# Which VFD should I get for my PM-835S?



## Pcmaker (Mar 13, 2021)

I am thinking of buying a 3 phase motor for my PM-835S from Precision Matthews so I can have variable speed without having to keep changing belts on the step pulley. I need a 220v 1 phase input, 220v 3 phase output VFD, something that can reverse directions.

Any recommendations or is that something I should also talk to PM about and order it from them also?


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## JimDawson (Mar 13, 2021)

Any properly rated VFD will work.  Look for one with Sensorless Vector control, slightly more expensive but worth every penny.  Gives you more low speed torque.  Sensorless Vector control could be called something else depending on the whims of the marketing department.  If you have a question about it, check back here and someone will help you wade through the specs.

Don't buy the cheapest VFD on Ebay or Amazon.  Teco, Automation Direct, and Lenze are good brands.  There are others also.


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## Pcmaker (Mar 13, 2021)

I'm leaning towards something with a control knob instead of buttons for speed control also

Something simple like this, but for a 3 HP motor


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## pacifica (Mar 13, 2021)

Just be sure that whatever you get it is relatively easy to program the parameters and  with the proper documentation.
There are quite a few threads here on parameters most useful to home shops, since there are virtually 100's of different parameters with many only used by industrial shops. That's one reason for buying a known brand.


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## JimDawson (Mar 13, 2021)

The 3hp unit at $360 seems a bit pricey.  I think this would be a better value, and more control.  https://www.automationdirect.com/ad...quency_drives_(vfd)/general_purpose/gs21-23p0


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## mksj (Mar 13, 2021)

The usual VFD that I see people use on this type of mill is the Teco L510 series. If you are looking at the KB series I would go with the KBDF-29 which is there newer series which is also suppose to be GFCI compatible. I have used the KBMA VFD, had it on my mill for one of the drives and it was unimpressive. The easiest way to control the VFD is to strip out the high voltage to the FOR STOP REV switch and just use input 1 and input 2 on the VFD for forward and reverse.  You also want to program it to not start if either input is active when it is powered up. Alternative which is also very simple is 3 wire control, momentary stop and start buttons and a sustained reverse switch. All VFD's are going to need some basic programming to get them to perform correctly and set the motor characteristics. I believe the Teco also has a removable control panel and one can get a cable extension so it could be mounted on the head.





						Teco-Westinghouse, L510-203-H1-U, 3 HP, Variable Frequency Drive 230 Volt, 1 Phase Input, IP20,  at Dealers Industrial
					

Purchase Teco-Westinghouse, L510-203-H1-U, 3 HP, Variable Frequency Drive 230 Volt, 1 Phase Input, IP20,  from Dealers Industrial, formerly L510-203-H1-N




					dealerselectric.com
				











						KB Electronics, 9641, KBDF-29, 2;3HP, 1;3-Phase, 200-240V (Input), IP 20 Enclosure, Variable Frequency Drives
					

KB Electronics, 9641, KBDF-29, 2;3HP, 1;3-Phase, 200-240V (Input), IP 20 Enclosure, Variable Frequency Drives




					motorsandcontrol.com


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## Pcmaker (Mar 15, 2021)

I emailed PM and it sounds like they're never getting those motors in stock as they're not even ordering them. Guy told me they received PM-835s with 3ph motors already installed, though, but that does me no good since I already have one that's practically brand new


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## Ischgl99 (Mar 16, 2021)

That’s concerning they don’t stock motors for the machines they sell.  So basically if someone fries a motor for that machine, they are SOL...

I don’t have that mill, so don’t know what you need, but it might be a standard motor you can easily get.  I see from the manual for that mill that the base is not standard, but a standard motor may still fit and you might need to adapt it slightly.   Baldor has a lot of good information on their website.  If your motor does not have a frame size on the nameplate, you can take measurements and compare to this page and see what you have.  
For NEMA size motors. https://www.baldor.com/Shared/pdf/nema_chart_04.pdf

IEC (metric) motors. https://www.baldor.com/Shared/pdf/IEC.pdf

I made a control pendant for my mill and wired it into the VFD.  It is not that difficult to do and uses momentary push buttons for start and stop controls and a rocker switch for forward reverse using the three wire control method in the VFD, as well as a potentiometer for speed control.   I have a run/jog rocker switch as well, but have never found the need for jog yet and would eliminate that if I needed to rebuild it.


