahead of the vfd and wondered if I needed one while I was wiring everything. Guess I will just wait and see.
> 
> Thanks



I should mention though that all my VFDs are mounted inside metal boxes. Maybe that makes a difference. Bill


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## astjp2

Get the largest VFD you can afford, I like to have a 3hp vfd for a 2hp motor, for service factor.  Tim


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## melsdad

Iam glad you mentioned that I am tossing around buying a 3hp drive

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## DMS

I had issues with noise, but that was hum from the motor itself. I adjusted the VFD frequency, and added a line reactor. Not sure which helped more. My line reactor is in the same box as the VFD.


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## WDG

I have three VFD's that I got off Ebay.  No problems with them.  One of the manufactures mentioned that even though you do not use it very often you should turn the power to the VFD on to keep the capacitors charged up.  Not sure what will happen.  The other thing to remember is to let the VFD start and stop the motor.  Do NOT put output power to the forward/reverse switch on the mill and use that to start stop and reverse.  The VFD won't like it and it probably won't last long.  Also I bought some pots and have some extra ones.  I bought several because the cost and shipping were better.  I can sell you just one if you want.  Let me know and I will send you a picture of it so you can see if it will work for you. warrengrant@yahoo.com  Put VFD in the subject line so I won't delete it.  One of the members mentioned that he used the drum switch and wired it to the VFD for forward and reverse.  That's a smart way to do it.  I put mine in a box and just turned the drum switch on and taped in that way so no one would move it.  Haven't had a problem.  I wired the VFD to two three phase outlets and unplug the mill when I want to use my surface grinder.  A little of a irritation but not worth buying a second VFD.


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## fitznoodle

Automationdirect.com has all the enclosures, push buttons, estops, etc you could want. No affiliation other than their name showing over and over again on my credit card statements. 

I also favor their vfds, btw. So easy to set up...


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## SEK_22Hornet

melsdad said:


> Guys I am looking for some help to power my 2hp 3phase Kent KTM 380 mill. My electrical skills are limited but I can get help from a friend who is an electrician.
> 
> 2) where do I get the other electrical components....pot, e-stop, forward-rev. buttons....etc?



I just did a search on ebay and found lots of Emergency Stop switches - this guy has the Estop and some other useful switches at pretty cheap prices.

http://www.ebay.com/itm/DC-AC-250V-...Domain_0&var=540186521659&hash=item4d0d50d6c1


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## melsdad

fitznoodle said:


> Automationdirect.com has all the enclosures, push buttons, estops, etc you could want. No affiliation other than their name showing over and over again on my credit card statements.
> 
> I also favor their vfds, btw. So easy to set up...



fitznoodle, or anyone else, are you familiar with this drive?

http://www.automationdirect.com/adc...ts_(115_-z-_230_-z-_460_-z-_575_VAC)/GS2-23P0

If I am reading the specs. correctly, it looks like the face plate of this drive can be mounted remotely and you would have all the controls you need...minus the E-stop, if that is really necessary. I can always mount the E-stop in the same remote box.


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## furpo

I'm using the Teco
http://dealerselectric.com/item.asp?PID=4710


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## fitznoodle

melsdad said:


> fitznoodle, or anyone else, are you familiar with this drive?
> 
> http://www.automationdirect.com/adc...ts_(115_-z-_230_-z-_460_-z-_575_VAC)/GS2-23P0
> 
> If I am reading the specs. correctly, it looks like the face plate of this drive can be mounted remotely and you would have all the controls you need...minus the E-stop, if that is really necessary. I can always mount the E-stop in the same remote box.



I have a GS2.  Yes you can pop out the HIM (human interface module aka the keypad) and mount it elsewhere.  But then you have to buy a patch cable and a thing for the keypad to sit in (cant remember the exact name for it).

Personally, when hands are dirty I find a keypad pretty crummy (and they get nasty looking in a hurry).  I use an RPC on my mill, so I just use the switch as it was intended, BUT if I was going to use a VFD as a phase converter, I would put an estop and pot in a smallish box somewhere close to the OEM switch.

Here is a 4 button box on my buffer (only 3 buttons being used + 1 plug).  These things cost so little I wouldn't think twice about it!

http://www.automationdirect.com/adc.../Pushbutton_for_22mm_-a-_30mm_(1_PB_to_25_PB)

Pots are not cheap from AD for some reason, if you can find one on ebay or somewhere thats prolly a good choice.


