How hard is putting a VFD on a 3phase 1440 GT ?

On page 2 of my PM-1440GT thread I show what I did for my VFD conversion. Really not that hard using mksj's schematics as a guide.

 
I have also done the VFD install on a mill and lathe without too much previous experience, not easy but not difficult either. (with help from Mark Jacobs)

RPC's Rotary Phase Converter, converts single phase to 3 phase, normally used for higher HP machines or multiple machine off one device.

VFD's are perfect for this application.,

Contactors are the electrical switches that come with the lathe, they are not needed as you are no longer switching high voltage, but can be repurposed in the basic conversion if they are new.

The other option which is what I did was to buy new 24VDC relays and installed all new parts, added a few $$ but I wanted some of the extra options so went that route.

Good luck


David.
 
Terminology is Rotary Phase Converter commonly used to turn single phase into 3 phase by essentially generating the 3rd phase through another motor and using capacitors to to phase/balance the voltage of the generated leg. It is probably the simplest approach if you do not need the additional features of the VFD.

As far as removing the control board that is your choice as to removing it or not, some people find it easier with it out. The wires are labeled as to the connections. The posted basic VFD install for the VFDis straight forward as to the pictures and detail, but if you do not have the machine in front of you it is a bit more difficult to follow. Anyway you go you will have some wiring to do unless you decide to go with the single phase 1440GT.

A brake resistor connects to the terminals on the VFD and has wires to the brake resistor which helps dissipate the excess voltage generated when braking. It is usually mounted against a flat metal surface near the VFD.

The tach. is not outputted from the VFD because it needs to read the spindle RPM not the motor, so you can buy an inexpensive tach. that uses a hall sensor and a magnet. It is a stand alone unit, I usually mount it under the DRO and also put the speed pot in the same enclosure.

You only use the inputs you need on the VFD, they can be programmed to do many functions. Typically on the basic install you want forward, reverse, jog and probably single stage or 2 stage braking (there are two sets of programming parameters for acceleration times and deceleration times.

There are many different ways to wire in the VFD, some better than others. But it is not a simple matter of connecting single phase into the VFD and connecting it directly to the machine. Machinery/the lathe can be very dangerous if you do not have the proper safety and redundancy to prevent the machine from running unintentionally.

As mentioned, single phase version the the lathe is also an option.

288321
288322
 
Wow thanks Mark. (Sorry I called you Mike)...

I’m getting a 3 phase because they are less likely to chatter / vibrate or are smooth.

Looks like I’m off to buy some brake resistors and a tach (I like that).
The lathe I’m getting will have the Easson DRO on it so it’s going to look a lot like that pic. :)

I won’t have the lathe in front of me for a while, but I’ll download the doc’s from MKSJ’s thread...
My plan is to pull off the old board wires replacing them with the new wiring until none are left... if and when that happens I’ll pull the old control board. :)
 
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On page 2 of my PM-1440GT thread I show what I did for my VFD conversion. Really not that hard using mksj's schematics as a guide.


Jay - really nice work !!

As I’m reading Marks and your work -

- it looks like you replaced the old controls with low voltage options ?
 
Jay - really nice work !!

As I’m reading Marks and your work -

- it looks like you replaced the old controls with low voltage options ?
The only original electronics I kept was the 5v/24v/110v power supply and the fwd/rev switch that sits at the end of the bed. Everything else was replaced. The forward and reverse commands to the VFD are through 24v relays. I have contactors with 110v coils for the main power and coolant pump. I kept the manual brake and have the VFD programmed to freewheel when the foot brake is used otherwise under normal use without the foot brake the VFD does electronic braking. I have braking time set to a few seconds. I occasionally get VFD faults with electronic braking from speeds over 1200 rpms and a heavy chuck. I'm sure that could be tuned out.
 
Will the kbac 27d work? i used one for my grinder as it was nema 4x and didnt have to worry about dust and water. Sorry for thread stealing
 
I'll be the one who goes against a tribal norm, so I'm just going to selectively paste from something much more in depth I wrote in another setting. Executive summary... if don't design electrical products all day every day, and if you value your ass, don't start on this.

Pasting..

Reluctant to post this... I like my anonymity but I will offer I am "qualified" to comment on how electrons move in a conductor.. what ground/bonding ACTUALLY is... and how to diagnose/isolate nontrivial electrical problems which I will add I spent almost 4 decades doing for others. Further, the entire back half of my career was finding crappy technical decisions made by guys who design all day every day which fail in ways even these educated practitioners either could not imagine or more commonly, because they just phoned in some important decision (a design is just a huge collection of interrelated technical decisions. So.. let me put something out there just once.

