# vfd use



## JT. (Dec 28, 2012)

so i can use all the speeds and speed directions with the lathe commands when the lathe is running on a vfd powersorce 
ore do i need to use the vfd  for rotation direction and second speed


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## Kennyd (Dec 28, 2012)

You can set the VFD to control a range of speed (actually frequency).  Mine on the lathe is set to to vary between 30 and 60 Hertz.  If you need more then you can change the belts and/or use the backgear.

Your question is not very clear, but in general you cannot use the lathe's (or mill's) existing controls since they will disconnect the motor from the VFD power source-and that is a huge no-no.  You can possibly rewire the existing controls to operate the VFD.

Clear as mud?


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## Ray C (Dec 28, 2012)

I do something similar to KennyD but I still tend to use most of the gears on the machine just as I normally would.  This is purely a matter of preference (neither is right or wrong).  The advantage is that you tweak the speed up/down just a tiny bit (or as much as you want) to get the perfect speed and make best use of the motor's torque.  Let's say you have a gear that's set for 840 RPM but your piece would really like to be cut at 800 RPM... -No problem, just tweak the VFD down a tiny bit.

It's OK to power-off the supply to the VFD but, it's not OK to put a switch in between the VFD and the motor.  What many people do (including myself) is, connect the motor's power supply input lines to the input of the VFD then, put the VFD output to the motor input terminals. This way, your normal on/off switch still works as does any other electronics that might be present in the equipment. This is a safe/easy approach.  Complications arise when the equipment normally had 2-speed motors and you need the schematic to see how to best deal with the wiring.

Ray

EDIT:  It's generally not a good idea to run a motor at speeds less than 75% of it's nominal rating since older motors may rely on fan cooling and the fan won't spin fast enough to keep it cool.  Unless the motor states otherwise, it's not advisable to exceed 60Hz.  These are ballpark guidelines (45 to 60 Hz) and you need to check the specs on your motor to be certain.


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## woodtickgreg (Dec 28, 2012)

Kennyd said:


> You can set the VFD to control a range of speed (actually frequency).  Mine on the lathe is set to to vary between 30 and 60 Hertz.  If you need more then you can change the belts and/or use the backgear.
> 
> Your question is not very clear, but in general you cannot use the lathe's (or mill's) existing controls since they will disconnect the motor from the VFD power source-and that is a huge no-no.  You can possibly rewire the existing controls to operate the VFD.
> 
> Clear as mud?



Wow, I'm glad I saw this. I am getting ready to purchase a vfd for my heavy ten restoration and I wanted to use the original switch, so if I am understanding this right the original cuttler-hammer switch cannot be used with a vfd as it will disconnect power fed from the vfd and that's not good. Now I am unsure what I will do. Also if I am understanding this right, the only way to turn the lathe on and off is with the vfd? I kinda like the idea of being able to reach up and hit the kill switch for safety's sake. And then there's your last statement, "you can possibly rewire the controlls to operate the vfd" Now I'm intrigued, can the original switch be used to operate the vfd? That would be great if it could.


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## Kennyd (Dec 28, 2012)

woodtickgreg said:


> Wow, I'm glad I saw this. I am getting ready to purchase a vfd for my heavy ten restoration and I wanted to use the original switch, so if I am understanding this right the original cuttler-hammer switch cannot be used with a vfd as it will disconnect power fed from the vfd and that's not good. Now I am unsure what I will do. Also if I am understanding this right, the only way to turn the lathe on and off is with the vfd? I kinda like the idea of being able to reach up and hit the kill switch for safety's sake. And then there's your last statement, "you can possibly rewire the controlls to operate the vfd" Now I'm intrigued, can the original switch be used to operate the vfd? That would be great if it could.



Greg, there are many threads on this.  You simply rewire your machine's switch for low-voltage control so it will operate the VFD's F-N-R functions, and you can add a pot (potentiometer) to control speed as well.

Here is a thread to read: *http://www.hobby-machinist.com/showthread.php/8009-A-VFD-write-up-for-a-Webb-Mill?p=66247#post66247* as an example even though he used a external switch.

Another one: *http://www.hobby-machinist.com/showthread.php/7757-Wire-a-drum-switch-to-a-Teco-FM50*

Anyway, I suggest you start your own thread and provide details and pictures of your motor and switch when your ready.  We can also suggest the proper VFD with that info.


