# Kent (BP Clone) on VFD



## Mr. Kelly (Oct 26, 2012)

I successfully turned a 10 hour job into about 40, but I'm really happy with the results.  I got myself a Chinese 3HP Variable Frequency Drive for cheap.  At the price I paid, I figured it was a worthwhile experiment.  The plan was to use it instead of sharing the RPC with the compressor that it's currently powering.  
As the VFD only powers the (spindle) motor, I had to figure out a way to power the coolant pump and run the table feed.  To do that required fully rewiring the electrical of the mill.  Here's a quick video of how it turned out. 

 [video=youtube;mKDn6rF6CKI]http://www.youtube.com/watch?v=mKDn6rF6CKI&amp;feature=plcp[/video]

I've got one problem that I can't figure out though.  I used the correct pot and I've got the VFD programed to vary speed based on a 0-10VDC range.  I've confirmed that I've got that spread out over the full range of the pot.  However when running, the VFD reaches max programmed speed at 25% travel of the pot travel.  By using the 5VDC output, I get full rpm at 50% on the dial (which is what you see on the video).  I can't figure out why it's doing that.  Anyone have any suggestions?

-kelly


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## Pacer (Oct 26, 2012)

Interesting ... Thats a 'Huangyang' VFD? right? 

I recently got a 2hp one for the amazing price of $120 delivered! Like you I figured I couldnt go to far wrong with it and decided to give one a try. I did research them quite a bit and most of the reviews were concerning use with CNC applications - and, since other than getting 3ph, I was only going to take advantage of the variable speed and ramp/ramp down time settings, it should be fine for my use on my lathe. Other than a bit of head scratching figuring the parameter settings, it performs very well. I have 2 other Hitachi VFDs and programming is a good bit different.

Well, I do have _one_ minor oddity and its the same one you have - the potentiometer, except mine is the reverse of yours, and the pot will only start to engage at, or past, the center point, with full rpms achieved at full turn. I didnt pursue it much (at that point I was frustrated with fooling with the parameter settings!) and having used it some now, I find its only a minor irritation and probably wont try to correct it. I used an unknown pot from my junk drawer, and wonder if maybe it may be was the cause??

As for the wiring, I discovered on my 2nd or 3rd install of a VFD, that all I needed was 2 common toggle switches and the pot to get up and running. A 220v/20amp dpdt toggle to power on/offthe VFD, and a simple on/off/on common toggle to control the fwd/off/rev of the 24v cnx.
Ive got a lathe and a mill (bridgy clone) been running on this type set-up for several years now. I just ran my 3 power feeds/DROs/lamps to a wall 110v socket.


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## Mr. Kelly (Oct 27, 2012)

Pacer said:


> Interesting ... Thats a 'Huangyang' VFD? right?
> 
> I recently got a 2hp one for the amazing price of $120 delivered! Like you I figured I couldnt go to far wrong with it and decided to give one a try. I did research them quite a bit and most of the reviews were concerning use with CNC applications - and, since other than getting 3ph, I was only going to take advantage of the variable speed and ramp/ramp down time settings, it should be fine for my use on my lathe. Other than a bit of head scratching figuring the parameter settings, it performs very well. I have 2 other Hitachi VFDs and programming is a good bit different.
> 
> ...



Yah, it's Huangyang, a (relatively) super cheap experiment.  I'm not expecting high quality and I understand you get what you pay for.  I think I have proof of concept now, so if this one dies, I'll be willing to spend the bucks on a higher quality.  Might even buy in advance if I find a cheap deal on eBay.  
The manual was OK, there were some obvious blatant errors in it that weren't hard to figure out.  Programming parameters was reasonable for me after going through the manual a few times back and forth.  Once I had decided how I wanted it to work, it wasn't hard to program it to do what I wanted.
I'm glad to hear that you've got problems with your speed control as well.  I was worried that maybe I had hooked something up wrong, but maybe it's a design flaw of the internals.  
With yours, I'm wondering if you have the '10V' and 'ACM' legs reversed on your pot, maybe that's why it's in reverse?  But I would think that you would then start at full RPM at your center and _decrease _down to zero then.  Maybe the wiper is reversed with one of those legs.

For the switching I decided to use the contactors for a couple reasons, mostly because they were there.  The main contactor gives me the safety factor so that if I get some flickering power, I'm isolated after the first loss of voltage.  I'm running both legs of the 220 through it, as well as the hot leg of the 110V which runs the table and coolant.  If I get bad power, it isolates everything until I reset.
I used a contactor for the main spindle which both signals the low voltage to the VFD to run, and also the controls the 110V feed to the table controls.  That way the stop switch kills both the table feed and the spindle.  I did this so that if I had to E-stop the spindle, the table did not continue to feed the workpiece into stopped tooling.
The third contactor triggers the coolant pump (once I get it hooked up).  I could have just used the switch directly, but this allowed me to use the lighter gauge shielded wire, and like I said, it was there so I used it. 

I'm going to play around with some resistors and see if I can get the full range of the pot so it's not so sensitive, but not right now.  I've got some work to do with it. 