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## melsdad

Is this an appropriate pot for the drive I am after?

http://www.alliedelec.com/search/pr...&pmt=e&pdv=c&gclid=CL7Cu7fB4LoCFTBnOgodZHYASw


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## DMS

Did you decide on a drive? That is a 250k pot; my vfd recommends a 20k IIRC, it will vary by drive. The pot itself is nice, the conductive plastic ones are MUCH better than the cheaper carbon film type. The cheap ones work fine for a while, but are "scratchy" and soon you find your speed jumping all over the place every time you look at them funny. If you can tell us the drive you decided on, we can tell you if the size (ohms) is right.


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## melsdad

I decided on the Hitachi

   WJ200-022SF


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## SEK_22Hornet

melsdad said:


> Is this an appropriate pot for the drive I am after?
> 
> http://www.alliedelec.com/search/pr...&pmt=e&pdv=c&gclid=CL7Cu7fB4LoCFTBnOgodZHYASw



The critical values are the resistance value, given in Ohms , Kilohms (x100 and abbreviated K or K ohms), wattage, and taper.  The manual for the drive should give you these ratings.  The taper is the rate of change as the shaft is turned.  I'm thinking that the AB VFD I have calls for a 10K Log taper - the one you linked to is a 250K Linear taper.  So I'd double check the value and taper called for in the manual before ordering.  Good quality pots are pricey these days. The price given on that one is a good price for a name brand part. 

Dan


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## SEK_22Hornet

Found the Hitachi manual on line - the pot you need is a 1000 to 2000 ohm (1k to 2k ohm ) 2 watt pot.  Linear taper will work, however a log taper would give you expanded low speed control (the speed would change less at the low end of the pot's rotation, speed would increase faster at the high end, full clockwise rotation). I'll see if Allied shows the value you need and post a link later if they do. The info is on page 4-87 of the manual I found.

Dan


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## DMS

Dan beat me to it. The same part you linked to, but in a different size (2k instead of 250k) would be just the ticket.


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## SEK_22Hornet

SEK_22Hornet said:


> Found the Hitachi manual on line - the pot you need is a 1000 to 2000 ohm (1k to 2k ohm ) 2 watt pot.  Linear taper will work, however a log taper would give you expanded low speed control (the speed would change less at the low end of the pot's rotation, speed would increase faster at the high end, full clockwise rotation). I'll see if Allied shows the value you need and post a link later if they do. The info is on page 4-87 of the manual I found.
> 
> Dan



This pot should do the trick.  Same manufacturer and series, just the value that you need, according to what I found on line.

http://www.alliedelec.com/search/productdetail.aspx?SKU=70153148


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## melsdad

Thank You so much! This site is awesome!!


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## furpo

Oem drum switch to the vfd low voltage controls and radio shack pot


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## melsdad

Were do you guys buy your enclosures from? According to the Hitachi manual I need a minimum 9"w x 13"h x 7"d enclosure to house the drive.


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## Nightshift

melsdad said:


> Were do you guys buy your enclosures from? According to the Hitachi manual I need a minimum 9"w x 13"h x 7"d enclosure to house the drive.


I've bought them off eBay, CL and Kijiji. But mostly I get them (for scrap metal prices) from my local metal recycling/scrap yard. I drop in there every once in a while and wander around for a half hour. Almost always I'm able to pick up a few that aren't full of holes and sometimes they even come loaded with (expensive) Allen Bradley 800-series switches like e-stops, start buttons, selectors and pots. Bill


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## melsdad

I will have to try that. I will go to the yard where my machines came from


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## KenThacker

I just bought a new Baldor AC MICRO DRIVE VFD comes complete with FWD & REV and RPM knob"Brand New Model " Easy. Love it I mouted it next to my Off and On swithch, I used a small 1/4' x 2"X 12" alum plate as a bracket, used the same wire that came with the Mill. I just dropped out (1) wire from the cord for the single phase in and 

http://www.baldor.com/support/Literature/Load.ashx/BR760?LitNumber=BR760 

I got the one on pg 6 on the left. Its about 6 x 9 and light.

