Thread: VFD for 3 Phase Mini 30

Hi Bob,
Thanks for that, shows how good my memory is......I thought it just said "dont do it"

Hi Graham,

3 HP DIGITAL 240V to 415V 3 PHASE INVERTER CONVERTER FOR BRIDGEPORT MILL LATHE | eBay

Now traditionally it has been hard to get reply to an email from him.*
He also seems to not understand that we dont have to pay VAT.
Maybe things have improved?

I've also read about the old motors and vsds but am yet to have an issue. I run three old motors, one I dont know the age of runs on 240V delta, two are likely 1960's if not before, one of those is runs on 415V in star(on the 415V teco) the other I havent rewired so runs wired for 415V star on a 240V VSD. I dont tend to run those machines at anything other than 50Hz unless I am testing settings for someone and then wont go above 60hz but will play around below 50. I'm yet to have an issue but you never know.

And there is yet another option. You could run your motors on a 240V vsd and put up with the power lose(call it 1/2). Though as you want to be able to run the motor at 25hz I doubt thats a good idea as you'd likely have something around .75hp(if that).

Stuart

p.s. Thats the guy Graham, I type slow

*I've just been back through my emails and he isnt as bad as I remember except for one which 3 weeks to get a reply, the other 5 where answered the same or following day. Though I recall neksmerj who also has one had issues with him also.
I've had mine since 5/8/10 though it likely only has a couple of 100 hours on it.

Originally Posted by gorriss

Hi Stuart

I didn't think you could get a VFD that did 240V single phase to 415 3 phase? That would be a great option because obviously I can keep my existing motors - cheaper all around and less work.
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.
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I have heard that VFDs can damage older motors. Apparently you should preferably use inverter rated motors? My motors are probably around 1980 vintage.

I am running a circa early 1960s 1/2 HP Macpherson 3-Phase 415V motor on a 1.5 kW "240V single-phase to 240 3-Phase" VSD and it has worked fine for the last two years but the motor lacks guts because the 240 V 3-phase output of the VSD when applied to the motor does not generate as much torque as when driven by 415V. I will soon be upgrading that motor to a 1 HP "240v 3 Phase" OR "415V 3 Phase motor" that should have more than enough grunt.

Originally Posted by BobL

I am running a circa early 1960s 1/2 HP Macpherson 3-Phase 415V

Why? not game to dig the star point out of 50 year old windings?
Thats why my Hercus drill is running in 415 .

If it ever worried me I could move the Hercus onto the 415V VSD and the shaper to the VSD off the hercus as the shaper motor has the star point bought out. Not as much of as issue for me I guess as the Hercus motor is at least 2hp so I still have 1hp.

Stuart

Originally Posted by Stustoys

Why? not game to dig the star point out of 50 year old windings?

Yeah - did that on another old Macpherson and twas a right PITA.

Just before I installed the VSD on the Hercus I was promised a 240/415V delta/star motor so I wired the Hercus up "as is" till I got the new motor. After more than 12 months of promises the promise fell through and I started a search for another motor - anyway 21 months later I now have 2 of them so I can finally switch the Hercus back to full grunt+.

Originally Posted by Stustoys

3 HP DIGITAL 240V to 415V 3 PHASE INVERTER CONVERTER FOR BRIDGEPORT MILL LATHE | eBay

I've also read about the old motors and vsds but am yet to have an issue. I run three old motors, one I dont know the age of runs on 240V delta, two are likely 1960's if not before, one of those is runs on 415V in star(on the 415V teco) the other I havent rewired so runs wired for 415V star on a 240V VSD. I dont tend to run those machines at anything other than 50Hz unless I am testing settings for someone and then wont go above 60hz but will play around below 50. I'm yet to have an issue but you never know.

I emailed a guy at Teco in Perth about this device and he replied and said 240V in 240V out no question. I think this device must be a static inverter with a VSD as well, sinec apparently a VSD can't up the voltage. I looked at a static inverter for sale near me (Polyphaz .55/4) already. I rang Polyphaz and they said I need a rotary converter and the static inverter would probably not start my machine. Is any one using the Drives Direct Inverter (see link above) for 3hp motors as I want to do?

