Help requested wiring VFD – Again!

[John HinkleyParticipant @johnhinkley26699]

[John HinkleyParticipant @johnhinkley26699]

As documented elsewhere on the site, I've been working my way round the workshop converting my machines to 3-phase motors with VFDs one per machine. I started with the mill with a HuangYang VFD. Easy, peasy. Then the shaper with a a cheap import controlled from the panel – no problem.

Now the lathe. Again a cheap import supplemented with a forward/reverse switch, E-Stop switch and Speed pot in a remote unit bought from the Internet. I thought it would be simply a matter of following the same steps as with the mill (also has remote), but oh no! I can get the forward/reverse switch to work despite an incorrect wiring diagram supplied with the remote. Can I get the VFD to recognise the remote potentiometer? Well, no, actually, I can't. These are the connections additional to the mains in/3-phase out in the manual:

My dilemma is where to connect the pot leads? The obvious connections are GND and 5V out to either end of the pot track and pot wiper to the 5V in terminal. Combine that set up with parameter changes Pn04 to 2 (External signal control) If I set Pn03 to 1 (Pot frequency control) it runs but no speed control. Set Pn03 to 3 (External 0-5V) the lathe doesn't run at all and the pot doesn't alter the displayed frequency.

Any bright ideas, chaps? I've been pulling my hair out over this for two days, off and on and I'm reluctantly resigning myself to operating the lathe from the onboard panel for the time being, or buying another HuangYang unit.

John

Hope the manual scan is legible.

[SillyOldDufferModerator @sillyoldduffer]

Have you tried Pn04=1 (Command from panel), and Pn03=1? Then press run, and twiddle the pot. Should prove the VFD is working.

I think you have the pot wired correctly (though what value is it?) but it's not clear where the external start input is. Just a guess, but it may be done by putting +5 on either FWD or REV. ie they are Run FWD and Run REV, rather than just direction options.

Dave

[Michael BriggsParticipant @michaelbriggs82422]

Hello John, is Pn03 = 1, frequency reference from the pot on the front of the drive. Have you checked to see if there is a voltage present on the 5V IN terminal when you are trying Pn03 = 3 ?

Regards,

Michael

Edit – The digital inputs are switched to COM to energise them as you have seen on YouTube.

Edited By Michael Briggs on 25/09/2020 19:30:53

[John HinkleyParticipant @johnhinkley26699]

Dave,

I'll have a closer look at your suggestion and maybe try it out tomorrow. I've received a PM with some other suggestions, too, so more food for thought. To be honest, I've tried so many wiring/parameter combinations that my brain is a bit addled. I have found, however, from watching a youtube video, that to remotely switch between forward and reverse, there has to be a connection from COM (ground) to the respective FOR or REV terminals – but not at the same time, of course!

John

[John HinkleyParticipant @johnhinkley26699]

Michael,

I haven't tried that yet. My vfd is the type that has up and down buttons for frequency control, not a potentiometer. It's a cheap unit! I'm beginning to regret being tight-fisted, but I thought that it would be as easy to connect up as the HuangYang one.

John

[John HinkleyParticipant @johnhinkley26699]

Double post removed!

 

Edited By John Hinkley on 25/09/2020 19:27:38

[David JuppParticipant @davidjupp51506]

It looks like the VFD can read either a current or voltage input to control speed. You'll have to tell it which to use – presumably a parameter setting.

 

EDIT – looking again, that's a matter of wiring to the correct terminal and setting the parameter.

Edited By David Jupp on 25/09/2020 19:46:03

Edited By David Jupp on 25/09/2020 19:47:34

[Michael BriggsParticipant @michaelbriggs82422]

John, in which case Pn03 = 1 may be invalid for your drive. I have been looking at a manual for a drive (on the web) that has a small knob (potentiometer) on the front, pages 11 and 12 of that manual are exactly the same as pages 11 and 12 in your manual.

Michael

Edited By Michael Briggs on 25/09/2020 20:09:54

[John HinkleyParticipant @johnhinkley26699]

David,

Yes, I'm using (or at least trying to) voltage variation to adjust the speed.

Michael,

That isprobably explained by the fact that my manual cover two different VFDs- one with and one without a panel mounted potentiometer. Which only serves to confuse matters even more. I'll get there-maybe not tomorrow, maybe not the day after, but sometime. I won't be beaten. Think I'll check out the internal fuses, just in case. The manufacturer thoughtfully suoolied three spare ones inside the terminal cover. They must have know I might do something stupid!

John

[peak4Participant @peak4]

FYI, The manual seems to be HERE which has a wiring diagram
http://www.et.byu.edu/~sorensen/A2%20VFD%20Manual.pdf

Haven't got time to look into it further at the moment

Bill

[John HinkleyParticipant @johnhinkley26699]

Bill,

Yes, that's the same manual as the one that came with the vfd, same manufacturer. My problem is getting my head around the parameters and my fingers around the wiring. I'll go back to square one parameter-wise and start again this morning. At least I can make it run forwards and backwards.