I called Baldor super easy 347.30 + 18 shipping= $365.30
[h=1]BALDOR Part Number VS1MX81-2D[/h]


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## melsdad

That bald or drive looks very nice! I already bought a Hitachi drive though. I will keep that in mind for the future. if there drives are as good as there motors they should be top notch!!


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## Harvey

Nightshift said:


> It's called a Tachulator Module, made by Trexon.com in Toronto. You can buy them also from LittleMachineShop.com. About $100.
> 
> It works awesome with readouts for RPM and also SFPM if you enter the dia of the piece you're working on. Bill



Nightshift,

I checked out the Tachulator.  Where and how did you mount the black/white encoder disk and the photo sensor?

Harvey


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## WDG

melsdad said:


> Were do you guys buy your enclosures from? According to the Hitachi manual I need a minimum 9"w x 13"h x 7"d enclosure to house the drive.



I used to be able to go to the scrap yard and pick up a ton of things for scrap prices.  They've since stopped letting people do that.  I now have to resort to the buddy system when I need something.  I tell all my friend that are in construction or demolition what I am looking for and they usually can find it.  Sometimes I have to wait awhile.  If I need something now, I go to an electrical supply house but you have to pay retail for it.  One of the most important things you can do locally is develop a network system with friends and don't forget CL.


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## Nightshift

Harvey said:


> Nightshift, I checked out the Tachulator.  Where and how did you mount the black/white encoder disk and the photo sensor? Harvey


Harvey, here's a few pics to show you how I did mine. The sensor on the Tachulator is has both a photocell to pick up the revolution marks as well as a LED to provide enough light so the sensor can differentiate between light and dark to send pulses. I removed the motor and top head cover to gain access inside to the variable pulley assy. I made a little aluminum block to mount the sensor near the front right corner inside the housing with the sensor level with the flat face on the lower half of the pulley assy. Then made up a small wire harness to connect to a Cat 5 receptacle which I mounted in the lower pulley housing (after making the appropriate hole for the connector to attach from the outside). A Cat 5 cable has more wires than the 4 you need, so even a 4-wire phone cord would work. I didn't use the sensor disc they provided. Instead I painted the flat face of the lower pulley flat black. Then hand painted every other section around the pulley face in white. If I recall, this gave me 6 white and 6 black sections. When I wired up the coiled Cat 5 cable to the Tachulator inside my control panel, the 2 wires for the sensor LED are powered thru the Power switch to the Tach & DRO, which in turn is powered by the master Power switch (that powers the VFD). I did it this way so when I turn off the master Power switch, it kills power not only to the VFD, but also the Tachulator and DRO which obviously don't need to be on when your not using the mill. Hopefully the pics help you. Cheers, Bill


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## Harvey

Thanks, Bill, the pictures will help my own installation a lot.

Harvey


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## melsdad

Next question..Resistance Braking. If I am reading the manual correct I need a 35 ohm resistor for the 2.2kw drive. My question is what is the correct wattage? IIRC I read , or someone mentioned to me 350- 500 watt.

We have a few machines here at work that have resistors from this place.

http://www.surplussales.com/Resistors/WireWound/WW30-499.html

We have one on a 1hp 3 ph hitachi drive but there is no wattage written on the part just the ohms.

I was looking at this model: (RWM) 26-136-35R   $25.00 seems like a good price to me.

- - - Updated - - -

Bill Thanks for the wiring pictures of the tach.! They are very helpful!!


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## melsdad

SEK_22Hornet said:


> This pot should do the trick.  Same manufacturer and series, just the value that you need, according to what I found on line.
> 
> http://www.alliedelec.com/search/productdetail.aspx?SKU=70153148



Will this pot have the low r.p.m. control you mentioned?

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## WDG

melsdad said:


> Next question..Resistance Braking. If I am reading the manual correct I need a 35 ohm resistor for the 2.2kw drive. My question is what is the correct wattage? IIRC I read , or someone mentioned to me 350- 500 watt.
> 
> We have a few machines here at work that have resistors from this place.
> 
> http://www.surplussales.com/Resistors/WireWound/WW30-499.html
> 
> We have one on a 1hp 3 ph hitachi drive but there is no wattage written on the part just the ohms.
> 
> I was looking at this model: (RWM) 26-136-35R   $25.00 seems like a good price to me.
> 
> - - - Updated - - -
> 
> Bill Thanks for the wiring pictures of the tach.! They are very helpful!!