-kelly


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## strantor (Oct 29, 2012)

Mr. Kelly said:


> I've got one problem that I can't figure out though.  I used the correct pot and I've got the VFD programed to vary speed based on a 0-10VDC range.  I've confirmed that I've got that spread out over the full range of the pot.  However when running, the VFD reaches max programmed speed at 25% travel of the pot travel.  By using the 5VDC output, I get full rpm at 50% on the dial (which is what you see on the video).  I can't figure out why it's doing that.  Anyone have any suggestions?
> 
> -kelly



I'm not sure why, but I suspect it's something in the programming. In any case, you can work around this by installing a trim pot in the cabinet. 

This thread is old so I figure you probably got it fixed. If that's not the case, let me know, and I will provide more details if needed.


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## Mr. Kelly (Oct 30, 2012)

No sir, not fixed yet.  I double checked and I reach max programmed frequency at something like 2.1 volts.  I've double checked settings in the programming and can't see anything to change that would help.
I was thinking exactly the same thing about throwing a trim pot in there to stretch out the range of the main control pot.  Haven't had a chance to play with it yet, so if you've got some suggestions, I'd appreciate it.
Thanks!

-kelly


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## strantor (Oct 30, 2012)

Mr. Kelly said:


> No sir, not fixed yet.  I double checked and I reach max programmed frequency at something like 2.1 volts.  I've double checked settings in the programming and can't see anything to change that would help.
> I was thinking exactly the same thing about throwing a trim pot in there to stretch out the range of the main control pot.  Haven't had a chance to play with it yet, so if you've got some suggestions, I'd appreciate it.
> Thanks!
> 
> -kelly



Not being present to lay hands on it, my shotgun answer is the trim pot. Usually you only use 2legs of a trim pot, but to overcome this extreme trim, you'll need to use all 3. Disconnect the speed pot from +10v and Connect the trim pot just like you have your speed pot connected now (minus the wiper ... there should be 2 pots connected to gnd) then connect the wiper of your trim pot to the side of the speed pot that used to be connected to +10v. Adjust to trim pot so it feeds 2.1v into the speed pot. Now your speed pot will vary the voltage 0 to 2.1v. If that's not clear, I can draw it Up tomorrow.


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## Mr. Kelly (Oct 31, 2012)

I was almost thinking the same thing.  I was thinking the 2 legs, but I think what you've described here is what I _should _be doing.  
I won't have time to get to it until the weekend, but I'll let you know how it turns out.

Sounds like a simple fix. 
Thanks!

-kelly


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## Tony Wells (Oct 31, 2012)

Put a ten turn precision pot in place of the original. Fine tuning, plenty of range.


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## Mr. Kelly (Nov 1, 2012)

Tony Wells said:


> Put a ten turn precision pot in place of the original. Fine tuning, plenty of range.



That had crossed my mind when I was originally planning the setup, but decided to go with a single turn so that I could label the panel.  I was hoping to print speeds at 1/4, 1/2, 3/4, 4/4 for each belt range, but it would be too small to read.  At the very least I'd like 1-10 on the dial, so a multi turn would make that difficult if not impossible.  
I hadn't planned on a remote frequency readout, hence the need for a numbered dial, but I'm re-thinking that.  The VFD has an output that will put out 1-10 volts based on the percentage of full RPMs, so I could probably hook a small voltmeter to it which would read in 10s of percent.
That is of course, if it's actually putting out the 1-10v as the manual states it should.  I haven't verified that yet.

-kelly


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## strantor (Nov 5, 2012)

CluelessNewB said:


> Another thing to consider is the type of pot you are using. They come in two basic flavors "Linear" taper and "Audio or Logarithmic" taper. For this application you would want a "Linear" taper. Most of the pots you find at places like Radio Shack are "Audio" taper.
> 
> You can read about the 2 types of pots here:
> http://en.wikipedia.org/wiki/Potentiometer


That's a good point, but I don't think it's the issue at hand. see below:


Mr. Kelly said:


> I reach max programmed frequency at something like 2.1 volts


Even if he had an audio pot in there, the pot *should* still divide the voltage between 0-10V and drive *should* still respond to that. It would just be less responsive at one end of pot travel, and overly responsive at the other end.


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## Mr. Kelly (Nov 6, 2012)

Hi All,

Had a bit of time this weekend to work on the mill and get the last couple things finished up.  I installed the second pot as a trim pot as suggested and got it dialed in to work perfectly.  Full range of speed over the travel of the dial.  

I also was able to get the single phase coolant pump all hooked up.  It was a little too large for the bracket and had me scratching my head for a few minutes before I remembered that I had a milling machine and a boring head.  Duh!  Sure felt like an idiot for a few minutes.:whistle:  My first real work on the mill got the bracket bored out the 20 tho more that it needed to clear the new pump.  
I needed to mount the boring bar in one of the horizontal holes to get a large enough diameter, but of course an RH cuts LH when mounted horizontally.  No problem with the switch I wired in for direction.  Flip the switch and bore in reverse.  Too easy!  Glad I decided to put that one in there.

I ordered a cheap eBay volt meter which I'm going to use for a remote display for percentage of full RPM.  I think I'm going to mount it on the new DRO that's sitting down at the post office waiting for me to pick up!!  _It's like Christmas, I'm so excited!  _I guess I know what I'm doing this weekend!

Thanks again for the input and help.  I'll post up another vid once I get the DRO installed.

-kelly


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