Graham

Graham, this forum member has imported one from Direct Drives, I'm not altogether sure whether he has actually got it wired up and working.

If you start reading here:

https://www.woodworkforums.com/f65/24...se-vfd-128758/

He also has several other threads on this subject, so a search would find those if you want further details.

Originally Posted by gorriss

Is any one using the Drives Direct Inverter (see link above) for 3hp motors as I want to do?

Yes. Me.

Originally Posted by Stustoys

Just to had to the confusion. At your price of $550-$650 what may work for you is a Teco from the UK that has been modified for 240V single phase input - 415V 3 phase output. I have one. Its the one I switch the output on in fact. Working fine so far, I doubt I would go this route again but it could be an option for you.

The Teco guy is correct, Teco doesnt sell a VSD that "ups the voltage". It is a modifaction done by the guy in the UK. As I understand it the modifaction uses a 415V-415V Teco VSD with a voltage double added to the front end. But I really dont know.

Stuart

This might give you some ideas.
https://www.woodworkforums.com/f65/vsd-enclosure-129337/

I should add it depends a little on what you intend to use this machine for.
If you are going to earn a living with it I would think about trying it on 240V*. Then switching one or both motors out as needed. As Drives Direct is the only guy I know of modding these, that could be an issue if it drops dead. If its just for a hobby then that wouldnt be the end of the earth.

Stuart


*which as I said earlier likely wouldnt work for you, but it depends

Thanks again all for your help. I want the full grunt of at least 3hp, so I don't think running 415V motors on 240V will work for me. I have emailed the guy in UK about his VFD. If it does the job it is definitely my best option as I also have a pulley that wont fit the 90L motor so that's more complication (although I am investigating a 100L frame 3Kw motor that may still work with a 2.2Kw VFD? That will be more $ too!).

I was just a little cautious about your application (Stuart) because I think you are using a smaller motor, but I could be wrong?

Graham

Originally Posted by gorriss

I want the full grunt of at least 3hp

ok so the cheapest easiest option is out then.

Originally Posted by gorriss

although I am investigating a 100L frame 3Kw motor that may still work with a 2.2Kw VFD?

If you bought a new 3kW 240V motor you can get cheap 3kW 240V vsd's.
Though you start to run into problems with suppling the current required. Will the machine take it?
I think running a 3kW motor on 2.2kW vsd is doable but I'm not 100% on that.

Originally Posted by gorriss

I was just a little cautious about your application (Stuart) because I think you are using a smaller motor, but I could be wrong?

Both the motors I currently run on the 415V VSD are 3hp.

Hope I'm being more helpful than adding to the confussion.

Stuart

Thanks Stuart I think that really answers my question. You are successfully running 3hp (at least one old one too) motors on the 415V VFD much like I want to do. Hopefully I will hear from Drives Direct soon. It is really quite an economical and simple solution for me. I guess I could actually still use the 2 speeds of the 4 pole motor to vary speeds even though I can do it with the VFD. The only downside is more switching on the machine which just means more care to make sure they are switched correctly when I turn on the VFD.

I just had a look at your original post showing your setup. I am hoping mine can effectively be much simpler. Please tell me if I have this wrong but I plan that:
1. The VFD will be hard wired to its own 15 Amp circuit with its own breaker to turn the VFD on/off.
2. One 5 core cable will be used to send 415V three phase from the VFD to my machine.
3. I will (effectively) have a selector switch on the machine which allows a direct connection between VFD and one motor only at any time.
4. All powering on/off and speed variation of the machine will be done from the VFD itself (no need of remote switching etc)

Graham

Originally Posted by gorriss

I guess I could actually still use the 2 speeds of the 4 pole motor to vary speeds even though I can do it with the VFD.