Tribal knowledge about lots of things is great. Tribal knowledge about mechanical and in particular electrical/electronic things can be insanely poor... and is insanely wrong in the expected case. Since the beginning of 2017, I have had 9 people [up to 13 as I paste this]... not crack addicts... not pill heads.. people successful in life most who know me and what I did for decades LECTURE me on how electricity works and why I just had to be 180-degrees wrong about something which, in all 9 cases, they asked for my opinion. None had ANY actual training in anything electrical. None were practitioners of anything that involved electricity, or had any saddle time as actual designers. Their 0 hours to my multiple 10's of thousands of hours. All were armed with "tribal knowledge" (e.g. forums and email lists). Nice guys... and also idiots... as most humans become post-financial success (look up the OK Plateau). All could be characterized "Google smart" (i.e. unskilled and unaware). Do NOT bet your ass on something you read online. Do NOT make it more wrong and more deeply held by parroting it for tribal participation points. Make your default assumption for how someone tells you (insistently.. authoritatively) how to deal with something electrical to be "idiot". There is zero up-side to any other strategy. No LIKE buttons down at the morgue.

...

I'm starting to shotgun here... let me try to stick to the point.. tribal electrical "knowledge". It is massively likely you don't have the ACTUAL big picture in mind when you contemplate electrical or decide something you read from someone you don't know "sounds good". You aren't qualified to say so is a stochastically true statement. So please do yourself and your friends and the guy on the next boat (next owner of your machine tool) a huge favor and leave it alone. There are more things in heaven and earth... AND... the human mind has some really serious mechanisms hard wired right in to the standard-issue human mind to drag you off the path to the right answer. Not trying to pick on people... just our species. The human mind is not a mysterious thing.. stupidly predictable. It's your ass... for the same reason you aren't going to jump in and take a swing at spinal chord surgery on your spouse, don't think the world of correct and (and MORE CRITICALLY) failing electrical system behavior is accessible to you if you don't do it all day/every day. The failures are stochastic.. you aren't guaranteed to kill someone. Just more likely. You create the vulnerability and that is compounded by the fact you have no idea what the set of vulnerabilities even are.

Gaussians are scary real. Rigor lives WAY over in the thin tails on the right side. The value of rigor is that it defends YOUR ASS from things you very likely aren't aware of or have the neural connections to even imagine. If you don't design (things that affect other people) everyday... don't design such things on ANY day. And "affect" = not just during routine operation but in the presence of less common environmental and component and operational issues.


End paste...

Pick anything... all Porche forum members "can drive". All Harley forum members are God's gift to riding. Every soccer mom is a brilliant solutions designer particularly in those areas where their solution design strategy is uncontaminated by training/experience (Mothers Against 3-Digiti IQ's)... Just invoke the ridiculous concept of "common sense" (sense without actual skilled thought) and count on tribal politeness to coast unhindered from there. Doing something because everyone else in the virtual club house does it is ENTICING. That's in large measure how all this tribal stuff works. It's awesome in that it gets you moving forward on things you might not otherwise do.... But that doesn't always work... not all domains should be screwed with by rookies and again... design is a skill set to begin with.. You aren't GUARANTEED to kill yourself or your family or a visitor to your shop of those around the next owner. You want to take a swing and improving your surface finish with a new tool grind? Swing away. You want to DESIGN and build something that affects others who didn't sign up for the risk you are creating? Please do not.

The hard part isn't feature implementation but that's THE thing on which every rookie seems to enter. No thoughts around the second and third order design considerations that drive operator and machine safety. With a much deeper than average electrical/electronic design background, I spent 3 months doing mine, though I have learned not to expect most would be willing to build something they would have been willing to sign off on to release to market (other than one single component I regret including). Take away all the "design elegance" stuff and the safety stuff at both the system architecture and implementation levels still was good for 2 months. I've seen a lot of designs on line and all I ever seem to notice is feature-centric decision-making.

I don't like pouring cold water on enthusiasm. Generally. And doing it for free.. vastly less so. I prefer infinitely to learn interesting new things rather than to teach/advise. But bad technical deciding in the face of small high-consequence opaque risk (my field) abound.. are the norm... and unfortunately I've already harmed one good guy in my world by being politely quiet at the wrong time. Buy off the rack those things you can't afford to screw up.

Capt. Wet Blanket
 
Clock work, you may have a good point, perhaps you would identify the specific safety issue(s) you are concerned about?
 
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