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Homemade rotary converter 230v single phase to 415v three phase (Video)
tilly819 - 26/7/18 at 06:16 PM

Hi all,
I made myself a rotary converter and am now the proud possessor of 3 phase power at 415v Mwahahahahaha.....

Time to buy all the toys.... now where is my list...

Hope you enjoy.



Cheers.

theconrodkid - 26/7/18 at 06:49 PM

wow!, looks like scarey stuff to me and you have more toys than me

JonBowden - 26/7/18 at 06:57 PM

Another excellent video, thanks

v8kid - 29/7/18 at 11:37 AM

Fantastic video demonstrating diverse skills but why? Static inverters are available from Aliexpress for less than the cost of the components of a rotary converter and have additional features.

Good tip about the hinges and I'll follow your site

Cheers!

tilly819 - 29/7/18 at 12:27 PM

quote:
Originally posted by v8kid
Fantastic video demonstrating diverse skills but why? Static inverters are available from Aliexpress for less than the cost of the components of a rotary converter and have additional features.

Good tip about the hinges and I'll follow your site

Cheers!


Glad you enjoyed it and thanks for subscribing.

To answer your questions>
Most low cost converters only convert at the supply voltage ie 230v single phase in to 230v three phase out. My application required 415v output since my lathe motor will not work on a 230v three phase as it is a 400v-600v motor. Also the coolant pump is 110v which is fed from a 400v to 110v transformer in the lathe.

To buy a semi decent VFD that would meet the requirements of running the lathe with some resemblance of after sales support was around £500 and that would only run the main motor. I would still have to buy a 230v to 110v transformer to power the coolant pump. Now I haven't added it up properly yet but I think my rotary converter has cost me about £350 and that includes the materiel for building the trolley as well.

Finally each three phase motor should have its own VFD as you should not switch the load on and off downstream of a VFD. This would mean I would need 7 VFDs once I have everything setup in my workshop.

TLDR-> For my application it was significantly more cost effective to build the rotary converter.

Thanks

David Jenkins - 29/7/18 at 01:00 PM

You can run a 3-phase 'pilot' motor across the output of an ordinary converter - this will put a load on the converter that will allow the main motor and the cooling pump motor to run either together or independently.

I was going to do this for my big Colchester lathe - I even got the wiring diagram from the converter's manufacturer, Transwave - but never got round to it.

v8kid - 30/7/18 at 10:19 AM

quote:
Originally posted by tilly819
Most low cost converters only convert at the supply voltage ie 230v single phase in to 230v three phase out. My application required 415v output since my lathe motor will not work on a 230v three phase as it is a 400v-600v motor. Also the coolant pump is 110v which is fed from a 400v to 110v transformer in the lathe.

To buy a semi decent VFD that would meet the requirements of running the lathe with some resemblance of after sales support was around £500 and that would only run the main motor. I would still have to buy a 230v to 110v transformer to power the coolant pump. Now I haven't added it up properly yet but I think my rotary converter has cost me about £350 and that includes the materiel for building the trolley as well.

Finally each three phase motor should have its own VFD as you should not switch the load on and off downstream of a VFD. This would mean I would need 7 VFDs once I have everything setup in my workshop.

TLDR-> For my application it was significantly more cost effective to build the rotary converter.

Thanks


Hi tilley,

No these inverters are readily available if you search - I bought a 3 phase 240V to 415V converter from John at Aliexpress here

https://www.aliexpress.com/store/product/VFD-Drives-2-2KW-motor-Input-Voltage-220V-Output-Voltage-380V-frequency-converter-extension-cable-clamp/29491 11_32828152179.html?spm=2114.12010612.0.0.3ca783c5Llnmlv

and it works perfectly for £140 (184USD). It has ramp up and down frequency plus over frequency up to 150hz (IIRC - I still use the gearbox!) and adjustable output voltage with full protection circuitry and links by Ethernet to my PC and has separate front panel or remote (serial) operation or (0-10V ) if you don't like PC control. The only issue with it is that the wiring does not have enough provision for cable glands and I had to bolt on a die cast box to terminate cables in at an extra tenner on eBay.

You are correct that it should not power coolant pumps at the same time but a 230/110V tx is cheap as chips - £40 on the bay for a good one. A lot of people are changing to mist cooling anyhow (idea for a video from you?) so existing pumps may be surplus to requirements

Good point about connecting 7 motors at once and I like the idea of a mobile work table .

Great video on the welding table it has to be my next project all I have to do is "pick up" some 1" thick mild steel sheet.

Cheers

tilly819 - 30/7/18 at 11:06 PM

That's smart bit of kit for £140!

Hmm mist cooling.. I'l have to have a look into that, thanks for the idea .
I think the next video is going to be a new cart for my Tig, my videos at the moment are very much based on 'what I need'. You will probably see quite a dramatically different workshop in the next video as there should be a Bridgeport mill, a high speed chop saw and and possibly a Jones a Shipman 540 arriving in the next week or so. Its like the run up to Christmas here right now...

BTW I only used 1" plate for the table top because that's what I had... Thinner will be fine if you you are not putting loads of heat into the table.

Glad you are enjoying and I really appreciate the feedback thank you