# VFD Wiring Help?!



## jarrettbailey (Jul 7, 2020)

Hey everyone!

I finally got a lathe and a mill for my home shop and I bought VFD's to use them on 220 1ph. The mill I believe is more straight forward since it's just forward and reverse and the switch for it is easily accessed. I'm unsure of how to approach the lathe though. It's got a foot brake (brake is mechanical), forward, reverse, on, and off switches. I've not been able to find diagrams for this and I don't have (nor can I find) a manual for this lathe. Does anyone have any ideas or can you point me in the right direction. I'd like to simply use the lathe as though it was hooked to 3 ph power. I am not concerned with variable speeds or anything. I just want to use the functions of the lathe as they were originally designed.

Thanks in advance for the help!


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## ErichKeane (Jul 7, 2020)

SO you cannot have a switch in between the motor and the VFD.  Typically you just wire these to the inputs of your VFD, then program in the features you want.  You'll basically just want to gut the electricals of the lathe, and wire the switches to the VFD inputs.

In my case, I have a 3 position 'knob' that I use for fwd/reverse as well as 'on/off'.  I don't know what your panel looks like, but I'm sure you could use the existing knobs/buttons as inputs to a programmable VFD.


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## tazzat (Jul 7, 2020)

You cant use the lathe as though it was hooked to 3 ph power using a VFD..


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## pacifica (Jul 7, 2020)

jarrettbailey said:


> Hey everyone!
> 
> I finally got a lathe and a mill for my home shop and I bought VFD's to use them on 220 1ph. The mill I believe is more straight forward since it's just forward and reverse and the switch for it is easily accessed. I'm unsure of how to approach the lathe though. It's got a foot brake (brake is mechanical), forward, reverse, on, and off switches. I've not been able to find diagrams for this and I don't have (nor can I find) a manual for this lathe. Does anyone have any ideas or can you point me in the right direction. I'd like to simply use the lathe as though it was hooked to 3 ph power. I am not concerned with variable speeds or anything. I just want to use the functions of the lathe as they were originally designed.
> 
> Thanks in advance for the help!


I can understand wanting to keep it simple but a VFD has a number of functions you will want to use on a lathe, i.e. : slow startup, very slow speeds (less than 25 rpm) for threading or tapping, dynamic braking, infinite variable speed to eliminate cavitation, higher rpm's.


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## markba633csi (Jul 8, 2020)

Sounds like you might want an RPC for the lathe instead?  
-Mark


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## ErichKeane (Jul 8, 2020)

pacifica said:


> I can understand wanting to keep it simple but a VFD has a number of functions you will want to use on a lathe, i.e. : slow startup, very slow speeds (less than 25 rpm) for threading or tapping, dynamic braking, infinite variable speed to eliminate cavitation, higher rpm's.



Oh yeah, the VFD is vastly superior in a number of ways, I wouldn't do anything else on any single-motor device.  You can still use the standard 'control panel', you just have to wire the switches up as sensors instead.  Another thing the VFD can do (which I LOVE) is an emergency stop.  I can stop my lathe in about 1/10th of a second (I actually wasn't brave enough to put it lower than ~2/10ths for testing, since it was a violent stop) in the event of an emergency.

Also, my lathe shipped with the option for a 1700 rpm motor OR a 3500 rpm motor.  Since I have the VFD, i can do both


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## Cadillac (Jul 8, 2020)

tazzat said:


> You cant use the lathe as though it was hooked to 3 ph power using a VFD..



what would be the reasoning behind your thoughts? A vfd can absolutely power a 3ph lathe or anything else within the specs of the motor and vfd. Have 4 of them powering a lathe,Bridgepor, and two surface grinders.


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## tazzat (Jul 8, 2020)

Cadillac said:


> what would be the reasoning behind your thoughts? A vfd can absolutely power a 3ph lathe or anything else within the specs of the motor and vfd. Have 4 of them powering a lathe,Bridgepor, and two surface grinders.


Not the way he wanted to use it.. use the VFD as a 3 phase line in and run the lathe as stock using power/stat/stop on the lathe not connecting this up to the VFD


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## markba633csi (Jul 8, 2020)

Right, using the lathe as stock which opens/closes the motor wires is a no-no with VFD drives, but OK with a rotary phase converter
-Mark


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## jarrettbailey (Jul 10, 2020)

Well, I got it going! Wired the fwd/rev handle and the brake switch as an e-stop. Pretty pleased for now. Need to run it a while before playing with other features of the vfd!


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## Karl_T (Jul 10, 2020)

FANTASTIC!  Such joy when it works.

I suggest you look into a pot to control VFD speed as your next action item. Even if you have multiple speeds with gearing, this addition is SO HANDY.