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## COMachinist (Mar 16, 2021)

Unless your going to cnc the mill with coolant, auto start, and all the bells and whistles of a CNC set up a BKAC 27d or the next one up for bigger than 2hp by just adding a switch or two you can get bump, Reverse on/off and auto. I have one on my 2hp. Belt grinder and one on my manual mill. I used a Hitachi 1.5kw on my 2hp CNC conversion mill. Only problem with anything from KB electronics their warranty and customer service sucks a big one, they are horrible. It took a month to just get an RMA to send a blown up 27d back for warranty Repair that took another month+.To just change speeds on a manual mill it is a good choice.for that and it will do up to 2x motor speed, and best of all you can have your install done in like a couple hours if you don’t like playing with software and building electronics cabinet’s Your making chips sooner, a lot sooner This is a good way to go and pray you don’t need customer support.
CH


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## pacifica (Mar 17, 2021)

COMachinist said:


> Unless your going to cnc the mill with coolant, auto start, and all the bells and whistles of a CNC set up a BKAC 27d or the next one up for bigger than 2hp by just adding a switch or two you can get bump, Reverse on/off and auto. I have one on my 2hp. Belt grinder and one on my manual mill. I used a Hitachi 1.5kw on my 2hp CNC conversion mill. Only problem with anything from KB electronics their warranty and customer service sucks a big one, they are horrible. It took a month to just get an RMA to send a blown up 27d back for warranty Repair that took another month+.To just change speeds on a manual mill it is a good choice.for that and it will do up to 2x motor speed, and best of all you can have your install done in like a couple hours if you don’t like playing with software and building electronics cabinet’s Your making chips sooner, a lot sooner This is a good way to go and pray you don’t need customer support.
> CH


Not sure if Hitachi is any better.  When I had a problem with my Hitachi vfd , I was told I would have to send it to Hitachi _at my expense_, they would *decide if the warranty covered the problem *and then it would be at least another month( vfd was one week old). Lucky for me the wire for the on/off had come loose so I easily fixed the problem.


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## COMachinist (Mar 17, 2021)

pacifica said:


> Not sure if Hitachi is any better.  When I had a problem with my Hitachi vfd , I was told I would have to send it to Hitachi _at my expense_, they would *decide if the warranty covered the problem *and then it would be at least another month( vfd was one week old). Lucky for me the wire for the on/off had come loose so I easily fixed the problem.


Yeah KB controls is about the same if you have a blow up and let the magic smoke out. I sent mine back USPS priority mail to make sure it arrived, along with insurance if it escapes the mail truck Some where along the trip to Florida, repair Center. Just saying if all he wants it is to increase/decrease rpms with out changing the belt then for cost you can’t beat the the KBAC 220vac single phase controlers.


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## pacifica (Mar 17, 2021)

COMachinist said:


> Yeah KB controls is about the same if you have a blow up and let the magic smoke out. I sent mine back USPS priority mail to make sure it arrived, along with insurance if it escapes the mail truck Some where along the trip to Florida, repair Center. Just saying if all he wants it is to increase/decrease rpms with out changing the belt then for cost you can’t beat the the KBAC 220vac single phase controlers.


I know the vfd I had from automation direct( about 7 years ago) was easier to program than the hitachi because it had far fewer parameters to worry about.


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## Joe-R (Mar 18, 2021)

Pcmaker said:


> I am thinking of buying a 3 phase motor for my PM-835S from Precision Matthews so I can have variable speed without having to keep changing belts on the step pulley. I need a 220v 1 phase input, 220v 3 phase output VFD, something that can reverse directions.
> 
> Any recommendations or is that something I should also talk to PM about and order it from them also?


Hi, 

From the operators manual for your mill, it looks like it uses a  "C" Face motor attached to a mounting ring made specifically for that mill. 
The motor should have a number and a letter that indicates which mounting size and configuration it is like: "56C" for example. 
If there is no number and letter for the mounting size and type, you can cross reference the measurements with most any motor manufacturer's specs to get the right configuration.

I would suggest buying an "Inverter Duty" motor, they are made specifically for use with AC Drives (VFD). 
The advantage of using an inverter duty motor is their ability to run at very slow speeds without overheating.
Non-inverter duty motors tend to get pretty warm at slow speeds because the motor fan doesn't turn fast enough to cool itself. 

Dura-Pulse AC Drives from Automation Direct are good drives IMHO, I have installed several of them in industrial plants with good results and they aren't too expensive.  I installed a 20 HP Dura Pulse drive about 10 years ago on a non- inverter duty machine and it is still working good, no issues so far. That particular machine never runs at really slow speeds so a non-inverter duty motor was OK in that case. 
I suspect you will want to run your mill at very slow speeds from time to time.  
You can use an external knob (potentiometer) to control the speed by changing one parameter in the drive, there are several good "How to" videos on YouTube on how to change the parameters for using speed control knobs as well as external start, stop, forward and reverse buttons/switches. (if you need to). 

Just my opinion but a 3 phase motor is the only way to go if you want really slow speeds, single phase motors loose nearly all their torque at slow speeds. Just throwing that out there, I realize you weren't entertaining that idea. 