Something I havent tried but if I was doing what you are doing I would certainly leave it as an option until I was happy with the motor power at 25Hz.(or 100hz if you wire it for low speed)

Originally Posted by gorriss

The only downside is more switching on the machine which just means more care to make sure they are switched correctly when I turn on the VFD.

Yes, If you thought it nessary you could fit a door over the controls on the machince along the lines big shed(?) was talking about in an earlier post.

Originally Posted by gorriss

I just had a look at your original post showing your setup. I am hoping mine can effectively be much simpler.

Mine only looks complicated as I've run the controls to the machine. Yours shouldnt need to look anything near that bad

I perfer to use the factory controls were possible, others bin the controls and start over.

Originally Posted by gorriss

1. The VFD will be hard wired to its own 15 Amp circuit with its own breaker to turn the VFD on/off.

As long as the breaker isnt to far away. (I'd prefer a switch close by the VSD, but thats your call)

Originally Posted by gorriss

2. One 5 core cable will be used to send 415V three phase from the VFD to my machine.

Why 5 core? (unless you have it already)

Originally Posted by gorriss

3. I will (effectively) have a selector switch on the machine which allows a direct connection between VFD and one motor only at any time.

yes
I assume you currently have an ON/OFF switch for one motor and a 1/off/2 switch for the two speed motor. Anything else?

Originally Posted by gorriss

4. All powering on/off and speed variation of the machine will be done from the VFD itself (no need of remote switching etc)

Depends where the VSD is going to be mounted. I would want at least a stop button some where as the control buttons are a little on the small side if you were in a hurry.
Also while you can control speed with the keyboard I think you will find a pot much easier. I've only even used an external speed pot. I dont think its as easy to fit an internal speed pot to the Teco as it is on other drives. Unless you just want fixed speeds and you can do that with switches.

Stuart

Originally Posted by Stustoys

Why 5 core? (unless you have it already)Stuart

The machine has a 5 core cable for 3 phases, 1 neutral, 1 earth. I thought that was normal?

Originally Posted by Stustoys

I assume you currently have an ON/OFF switch for one motor and a 1/off/2 switch for the two speed motor. Anything else?Stuart

My machine has ON/OFF for one motor and 1/OFF/2 for the other as you say. It also has 2 big switch boxes on the other side (1 for each motor) that has 3 buttons for ON, OFF, RESET.

Originally Posted by Stustoys

Depends where the VSD is going to be mounted. I would want at least a stop button some where as the control buttons are a little on the small side if you were in a hurry.Stuart

Yes a stop button sounds like a good idea even though machine does not currently have emergency stop button.

Originally Posted by Stustoys

Also while you can control speed with the keyboard I think you will find a pot much easier. I've only even used an external speed pot. I dont think its as easy to fit an internal speed pot to the Teco as it is on other drives. Unless you just want fixed speeds and you can do that with switches.Stuart

OK maybe I will do a speed pot too.

So is it OK to have a flex type cable just sitting on the floor between VFD and machine? I guess it is effectively the same as an extension cord to any other machine. Don't want to trip over stuff, but it's the only option I spose.



Graham

Originally Posted by gorriss

The machine has a 5 core cable for 3 phases, 1 neutral, 1 earth. I thought that was normal?

You wont have any use for the neutral.
Its there so you can get the single phase voltage from one of the 3 phases. But you cant do that with a VSD. Though if thats the wire you have it will be fine.

Originally Posted by gorriss

My machine has ON/OFF for one motor and 1/OFF/2 for the other as you say. It also has 2 big switch boxes on the other side (1 for each motor) that has 3 buttons for ON, OFF, RESET.

The 2 big switch boxes will need to be removed or at least the internals bypassed.

Originally Posted by gorriss

So is it OK to have a flex type cable just sitting on the floor between VFD and machine? I guess it is effectively the same as an extension cord to any other machine. Don't want to trip over stuff, but it's the only option I spose.

Yes, though there is a limit on the length of cable you can have but I cant recall what it is ATM.
Could you drop the power from the roof/ceiling?

Stuart