Next look at getting a braking resistor. the lathe will take forever to spin down from high speed. this solves that issue.

Have fun!


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## jarrettbailey (Jul 11, 2020)

Mill hooked up and running as well! I do have a question: is there a way to program the vfd to show actual spindle speeds? If so, what parameters an I looking for to program, or what method to use? Thanks for all the help!


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## Karl_T (Jul 11, 2020)

Which brand VFD? Most have this.


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## jarrettbailey (Jul 11, 2020)

Huan Yang. Chinese, but like my daddy used to say, "poor man has poor ways"


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## Karl_T (Jul 11, 2020)

don't have that manual handy, sorry. if you are good at decoding their chinglish, I bet its in there. It would be under the display settings parameters.


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## mksj (Jul 11, 2020)

You can display either motor Hz or Motor RPM, there is an indicator light for each. How you get it to cycle to RPM and use that as a default is a mystery to me, I assume you use the up down buttons to scroll through the functions. Others VFD's you can set a scaling function and a default display value, so you can account for the final fixed drive ratio. An alternate that is often used is the output terminals (AM, ACM) of the digital frequency which gives a 0-10V/10mA voltage swing, this is used with a digital voltmeter that can be scaled to give a numeric RPM value. This is commonly used with factory VFD 2 speed mills and lathes,  the voltmeter has two inputs, each input is sclaed for the respective range and uses a switch to switch inputs when the gear is changed. So a bit more complicated and you need a separate power source for the meter. Some of the RPM voltmeters have 2 inputs, each scalable, alternative would be use resistors as a voltage divider. The decimal place can also be changed. These types of digital meters can be expensive.








						46.21US $ |Digital RPM indicator with 0 10V output 0 999999 smart digital tachometer rotate speed controller RPM meter with analog output|Current Meters|   - AliExpress
					

Smarter Shopping, Better Living!  Aliexpress.com




					www.aliexpress.com
				





			https://www.automationdirect.com/adc/overview/catalog/process_control_-a-_measurement/digital_panel_meters/1-z-8_din_size
		


An alternate is to buy an inexpensive tachometer that uses a hall sensor and a magnet, about $15-20, the magnet needs to be mounted somewhere on the spindle. You need a small power source for the tach, usually 12VDC.  Another option is to use a hand held tach for ~$20, and take a quick read of the spindle. You could also make a chart for the speed in each belt ratio and scale the value based on the Hz reading.








						Digital Red LED Tachometer 10-9999 RPM Meter Gauge + Proximity Switch Sensor USA  | eBay
					

Proximity output current: 20mA(For the sensor). Hall proximity model:NJK-5002C.  1 x NPN hall proximity sensor. Red LED Specifications Display:5 x 2cm red LED. Sensor wiring:brown(Power+),black(Test+),blue(signal).



					www.ebay.com
				







__





						Amazon.com : Neiko 20713A
					





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## B2 (Mar 28, 2021)

Hi Mark,  
I spend a long time looking for a high resolution tach in a small package.  $14.00 free shipping from China!  I purchased two and they both worked with a Hall effect sensor I purchased separately.   I have put one in my PM1440GT front panel, but I will never test out the higher digits!!!

https://www.aliexpress.com/item/32974138466.html?spm=a2g0s.9042311.0.0.27424c4dlY8Cn8      In case the link fails the add title can be searched at AliExpress.com    "6 Digits Digital Tachometer Speed Measure Meter"

Below I have copied pasted the add description: 

"The tachometer is small,cost-effective.it fit 5-999999 RPM speed motor,it can accurately measure the RPM of the engine and the various motors.    
Features & Specifications:    
    Power requirementC 8-15V    
    Measure range : 5-999999RPM.    
    Clear zero: Automatic,    
    Clear zero time: about 10s.the greater the RPM value,the longer the clear zero time.    
    Refresh frequency: 0.2-0.5S@120-1200RPM;0.25-0.6S@2400-999999RPM.    
    Measure indication:RPM<5000,±2;RPM>5000,±3.    
    Display:RED 0.56” LED    
    Input signusle signal,wet contactor signal,PNP or NPN proximity switch,HALL sensor.    
    Overall Dimension: 60x29x25mm,    
    Panel cutout Dimension: 58.5x27.5mm    
    Operating temperature: 0 to 50°C.    

Packaging include:    
    Tachoneter x 1 (come with 4pin cable)"

Dave


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## B2 (Mar 28, 2021)

Wow! 

Not for sure where the smiley faces came from!  Embedded in the web page script?  I should have pasted the description to notepad and then copied from there!

"Power requirementC 8-15V"

"Input sign: Pusle signal, wet contactor signal, PNP or NPN proximity switch, HALL sensor."


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