BTW, I have found that the Dura Pulse AC Drives come factory set with good torque curves for machine tools, in most cases they don't really need fine tuning, I did have to tune the torque curve and ramp time for a conveyer system once but the factory setting is pretty much setup for machine tools like your mill.
You may wat to adjust the ramp up and ramp down times though, factory settings are something like 6 seconds if memory serves me right. 
You probably don't need the a brake resistor (dynamic braking) on the drive since your mill has a manual spindle brake. 

You probably could set the pulley system in the high speed setting and leave it, but still use the High Range/Low Range Cam Lever.

Kind of odd that Low Range is from 80 - 325 while High Range is from 660 -2720, nothing in there for speeds between 325 and 660?  
An AC Drive would solve that issue  (AKA: VFD, Sorry, I have always called them AC Drives for some reason).

Must be a little annoying that the spindle reverses direction between High Range to Low Range. I would definitely have a hard time getting used to that! 
But for the price of that machine, little upgrades and getting used to small quirks would be worth it in the long run.  

Almost forgot, most metric motors can be cross referenced to standard NEMA motor frames, the main difference is usually the length and diameter of the output shaft, most other dimensions like the bolt hole circle diameters for mounting will cross reference.
In other words, you should be able to get a standard 56C Face motor (for example) with a metric sized shaft
It may pay to measure the existing shaft diameter, some motors from overseas already have imperial sizes like 1-3/8 thru 1-5/8" for a 3 HP motor. 

Anyway, I hope this helps!! 

Have a great day!! 

Joe


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## Dart (Mar 18, 2021)

I don't agree that a Chinese VFD will not be good I have a real Huanyang 220v mono/220v tri 2.2kw on my router . The Huanyangs are good but they where cloned and the cheaper versions are crap. They are good documented and well made for the price. Price/ quality you don't find better.


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## Hunter9173 (Mar 20, 2021)

Ischgl99 said:


> That’s concerning they don’t stock motors for the machines they sell.  So basically if someone fries a motor for that machine, they are SOL...
> 
> I don’t have that mill, so don’t know what you need, but it might be a standard motor you can easily get.  I see from the manual for that mill that the base is not standard, but a standard motor may still fit and you might need to adapt it slightly.   Baldor has a lot of good information on their website.  If your motor does not have a frame size on the nameplate, you can take measurements and compare to this page and see what you have.
> For NEMA size motors. https://www.baldor.com/Shared/pdf/nema_chart_04.pdf
> ...


Do you have a built thread on this or know where to find information how to build one and wire it in ? If not that do you know of a place that this could be bought already assembled?


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## Ischgl99 (Mar 20, 2021)

Hunter9173 said:


> Do you have a built thread on this or know where to find information how to build one and wire it in ? If not that do you know of a place that this could be bought already assembled?


I haven’t done a thread on it.  It’s pretty simple, use the wiring diagram for your VFD as a guide.  This uses the three wire control method, so you will have a momentary start and stop push buttons, start is normally open contacts, and the stop normally closed and wired as shown in this drawing.  My VFD is a Teco 7300CV, so your wiring terminals might be labeled differently.







For the speed adjustment, you use a potentiometer suitable for your VFD and wire it in according to your manual, below is how to to it with the Teco. The speed adjustment is labeled as frequency indicator device.
	

		
			
		

		
	






I used a regular multiconductor cable for all the signal wires, you don’t really need to worry about shielded wire for the potentiometer since all the signals are low voltage and they are not turning on and off during operation, so it is unlikely you will get interference.  

You will need to change some parameters in your VFD so it knows this is how you are controlling it.  There should be a setting for three wire control as well as external speed reference that need to be set, otherwise it will think you want to control from the keypad.

Push buttons you can get from McMaster-Carr or Automation Direct.  I can’t recall where I got the potentiometer from, but you want one that has about a 270 degree swing from 0-100%.  Automation Direct I believe has speed scales for 0-100% that you can install, I just printed my labels for testing and never changed it.  The case is a run of the mill rectangular case with the top that comes off and the holes for everything was drilled where I wanted them.  

If you have any questions on it, or need clarification of any of this, feel free to ask.


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## Hunter9173 (Mar 21, 2021)

Thank you for the info. I currently have the TecoFM50 hooked up to a 3 phase motor.


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## Ischgl99 (Mar 21, 2021)

I believe the Teco FM50 has the same options for control as my 7300CV, so it should go smoothly.  Good luck with it!


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## Todd727 (May 9, 2021)

I have a TECO FM50 on my SB lathe.  It would be more than enough to have a potentiometer, REV/OFF/FWD and E-stop.  Also, very simple to set up.  I was buying the Hitachi WJ200 for my PM1440LB so I went ahead and ordered two.  Pretty much overkill for the mill.  

On another note, I have a SB lathe with VFD for sale...


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