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## woodtickgreg (Dec 28, 2012)

Kennyd said:


> Greg, there are many threads on this.  You simply rewire your machine's switch for low-voltage control so it will operate the VFD's F-N-R functions, and you can add a pot (potentiometer) to control speed as well.
> 
> Here is a thread to read: *http://www.hobby-machinist.com/showthread.php/8009-A-VFD-write-up-for-a-Webb-Mill?p=66247#post66247* as an example even though he used a external switch.
> 
> ...



Very good, I was hoping that I could use the switch to controll the vfd. Thank you for the reply, I will post pics of the motor tag and the switch in a new thread. Thanks for the advice.


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## JT. (Dec 29, 2012)

after reading my post a bearly understand my self what i wrote :thinking:

so  here i go again 

on the old continent we got 220V mono for home use   3x220v (old configuration )  ore 3x380v+N (indistrial power )
i bought a lathe withe a 3x220 V motor  with a transformator so it runs on the 380 V now 
in my workshop where i want to install the lathe i only got 220V mono 
i can install the 380 option but then i need to run a 380v line to my workshop ( instalation in electrical cabinet + 60 yrds to my shop with al the hardware and manhours i think 500-700 $) 
so i was thinking on the VFD option so i can run it on the 220V mono (250 $) but way more controle on the lathe speed etc. )
only drawback is from what read here is that i can not use the original lever without rewiring it .
i understand i can rewire it so the originale lever  can act like a the remote controle from the VFD 
i probably lose the dual speed  function from the lever but  F/O/R will do also 
how do i do that ?


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## Kennyd (Dec 29, 2012)

OK JT now we are making progress!

Your 220v "Mono" is what we call single or 1 phase power, and your 3x220 is what we call 3-phase.

Yes, you will wire the motor directly to the VFD, and then you will have to identify what contacts in you switch are open/close in the different positions with a ohm-meter or simple continuity tester.  You will loose the dual speed function, but thats OK.

Does your machine have two motors?  A and C in the diagram?  Can you provide a key/description for the other letters please?


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## JT. (Dec 30, 2012)

Kennyd said:


> OK JT now we are making progress!
> 
> Your 220v "Mono" is what we call single or 1 phase power, and your 3x220 is what we call 3-phase.
> 
> ...



nope only one  .
A main motor
B switch /phase inverter 
C cooling pumpmotor 
D cooling pump switch
E power supply
F minima of tension                     
G main switch


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## JT. (Dec 30, 2012)

so i need a VFD 2.2KW  some one got an idea if the VFD on flebay is any good ?http://www.ebay.co.uk/itm/UPDATED-N...ial_Automation_Control_ET&hash=item43acaa0403

ore is thise a better one 

http://www.ebay.co.uk/itm/3-HP-DIGI...ial_Automation_Control_ET&hash=item589a2d67d7


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## Kennyd (Dec 30, 2012)

JT. said:


> nope only one  .
> A main motor
> B switch /phase inverter
> C cooling pumpmotor
> ...



So you are not going to use the coolant pump? (that is a motor, so you do have two)


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## Kennyd (Dec 30, 2012)

JT. said:


> so i need a VFD 2.2KW  some one got an idea if the VFD on flebay is any good ?http://www.ebay.co.uk/itm/UPDATED-N...ial_Automation_Control_ET&hash=item43acaa0403
> 
> ore is thise a better one
> 
> http://www.ebay.co.uk/itm/3-HP-DIGI...ial_Automation_Control_ET&hash=item589a2d67d7




The second one you linked looks like a re-labeled Teco model and is probably a better unit, the first one is a China made cheapot, they seem to work OK according to those who have them but they can be a challenge to program since the manuals are very poorly written.


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## Ray C (Dec 30, 2012)

Looks like your motor has two sets of center-tapped windings giving 4 modes:  Forward low-speed, forward high-speed, reverse low-speed and reverse high-speed.  One set of wires supplies power to the full winding and the other set of wires supplies power to the half-winding (center-tap).  The switch is capable of reversing the polarity of either of the sets which gives you the forward or reverse function.

You have a problem on your hands because a VFD only has one set of output lines and the motor requires two sets of input lines.  No... You cannot use two VFDs to get around this problem if that is what you are thinking.

I personally think the best solution, is to abandon one of the sets of wiring.  In this case, you would connect the VFD output to the full-winding input lines of the motor.  From there, you would use the VFD's frequency/speed and forward/reverse function to control the motor.


Ray




JT. said:


> after reading my post a bearly understand my self what i wrote :thinking:
> 
> so  here i go again
> 
> ...


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## Ray C (Dec 30, 2012)

Hard to say...