I must be missing something.  Why do you need a braking resistor?  I have 3 VFD's and not one has a resistor.  You can control how fast you want the motor to wind down or speed up with the controller.  So why the resister?
Warren


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## fitznoodle

WDG said:


> I must be missing something.  Why do you need a braking resistor?  I have 3 VFD's and not one has a resistor.  You can control how fast you want the motor to wind down or speed up with the controller.  So why the resister?
> Warren



Depends on the rotating mass and how fast you want to stop it. I have 1 that doesn't need braking at all, 1 that does but I don't have a resistor so I set it to wind down longer and just wait, and 1 on a lathe that requires a resistor so I can stop a 10" chuck from 2000 rpm in 1.8 seconds. It all depends!


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## melsdad

I mainly want the resistor for tapping, and to take the wear off of the built in resistor in the drive.

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## melsdad

Night shift in post #4. The picture of your control panel. Is that the tachulator in the upper left corner? What is in the upper right corner?

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## Nightshift

melsdad said:


> Night shift in post #4. The picture of your control panel. Is that the tachulator in the upper left corner? What is in the upper right corner?


Hey Brian, yes the top left is the Tachulator. When I ordered it, I told them I did not want the alum box they provide with the face decal since I was installing in a control panel. They send me the stick on face panel so I could put it on once I cut the holes in the box.

On the top right is the remote display panel for the ABB VFD. Its connected to the VFD via a Cat 5 cable. The VFD is mounted in it's own box on the lower rear side of the pedistal to keep it out of the way. The remote panel allows me to change the program settings if I ever needed to (I haven't touched it since I initially installed it years ago). Bill


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## SEK_22Hornet

melsdad said:


> Will this pot have the low r.p.m. control you mentioned?
> 
> Sent from my SCH-I535 using Tapatalk



No - this one is a linear pot, meaning that the resistance (and resulting output voltage) should change about the same amount per degree of rotation across the entire rotation, so the speed rate of change should be pretty much the same at either end of the rotation.  I would start with a linear taper - if you want to make one end or the other less sensitive, it can be done by adding a fixed resistor from the center terminal to one end or the other.  If fact, you could add a three position switch and a single fixed resistor that would allow you have three different rates of change very easily with this same pot, if you wanted to.


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## SEK_22Hornet

Nightshift said:


> Hey Brian, yes the top left is the Tachulator. When I ordered it, I told them I did not want the alum box they provide with the face decal since I was installing in a control panel. They send me the stick on face panel so I could put it on once I cut the holes in the box.
> 
> On the top right is the remote display panel for the ABB VFD. Its connected to the VFD via a Cat 5 cable. The VFD is mounted in it's own box on the lower rear side of the pedistal to keep it out of the way. The remote panel allows me to change the program settings if I ever needed to (I haven't touched it since I initially installed it years ago). Bill



Great looking panel - Nice work!


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## melsdad

O.K. Bill here is another question. What type of transformer did you use to power your tachulator? How about one of these?

http://www.ebay.com/itm/AC-110V-220...ch-Power-Supply-Convert-Adapter-/400563914329

- - - Updated - - -



SEK_22Hornet said:


> No - this one is a linear pot, meaning that the resistance (and resulting output voltage) should change about the same amount per degree of rotation across the entire rotation, so the speed rate of change should be pretty much the same at either end of the rotation.  I would start with a linear taper - if you want to make one end or the other less sensitive, it can be done by adding a fixed resistor from the center terminal to one end or the other.  If fact, you could add a three position switch and a single fixed resistor that would allow you have three different rates of change very easily with this same pot, if you wanted to.




Dan this pot and resistor setup sounds great! Would you mind elaborating on the proper resistor needed, and how the wiring is configured?


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## Nightshift

melsdad said:


> O.K. Bill here is another question. What type of transformer did you use to power your tachulator? How about one of these?
> http://www.ebay.com/itm/AC-110V-220...ch-Power-Supply-Convert-Adapter-/400563914329


No ... way too big. I just used the little 9v-200ma wall wart that came with the tachulator. You can see it in the top right corner plugged into a 120v outlet box I put inside the panel. Bill


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## Harvey

Bill,

Nice work!  Are you a machinist or a machine maintenance technician?

