Phase Converter question - 1ph to 3ph

[ExpatIreland]

I am in Ireland (230 v / 50 Hz). At my home shop I have single phase power. I'm buying a large coffee grinding machine with a 5.5 kW (7.5 hp), 3 phase motor . So obviously I need a phase converter. I am looking at a 7.5 kW rotary phase converter with a motor start capacity of 5.5 kW. Before I invest £8,000 in the converter and machine can you give me any tips on the best type of phase converter to buy and any questions I should be asking the manufacturer of both the machine and phase converter?

Also I am purchasing a weigh and fill machine for coffee bags from the U.S. It is standard 110 V / 60 Hz power. The motors on this machine are small, like 1/2 hp to run a small belt drive and a small air compressor. I have a 1 ph converter here in Ireland that is Input 230V / 50Hz and Output 110V / 50 Hz. Should I use this converter? Or should I put a frequency converter in-line that takes the power from 50 Hz to 60 Hz? Or should I buy 1 converter that is input 230V / 50Hz and Output 110V / 60 Hz?

Thanks in advance for your help and suggestions!

 

[zlatkodo]

Some additional explanation about mentioned above:
The best outcome is if the three-phase motor is designed to work in Wye-connection .
If three-phase motor is designed to work at Y 400 V, then need to be reconnected to delta and connected to single-phase supply 230 V (in Steinmetz -connection).
Or, PHASE voltage of three-phase motor should be equal to voltage of single-phase supply.

Also, there are some other options for single-phase use of three-phase motors ( "star" or so called "broken star" connection) but with some limitations regarding the voltage ratio.

 

[waross]

Hi zlatkodo. Can you describe the "Broken star" connection for us.
Thanks

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[zlatkodo]

Hi, waross,
Here you can find some of options.

 

[ScottyUK]

I've never seen the 'broken star' (bottom centre) connection before. Does it work, and if so how well does it perform when compared to the more conventional connections?

 

[waross]

Thanks for the information zlatkodo.
It's good to learn something new.
It is interesting to see the diagrams with switched capacitors. I assume that that is to improve the starting torque?
I wonder, looking at the top left and top center diagrams, will these motors turn in opposite directions?
The broken wye connection would not normally be used with NEMA motors with the buried wye point, or, in the case of the occasionally seen delta connected motors NEMA, three buried delta corner connections.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ExpatIreland]

I've been away and very busy roasting coffee. We drink all we can and sell the rest . I want to thank every one for their input. Much appreciated!