John

[John HinkleyParticipant @johnhinkley26699]

Well, with a combination of help from here, a deep re-think, a reset to factory settings and a night's sleep later and it's sorted. Everything is back together and working as it should. Except I have mislaid the 4mm key that drives the spindle gear. It would be the smallest one, too. I'll have to wait until Monday when the key steel I've ordered arrives before I can do any cutting under power. Manual feed only for the moment.

A big thank you to everyone who responded either on here or by PM for your help.

For the benefit of anyone following in these tracks, these are the settings I used with reference to the manual page 9 in Peak4's post:

Pn01 = 1 Displays instantaneous frequency

Pn02 = 50 Starting (base) frequency

Pn03 = 3 Selects remote pot wiper as source for frequency control

Pn04 = 2 Selects remote forward/remote switch for direction selection

Pn07 = 2 Enables the start again function from external source

Pn08 = 2.5 Seconds My choice of acceleration to speed – I always reduce to zero speed on the pot before switching off.

Pn09 = 2.5 Seconds. Deceleration time see previous note

Pn10 = 60Hz Maximum frequency set in the software.. Again, my personal choice to prevent chuck overspeed in highest gear ratio.

Pn12 = 50Hz. Motor rating frequency

The rest are as per the manual.

Remote wiring connections reference page 5 of the manual referred to above:

Potentiometer: "low" side – to GND, "high" side to 5V OUT, Wiper to 5V IN

Forward/Reverse switch: GND to one side of the switch, the relevant lead to the respective FOR and REV terminals on the VFD.

Hope that helps someone.

John

[Peter SansomParticipant @petersansom44767]

I bought a VFD several weeks ago from the local branch of the well known auction house. Turned out to be the A2 VFD when it arrived. Post is very slow here at the moment.

My question is, what is the value of the external potentiometer.I find the value hard to read in the manual, is ,1 1.5k ohm or 1-5k ohm. What value are you using?

Thanks

Peter

[not done it yetParticipant @notdoneityet]

Most VFD manuals are on the internet. Have you searched for yours?

[Peter SansomParticipant @petersansom44767]

Yes, I have the manual, just poor printing and my eyesight and poor printing of the manual.

Peter

[SillyOldDufferModerator @sillyoldduffer]

Posted by Peter Sansom on 07/10/2020 08:10:15:

…what is the value of the external potentiometer.I find the value hard to read in the manual, is ,1 1.5k ohm or 1-5k ohm.

…

The value isn't critical; 1 – 5k ohm most likely means any pot between 1.0k and 5k will do. I'd go with 4k7 linear, such as this example from Farnell. Plenty of other suppliers available.

Dave

[not done it yetParticipant @notdoneityet]

If you supply the url for the pertinent manual, perhaps our eyesight might be able to read it for you?

[Peter SansomParticipant @petersansom44767]

Thanks Dave, I am just looking at the parts for the pendant control and need to purchase a 3 phase motor.

Peter

[John HinkleyParticipant @johnhinkley26699]

Sorry to jump back in, just seen this crop up. I think, to be pedantic, the pot needs to be 0 to 5K Ohms, at least, that's what mine is. It works fine but I also believe that the actual value (up to 10K Ohms) is not super-critical. 5K in my case seems to give a reasonable 'feel' to the control over the full range of frequencies.

John

[SillyOldDufferModerator @sillyoldduffer]

Posted by John Hinkley on 07/10/2020 10:00:22:

Sorry to jump back in, just seen this crop up. I think, to be pedantic, the pot needs to be 0 to 5K Ohms, at least, that's what mine is. It works fine but I also believe that the actual value (up to 10K Ohms) is not super-critical. 5K in my case seems to give a reasonable 'feel' to the control over the full range of frequencies.

John

Well the pot is used as a potential divider allowing the user to put between 5V max and 0V on to the controller input. Basic stuff, not fussy, where 300 ohms is nothing between friends.

First consideration is how much current the pot consumes whilst dividing; too low a value and the pot will burn out or overload the 5V source. At 5V, a 1k pot draws only 5mA, which is 24mW. The Farnell sized pot I linked is good for 400mW. Next physical size down are about 200mW so they're fine too. Pretty safe for pot and supply. At 5V, a 5k pot draws 1mA, which is a massive safety factor.

Second consideration is how much current the controller input draws. We don't know. If it draws significant current then a high ohm pot might not be able to source it, causing non-linear speed control, maybe unable to reach max speed. Although it depends on the design controller inputs are unlikely to require significant current; microamps rather than milliamps. It's low risk.

In practice any pot between 1k and 22k should work: a value like 4.7k or 5k is a reasonable compromise.

My comments only apply to controller inputs and similar: other electronic circuits are critical.

Dave

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