Harvey
(A CNC tech many years ago.)


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## Nightshift

Harvey said:


> Bill,
> 
> Nice work!  Are you a machinist or a machine maintenance technician?
> 
> Harvey
> (A CNC tech many years ago.)


I've been retired for 7 years Harvey (freedom 55!). My training is engineering, but my career was management in a large fortune 100 company. Now that I'm retired, I spend a lot of time on the golf course. I consider myself a self-taught "hobby machinist" and have the luxury of a fully equipped machine shop that I play in when I'm not golfing. Mostly making or repairing parts for my hot rod buddies when we are restoring old muscle cars. Or refurbing old industrial machines. My most recent project was my '52 Monarch 10EE lathe. I love making parts on that thing! Like is good! Cheers, Bill


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## melsdad

Bill that picture of the inside of the panel is very helpful. Do you have a fuse block ahead of all the electronics for protection?

I was also thinking about adding a 220v to 110v transformer to power a coolant pump, and work light. Bill, Dan what are your thoughts on this idea? Is there another way?


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## Nightshift

melsdad said:


> Bill that picture of the inside of the panel is very helpful. Do you have a fuse block ahead of all the electronics for protection?
> 
> I was also thinking about adding a 220v to 110v transformer to power a coolant pump, and work light. Bill, Dan what are your thoughts on this idea? Is there another way?



Brian, the VFD is fused. Half of what's inside the control panel is low voltage signal wires to/from the VFD. I can't recall if the tachulator board had a replaceable fuse on it or not.

The other half is 120v wiring to power the receptacle inside the box (tachulator), the receptacle on the rear of the box (DRO, x-axis table motor, & z-axis knee motor), the hour meter (top left inside the box), chip vacuum, the 2 Dazor machine lights and all the pilot lights in the switches.

The main 240v power feed to the mill is routed first to the "Power" switch in the panel and from there feeds the VFD. So by breaking those two 120v input lines with that switch, it effectively kills all power to the VFD without fiddling around with multiple on/off switches.

You don't need a transformer to power your coolant pump. Your 240v input consists of two (2) 120v feeds. As long as you also bring a white "common" wire into your panel, you can power any 120v appliance with one of those 120v feeds + your common. Simple as that. Bill


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## melsdad

Awesome Bill! If I am ever in Canada I'll buy you a Molson!

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## SEK_22Hornet

melsdad said:


> O.K.
> 
> Dan this pot and resistor setup sounds great! Would you mind elaborating on the proper resistor needed, and how the wiring is configured?



Sure - here is what I'm talking about -


Does this make sense to you?  I didn't draw the switch I mentioned (too lazy to add it tonight), but I can add it if I need to later


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## melsdad

Sorry I didn't respond to your reply sooner. The drawing is very helpful!!

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## melsdad

Got another question. Where should I have the belt set on my step pulleys? I'm thinking the middle range. If this is correct should I be able to leave it there and forget about it? One reason I am asking is so I can determine a location for my tachulator sensor.

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## melsdad

Today I temporarily hooked up my VFD to the mill. Gladly everything seems to be in working order on the machine! I was going thru the settings and getting familiar with the drive. What I did find out is that I will more than likely need a breaking resistor to stop the machine. I kept changing the deceleration setting till the drive tripped and could not get below 4.75 seconds from 1100 r.p.m. I will still wait to buy one till I get the machine wired the way I want because it will be easy to add afterwards.


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## Muzzer

I'd leave the belt change system so you can swap belts over easily. It's true that a VFD allows you to cut down on belt changes but you shouldn't operate the motor for long periods under load at low speeds as it won't cool as effectively. Also, if you run at half speed, you are limited to half power. Similarly, if you run above base speed (whatever the rated speed is at 60Hz), you will not be able to develop full torque so power will be reduced there too. However, if you are doing low power work, it's handy to be able to vary the speed down to 20% or so (to use an edge finder for instance) and bang the speed up a bit higher for a small drill without changing belts.

I use my VFD to vary the speed all the time but I also change the belts and backgear to get the speed roughly where it should be. I wouldn't mind a Tachulator but for now I just set the closest speed on the lookup table with the belt and then change the VFD up or down slightly to get it more precise.

