Rotary Phase Converter (Create 3-phase power from a single phase source)

[Frank S]

They are downloading now but I should have waited until I had a lower internet usage going on LOL

[smithdoor]

This is three-phase to two-phase transform
I have only seen this in books and was uses around 1900
I was told by a old electrician is use for 115 volts for offices and last time he ever saw was in build built in the 1920's

Dave

[nhengineer]

Rhengieer,
I thank you for your effort, but now you see what I mean when I say, in Australia most of the options to date are totally uneconomic, for instance, I need to power a 3 phase mig welder which is name-plated at 10 amps per phase which is about 7.1kw at 230 volts. If a 3hp transformer is likely to cost $450 US that's around $600 AU, and I might need two...$1200 plus freight, and as I mentioned before freight from the US to AU needs the surrender of ones first born, I would not be surprised to find that the freight exceeded the initial cost of the transformers. Also 3hp would woefully inadequate, I need at least 10 amps per phase, for a overload margin, maybe more.
So at a potential cost in excess of $2400, a second hand 3 phase generator is starting to look a lot more realistic.
I thank you for all your effort, and indeed to all the other contributors to this thread, but unless I can find a way to control a synchronous motor acting as a generator, I have two options:- buy a generator or attempt to rewire the welder to run on single phase. Incidentally, I'm informed by the manufacturers of the welder, that the configuration internally is actually three separate transformers feeding a bank of full wave bridges, so it could be possible.
If anyone is interested I'll keep you informed.

Rob.

Rob,

Are there no transformer manufacturers in Australia?

David Lee
(NHEngineer)

[nhengineer]

This is three-phase to two-phase transform
I have only seen this in books and was uses around 1900
I was told by a old electrician is use for 115 volts for offices and last time he ever saw was in build built in the 1920's

Dave

Why would anyone want to go from 3-phase to 2-phase?

[nhengineer]

How are using this transformer
I was thinking this for single to three phase
Most motors that are 415 volt can also be wire 240 they wye/delta wound motors
I think take close look at the motor to see what type it is most wye delta motor are 6 wire type

Dave

I think I'll make a 2-phase DC alternator.

[Frank S]

Rob,

Are there no transformer manufacturers in Australia?

David Lee
(NHEngineer)

David I know of 2 or 3 guys who make their own transformers 1 lives on Flinders Island Au another over in NewZeeland Not sure wher the other guy lives but I have used his online calculator to make several small buck & boost and step down transformers. He goes by the username of Josetue the link to his spreadsheet is on his post on this page about halfway down
From New SMA INVERTER SI6.OH-11, battery full 50HZ Jumps to 60Hz
OZtules is a foremost authority on building power inverters and just about any other off grid power generation His 6KW pure sine inverters have been made by several. I'm not sure about their 3 ph activity though but their published information is well worth having a look at
Here is a link to Joestue's spreadsheets
Index of /bulk/spreadsheets
I downloaded your RPC plans and had a look at them You used a different approach than what I have, but very informative and well written thanks When I build my next 8hp RPC I can see incorporating your plans with the way my current RPC is made because I like having the capacitors to balance out the ph shift

[smithdoor]

FYI
I have made my own transform a long time ago. The hard part is find a core the low cost way was to build a TOROID type and use gal electric fence wire simple to wind into a dough shape. The in recent I used is microwave transform core

In some parts of world they use a bank of capacitors for AC 3 phase when they only have single phase power. But only works when have the same load on the motor. This not work for machine tool or air compressor as the load changes.

At one time in life look into or try ever way as shop only had single phase. I finally landed on four ways

1) change the motor
2) rotary converter
3) static converter
4) motor generator

I did at time have over 20 employs working for me manufacturing aircraft hangar doors

Dave

David I know of 2 or 3 guys who make their own transformers 1 lives on Flinders Island Au another over in NewZeeland Not sure wher the other guy lives but I have used his online calculator to make several small buck & boost and step down transformers. He goes by the username of Josetue the link to his spreadsheet is on his post on this page about halfway down
From New SMA INVERTER SI6.OH-11, battery full 50HZ Jumps to 60Hz
OZtules is a foremost authority on building power inverters and just about any other off grid power generation His 6KW pure sine inverters have been made by several. I'm not sure about their 3 ph activity though but their published information is well worth having a look at
Here is a link to Joestue's spreadsheets
Index of /bulk/spreadsheets
I downloaded your RPC plans and had a look at them You used a different approach than what I have, but very informative and well written thanks When I build my next 8hp RPC I can see incorporating your plans with the way my current RPC is made because I like having the capacitors to balance out the ph shift

[nhengineer]

David I know of 2 or 3 guys who make their own transformers 1 lives on Flinders Island Au another over in NewZeeland Not sure wher the other guy lives but I have used his online calculator to make several small buck & boost and step down transformers. He goes by the username of Josetue the link to his spreadsheet is on his post on this page about halfway down
From New SMA INVERTER SI6.OH-11, battery full 50HZ Jumps to 60Hz

Do you mean you boys down there need to import things like this? Crikie! I could come down there, open up a shop and get rich!

OZtules is a foremost authority on building power inverters and just about any other off grid power generation His 6KW pure sine inverters have been made by several. I'm not sure about their 3 ph activity though but their published information is well worth having a look at. Here is a link to Joestue's spreadsheets
Index of /bulk/spreadsheets

You don't need a 3-phase transformer. Single phase boost transformer ANSI schematic below:

Sorry, I've not yet been able to finger out those ISO symbols.

The output section is configured so that there is a 180° phase shift from one output to the other. That will give you two 230V outputs a half phase apart. That is what we have for residential high voltage here in the USA (except it's 240-250V). With that you can use that at the input to my design and create (kind of) a 230V 3-phase suitable to run your 230V, 3-phase motors with reduced horsepower output (83.3% of the nameplate rating)

I downloaded your RPC plans and had a look at them You used a different approach than what I have, but very informative and well written thanks When I build my next 8hp RPC I can see incorporating your plans with the way my current RPC is made because I like having the capacitors to balance out the ph shift

Thank you for the compliment.

[old kodger]

Rhengineer,
You possibly could come down here and get rich,........provided you're prepared to import a shipping container full at a time, it's the freight that kills us. If I buy a Briggs and Stratton engine here, it'll cost me $100 per hp, I used to run a business mowing grass, and at the time a 20hp engine was $2000 plus gst (10%) when the US price for the same engine was $400 plus freight, but it still meant that I could land it here for around $1000.
The answer to the question of do we have to import this stuff...yup! because the local cost is even greater.

Rob.

[smithdoor]

FYI
back 2002 for a shipping container 40' long [12.2 meters long] From the USA to part of work cost FOB dock $6,000.00 Plus $500.00 from my shop to the dock.

Dave

Rhengineer,
You possibly could come down here and get rich,........provided you're prepared to import a shipping container full at a time, it's the freight that kills us. If I buy a Briggs and Stratton engine here, it'll cost me $100 per hp, I used to run a business mowing grass, and at the time a 20hp engine was $2000 plus gst (10%) when the US price for the same engine was $400 plus freight, but it still meant that I could land it here for around $1000.
The answer to the question of do we have to import this stuff...yup! because the local cost is even greater.

Rob.