I have 3 VFD's in my shop.  Two are expensive ones from Automation Direct and one is the same as the inexpensive one (65lb UK) shown in the first link.  All work well and have been very reliable.  The adjustable parameters for all of them are identical and so are main characteristics of the board such as placement of power headers etc.  For my particular units they are probably repackaged versions of the same thing or, one is a knock-off clone of the other.  Either way, they both work well.

Ray




JT. said:


> so i need a VFD 2.2KW  some one got an idea if the VFD on flebay is any good ?http://www.ebay.co.uk/itm/UPDATED-N...ial_Automation_Control_ET&hash=item43acaa0403
> 
> ore is thise a better one
> 
> http://www.ebay.co.uk/itm/3-HP-DIGI...ial_Automation_Control_ET&hash=item589a2d67d7


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## Ray C (Dec 30, 2012)

If you decide to use the technique mentioned earlier in post #13, the output of the VFD would be connected to the input lines on the motor marked as PA, PB and PC.  Those wires connect the full edges of the delta and thus represent the full-length winding.

To verify this, with the motor completely disconnected from the power lines, connect an Ohm meter between PC and GB and take a reading.  Then connect the meter between PC and PA.  The first reading should be much less (approximately 1/2) of the second reading.

Once you've identified PA, PB and PC, the Ohm meter should read about the same when connecting anywhere between any of those lines and they probably won't vary much more than approximately +/- 10%.

You must properly identify PA, B and C as if you don't, you could end-up with a dead-on short and fry one of the windings.  To be on the safe side, you might consider temporarily installing circuit breakers on each of the feed lines to the motor.  That will act as a safety mechanism in case you get things wrong.

If you are not comfortable doing this, please get someone qualified to be with you to help you.  

Ray


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## JT. (Dec 30, 2012)

wil run it without cooling for now 
ore i change the pump to mono  ore a small VFD just for the pump 

opened up the lathe and got al ot smarter now 
motor is already marked wiht high and low speed 
right side (gray wires are high speed )
left side  (blue wires are low speed )






if the normal high speed(2800 rpm/50hz )  is 45 rpm -1000 rpm i wonder how low /high i can go with the VFD

got the oem run/off/reverse switch out also to rewire it for the VFD remote controle









last pic shows that the other wires are  the power lines 
so i connect the VFD direct to the high speed on the motor 
then run fw/off/ rev  wires to the switch  i need to figger out where to connect what where


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## JT. (Dec 30, 2012)

Kennyd said:


> The second one you linked looks like a re-labeled Teco model and is probably a better unit, the first one is a China made cheapot, they seem to work OK according to those who have them but they can be a challenge to program since the manuals are very poorly written.



yes probably teco that is what the sell also 

 Q1;   they got a basic and  a advanced VFD 
the advanced  give more torque at low speed is this neede ore not 
 Q2: ex can you run a 2hp motor on a 3hp VFD


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## Ray C (Dec 30, 2012)

It is better to have the advanced one that has constant torque.

Yes, you can run a 2 HP motor on a 3 HP VFD but, you must program the VFD to limit the Amperage to the value printed on the label of the motor.  In the picture, I can only see one of the numbers that looks like 5.4 / ---.  Use the higher of the two numbers.

With a VFD, you should not run the motor at speeds above what is printed on the label of the motor.  What Country are you in?  You probably have 50 Hz.  When you program the VFD, you should set the maximum frequency to 50 Hz.

If I were you, I would disconnect the blue input wires and cap each one off with a wire cap and electrical tape.  Do the same thing with the gray wires.

Connect new wires from the output of the VFD to the terminals on the motor where the gray wires were connected.

Yes, you could get a small VFD for the pump motor or replace it with a single-frequency motor.

Since the motor is 3 HP and you have a 2.2kW VFD, you must supply the VFD with a 20 Amp power line.




JT. said:


> yes probably teco that is what the sell also
> 
> Q1;   they got a basic and  a advanced VFD
> the advanced  give more torque at low speed is this neede ore not
> Q2: ex can you run a 2hp motor on a 3hp VFD


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## JT. (Dec 30, 2012)

the 1000 rpm is morethen enuff for me but i like very low speed sometime
the motor is only 1.8 hp max   . 5.4 A
yep whe got 50 hz


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## Ray C (Dec 30, 2012)

You will be able to get slow speed by turning the knob on the VFD.  The VFD will also let you go faster than 50 HZ but the motor might not like that because it may only be balanced for operation up to 50Hz.





JT. said:


> the 1000 rpm is morethen enuff for me but i like very low speed sometime
> the motor is only 1.8 hp max   . 5.4 A
> yep whe got 50 hz


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