And BTW - check your VFD manual to see if it does "DC Current Injection". This is a form of braking that doesn't require the inertial energy to be dumped in an external resistor. Instead it generates a high braking torque in the motor by applying a stationary current to the windings. Don't worry - that's how induction motors work anyway. But normally when a VFD tries to slow down a motor it regenerates electrical energy into the VFD which then needs somewhere to put it. If there aren't enough losses going on in the VFD, it will either trip to protect itself or limit the ramp. DC injection may not get you quite the same deceleration as a large braking resistor but may still be a big improvement without the complication. And many VFDs don't have the option to add a braking resistor anyway. You can set the current at about the same as the current on the motor name plate.

Murray


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## WDG

Muzzer said:


> I'd leave the belt change system so you can swap belts over easily. It's true that a VFD allows you to cut down on belt changes but you shouldn't operate the motor for long periods under load at low speeds as it won't cool as effectively. Also, if you run at half speed, you are limited to half power. Similarly, if you run above base speed (whatever the rated speed is at 60Hz), you will not be able to develop full torque so power will be reduced there too. However, if you are doing low power work, it's handy to be able to vary the speed down to 20% or so (to use an edge finder for instance) and bang the speed up a bit higher for a small drill without changing belts.
> 
> I use my VFD to vary the speed all the time but I also change the belts and backgear to get the speed roughly where it should be. I wouldn't mind a Tachulator but for now I just set the closest speed on the lookup table with the belt and then change the VFD up or down slightly to get it more precise.
> 
> And BTW - check your VFD manual to see if it does "DC Current Injection". This is a form of braking that doesn't require the inertial energy to be dumped in an external resistor. Instead it generates a high braking torque in the motor by applying a stationary current to the windings. Don't worry - that's how induction motors work anyway. But normally when a VFD tries to slow down a motor it regenerates electrical energy into the VFD which then needs somewhere to put it. If there aren't enough losses going on in the VFD, it will either trip to protect itself or limit the ramp. DC injection may not get you quite the same deceleration as a large braking resistor but may still be a big improvement without the complication. And many VFDs don't have the option to add a braking resistor anyway. You can set the current at about the same as the current on the motor name plate.
> 
> Murray



I'm probably not doing it right but I set the VFD on my Mill at 60Hz and leave it there.  I vary the speed on the mill by turning the variable speed knob.  On my Bench mill I have put the belts on the slower speed and there by I run the VFD up the scale on Hz so I'm not dragging it down on low RPM.  As for the small lathe I have a pot and am changing speeds so often that I leave the belts on the middle pulleys.  My luck seems to be holding out as I've not had any problems. (yet)  Because of a recent turn in health problems, I'm not able to work in my shop as I would like to and may have to resort to selling my equipment off.


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## uncle harry

I'm a great fan of Automation Direct.  I have a GS-2 3HP on my BP clone mill with the removable control panel on the mill with F-OFF-REV &  E-stop mounted in a Home Depot plastic enclosure.  Their interface cable and another multiconductor cable make the connections to the drive in an enclosure mounted on the wall behind the mill.  Power is routed separately.  Another 3HP unit is awaiting installation on my Harrison M300 long bed lathe and a 120 VAC in 220 3 ph out unit awaits installation on my SP 9A. bench lathe.


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## melsdad

Bill, How do you like that joystick for control for your spindle direction? I have been thinking on going that route as well.


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## HMF

WDG said:


> I have three VFD's that I got off Ebay.  No problems with them.  One of the manufactures mentioned that even though you do not use it very often you should turn the power to the VFD on to keep the capacitors charged up.  Not sure what will happen.  The other thing to remember is to let the VFD start and stop the motor.  Do NOT put output power to the forward/reverse switch on the mill and use that to start stop and reverse.  The VFD won't like it and it probably won't last long.  Also I bought some pots and have some extra ones.  I bought several because the cost and shipping were better.  I can sell you just one if you want.  Let me know and I will send you a picture of it so you can see if it will work for you. warrengrant@yahoo.com  Put VFD in the subject line so I won't delete it.  One of the members mentioned that he used the drum switch and wired it to the VFD for forward and reverse.  That's a smart way to do it.  I put mine in a box and just turned the drum switch on and taped in that way so no one would move it.  Haven't had a problem.  I wired the VFD to two three phase outlets and unplug the mill when I want to use my surface grinder.  A little of a irritation but not worth buying a second VFD.




