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VFD extension

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VFD extension

Postby wallace » 03 Apr 2018, 16:42

Hi all, I'm just about to start another Wadkin Lathe and wanted some electrickery advice. I put a vfd in the last one I did and want to improve its useability on this next one. The cheap vfd I got had a 2m extension which enabled me to fit it nicely into the control box door. On this one I thought it would be good to have the control pad on a little box that could be move along the bed or near outboard turning. The extension ribbon looks quite fragile so I wondered if I could remove the ribbon and replace it with some nice flexible 8core or something. Doe that make sense?
Also is it possible to also use the existing momentary on/off buttons
wallace
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Re: VFD extension

Postby 9fingers » 03 Apr 2018, 17:08

wallace wrote:Hi all, I'm just about to start another Wadkin Lathe and wanted some electrickery advice. I put a vfd in the last one I did and want to improve its useability on this next one. The cheap vfd I got had a 2m extension which enabled me to fit it nicely into the control box door. On this one I thought it would be good to have the control pad on a little box that could be move along the bed or near outboard turning. The extension ribbon looks quite fragile so I wondered if I could remove the ribbon and replace it with some nice flexible 8core or something. Doe that make sense?
Also is it possible to also use the existing momentary on/off buttons


All depends on the connectors at both ends of the ribbon. Normal flat ribbon wiring is form of flexible printed circuit board and laminated in plastic. Quite difficult to make connections to.

The control mode with NO start and NC stop buttons you are suggesting is known as three wire control. It depends if the inverter supports 3 wire control or not. even if it does you will likely have to re-programme the inverter to accept this mode. It will be a case of reading the manual carefully.

Bob
Information on induction motors here
https://drive.google.com/file/d/1dBTVXx ... sp=sharing
Email:motors@minchin.org.uk
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Re: VFD extension

Postby wallace » 03 Apr 2018, 20:32

thanks Bob
wallace
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Re: VFD extension

Postby wallace » 09 May 2018, 12:11

I have just about finished another lathe and I am fitting the vfd. The guys budget only allowed for a cheapo vfd which I have used in the past and they seem to work ok. I am having issues, they are straight forward to wire up and are factory set for basic use straight out the box. The issue I'm having is it runs up to speed with no belt on but as soon as I install the belt it runs really slowly.
I wired the motor direct to power and it runs fine.
My 3 phase supply is via a static converter, I have used better quality vfd from Bob in the past which worked from my supply fine.
I tried running another lathe whilst using the new one but I get an error code
wallace
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Re: VFD extension

Postby 9fingers » 09 May 2018, 12:43

I've not had an inverter that is fussy about the input. In fact I often test 3 phase 415v inverters with a single phase 415 from a transformer and they behave ok.

Running with a pilot motor is a sound idea to me but you should get a clue from translating the error code into text from the manual.

Does the inverter run up to 50Hz but the motor only turn slowly or is the frequency being limited by the inverter itself and the motor only going as fast as the driving frequency.

A factory reset of the software (RTFM) might be helpful just in case it has been peculiarly programmed for demonstration sometime in its life?

Is it one of these Chinese ones https://www.youtube.com/watch?v=tjhPwYVSSz8

I've got a customer who wants me to use one and I'm dubious at the general lack of support online for them as he want me to buy it and sell on to him which puts all the risk on me. They look too cheap to me.

Bob
Information on induction motors here
https://drive.google.com/file/d/1dBTVXx ... sp=sharing
Email:motors@minchin.org.uk
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Re: VFD extension

Postby wallace » 09 May 2018, 16:38

Yes its very similar to that type. I had another play and it seems to working better albeit a bit glitchy. I went through all of the basic parameters. I put some decent load on the motor pulley by levering a board and it didn't flacker. You can monitor the amps and it was only drawing 1.5, the motor tag says 4.4 and it says the rpm was 1440 at 50hz, the motor is a 900rpm one. Maybe because the vfd is 380v +-15% and the static converter is chucking out 400v.

After messing about with it and getting some progress I've noticed the head bearings are shot so its got to come to bits again, I dont the guy is going to very happy
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