VFD type

[gadabout]

Hi all!
I have this motor (see attachment) that I want to fit to my mill for the spindle drive. I would like advice as to what VFD might be suitable. It has to run on 240v 50hertz single phase. I would like it to talk to Mach3 as well. Also I’d like one with the twiddly knob speed adjuster.
Thanks
Mark

[Thor]

 According to the nameplate it can operate on 240V if configured as Delta so a 240V single phase to 3-phase VFD should get the motor running, don't know how to get Mach3 to control its speed.

Thor

[Jo]

A VFD that can drive a 220V (230V) 2.2KW motor, you will need to wire your motor in delta 

Speed control on a VFD normally uses a Potentiometer mounted on the front panel to provide a voltage to vary the speed . If you look in the instructions one of the software controllable options is to use an external Pot instead of the internal one and this is available on the VFD input/output pins. The VFD provides a 0V and a normally +5V output which you wire to the two ends of the Pot, then you take off a variable voltage from the centre tap to control the VFD speed output.

To use Mach 3 to control the VFD you need a variable voltage which goes from 0V to +5v (or whatever your VFD uses as a speed control voltage). Some Mach 3 control boards provide this output as standard, some control boards don't so you have to add an extra PWM to 0V-XXv¹ board. You need a common ground (0V) between the VFD and the Mach 3 board and then limit the Mach 3 board output voltage to the voltage required by the VFD.

You will not get a VFD that will let you use both an internal and external voltage source for speed control concurrently so you need to pick one and program the VFD to use that as the input. If you want to change over to a different control source you will need to reprogram the VFD. This reprogramming is simple (once you understand the odd ways they work  )

Jo

Note: UK mains is not 240V AC and if you measure yours at 240V you need to phone up the supply company and get it reduced. It should be 230V

1. This is probably 5v, but most Mach 3 boards provide 10V and you control the voltage down to 5v in the Mach 3 software.

[Don1966]

Jo is correct the VFD can be programmed to except external control from different variables, like current input, voltage input, freq input, communications input. The voltage input Jo mention will depend on the supply voltage the VFD using for the external potentiometer control. Usually 5 volts. If you have 10 volts that can also be used with a voltage divider network usually two identical resistors in series tapped in the middle to get the 5 volts. These resistors should be 10 times larger then the input resistance of the input. Your motor looks to be a 1.5 HP and getting a VFD for single phase input and three phase output is limited to 1.5 HP at 230v if I remember correctly. Hope that helps.

Regards Don

[gadabout]

Hi all! ,
Thanks for the replies!

Jo, I live in Australia , our mains supply is 240v

Don, the plate states it is 2.2kw that converts to approx 3 hp

So I it looks like a cheap VFD from you know that auction place would work ok

Thanks
Mark

[Jo]

Only Western Aussie and Queensland remains on 240V (Queensland is transitioning to 230V).

So what is the difference? Not a lot: That extra voltage causes the old types of light bulbs to glow brighter and consequently sometimes they do not last as long  Modern bulbs with their own internal Power correction thingies (PSU) will cope.  But generally the voltage standards state a 10% tolerance on actual voltage so most devices can get away with 210V AC or even as high as 250V AC. (I won't bore you on the effects of over voltage and premature aging as none of us wants to admit to premature aging  )

Cheap Chinese VFD's may be as reliable as other VFDs as often what you get from China is the overruns of the European/American production runs.

What should you buy? If you buy from a reputable local supplier you get support. If you buy directly from China you might get rejects ¹ but then again it might last as long as an expensive unit or may (if it fails) damage other stuff. You make your choices and you live with it.

Jo

1. I recently brought a cheap Chinese copy of a rotring pencil: unbelievable they could not cut a straight thread  but I can live with a bent pencil. I wouldn't want to live with dangerous electrics 

[gadabout]

Jo, thanks for your reply!
I have not heard about the changing of voltages here, interesting!
I live in the state of Tasmania and as far as I am aware we are still 240 v I will have to investigate!
Fair call on the cheap VFD vs buying from a local ,will keep that in mind
Regards
Mark

[Don1966]

My mistake it’s more of 2.5 HP according to the current.
2200/746 * .80=2.359 Hp
Don

[john mills]

here in melbourne it is meant to 230 volts but with solar systems around voltage can vary a lot .had low voltage so things cut out and high
250 volt power company lower the voltage so high voltage from solar supplys don't  cut out but when the sun goes the voltage drops too low

i recently fitted a vid for 1.5 kw from a good brand (it is still made in china)the supplier lists one for 240v ac  +_10%motor rating 2.2 kw
or 3 hp 
john

[gadabout]

Thanks John,
Do you have a link to that supplier?

Mark

[Don1966]

It seems I made another mistake I have to correct. You can go up to 40 HP with single phase input which I would not recommend because of the current draw. A three HP VFD  https://dealerselectric.com/176111-00-.asp

Regards Don

[Admiral_dk]

I'm sorry Don, but I think you made one more :

These resistors should be 10 times larger then the input resistance of the input.

It should be the Input Resistance that is 10 times larger than the resistors / the resistors should be 10 time smaller than the Input Resistance .... If not, the Input will load the resistors too much.
The way I was taught, was to keep the current in the resistors 10 times higher than the current into the Load (Input in this case).

I will not comment on the rest as you have many years of experience with VFD's and I have none.

Best wishes

Per

[Don1966]

I'm sorry Don, but I think you made one more :

These resistors should be 10 times larger then the input resistance of the input.

It should be the Input Resistance that is 10 times larger than the resistors / the resistors should be 10 time smaller than the Input Resistance .... If not, the Input will load the resistors too much.
The way I was taught, was to keep the current in the resistors 10 times higher than the current into the Load (Input in this case).

I will not comment on the rest as you have many years of experience with VFD's and I have none.



Best wishes

Per

Your right Per my brain was not engaged because I screwed up on all. I was taught the same.  No excuse other then been on meds from surgery. Sorry for the misinfromation people.


Regards Don

[dieselpilot]

I would like it to talk to Mach3 as well. Also I’d like one with the twiddly knob speed adjuster.

How is the VFD intended to be controlled? Is Mach controlling this drive, or is the mill also used manually so needs a pot speed reference when Mach is not running?

Most VFD use 0-10V input. It's been ages since I looked at MACH, but I recall most breakout boards are 0-5V. Specific hardware was required to get 0-10V spindle signal.

Adding the ability to use a pot without the CNC control will take some effort as the CNC  should also have enable other signals connected. Potentiometer control could be worked out if absolutely required.

VFD aren't picky about input voltage, unless it gets out of range, which is a wide ~180-265VAC for a 200V class drive. Mains voltage should fall within spec, but that's not relevant to the VFD. My drives trip on overvoltage in the spring when the load on the grid drops. It hovers near 250V most of the time. I had a VFD die this year, but I knew it was coming. When plugged in, it took longer and longer to power up until it just didn't. It was a <100USD Allen Bradley purchased used from Ebay. I replaced it with a new old stock Control Techniques Commander SL 1.5kW from ebay for under 80USD. All my VFD have been cheap used from ebay, but name brand.

[gadabout]

Well, I will initially use it manually , but I would like the option somewhere down the track to stop ,start it and control the speed via Mach so was trying to cover my bases!
Atm I’d like to push the button to start the mill and twiddle the knob to get my desired rpm’s

Thanks

Mark