Check out WDG's article on putting a VFD on his mill! 
http://www.hobby-machinist.com/content.php/1353-Puttiing-VFD-on-my-Mill

Good work! I love to see how people do this!!


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## countryguy

Here is some info for a do / do-not I put into a thread last month.  
http://machinedesign.com/motorsdrives/feed-your-vfd-right-power


I recently hooked up to a BP 815 surface grinder to a China import 3HP for 135.  On my Mill, I did the Hitachi WJ300 line.  Both work well.   No pics of your junction box and contactor and such on your mill, but you will need to wire around or thru you old junction box setups.  VFD directly to Motor, fwd/rvs to VFD, etc.        For you Noise and chokes notes, the do/do-not has some good stuff.  Also there are some very nice VFD fused on/off input power throws.    automationdirect.com for a quick looksie and go from there. 

Ohhh.. And I bought my mill used. From a guy w/ an electrician buddy.   And the on/off for the Mill was a opn/close switch on 1 leg of the VFD 220 input.   don't let that happen to you.    




melsdad said:


> I guess that
> is something that may be shop specific. I have read about noise filters ahead of the vfd and wondered if I needed one while I was wiring everything. Guess I will just wait and see.
> 
> Thanks


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## melsdad

Realized I didn't show any finished picture of the machines control panel.


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## melsdad

Here is a closer look of the resistor cover


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## melsdad

I would also like to thank all of those that helped me on this project!  I honestly could not have tackled this project without the help from you guys.


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## HMF

Beautiful work!!


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## chips&more

SEK_22Hornet said:


> The critical values are the resistance value, given in Ohms , Kilohms (x100 and abbreviated K or K ohms), wattage, and taper. Dan




Sorry, but “K” is equivalent to three zeros. So, 1K is 1,000 and not 100.


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## WDG

I have three VFDs and only one is in a metal enclosure.  I don't pay much attention to the radio so I don't know if it would interfere or not.  I bought some extra pots but don't remember if they are 1 or 10 turn.  And I don't know if they would fit on your VFD if that's where your going to mount it.  Even if I put it in an envelop the cost would run about $10 shipping and for the pot so you can probably do better at Radio Shack as someone suggested.  I post some pictures that might give you an idea of what I did.  I had two different machines that I wanted to run off of one VFD so I had to wire it to a couple of receptacles and just remember not to plug two in at the same time.  Since I'm the only one using them it's not a problem.  On my lathe and bench mill I mounted the VFD on the mill from a plate and the lathe I just mounted it to the wall.  Plenty of smart people on the forum to help you out.  Most, smarter than me.


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## BeaverTec

Hello I see this is pretty old but I just bought the same mill and trying to hook up a VFD. Wondering if you had the wiring diagram or could point me in the right direction to where i could find it. Also wondering what the output voltage was on the VFD you purchased. I can’t tell what my Kent is wired for. Thanks for any help if you get this.


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## jmarkwolf

You'll want to confirm what the voltage requirement of the mill is. It may be 220-240VAC 3-phase, but could be higher like 480VAC 3-phase. Study the diagram typically mounted on the mill motor. If there are strapping (hookup) options on the diagram, inspect the actual wire hookups inside the wire box.

Then determine what voltage your shop can provide. The VFD can "bridge" this voltage by "making" the voltage that the mill requires from your available power when specified properly.

If you have 220-240VAC 1-phase available, purchase a VFD that matches your power with that needed by the mill. If you only have 120VAC available, there are VFD that will work but low end torque on the mill will likely suffer.

Purchase a VFD that has a manual written in good english, otherwise it will be a PITA to understand.

Become familiar with operating the mill from the VFD front panel before attempting to wire up a remote control box.

Be advised do not connect any switches between the VFD and the motor. This will kill a VFD. All such switches and controls will have dedicated connections on the VFD.

Do a search on YouTube and you will find numerous video examples on how to do this. Watch many to get the gist of it, not just one.

Let us know of your progress on a new thread. This thread is going on nearly a decade old!


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