Caribbean Motor Conversion: 220V Three-Phase to 220V Single-Phase

Need to buy a single to three phase converter.

better off getting a single phase motor.

Thanks but should that leg be tied to neutral or ground

sorry, I had initially misread your post and corrected it

But the motor is 220V 3 WIRE

Good post except that neutral is not needed by a 3 phase motor....

The official solution is a 1 phase to 3 phase converter. I would use that in an inspected, official factory installation. First, it is a horsepower sensitive device, so one model is good only for a 1-2kWatt motor. The other - that you most likely thougt about, that much more power is available from a 3 phase connection to the power net, than from a 1 phase. So I assume you need it for a home use / small shop with low Hp machines.

I have good news to you. You are not the first to face this problem. Many machines are available with built-in 3 phase motors cheaply, because nobody want to mechanically fit in a single phase motor.

You get a surplus, higher Hp 3 phase motor, and a small single phase motor. The small one just have to be able to spin up the big one up to speed. You set up a V belt drive between them. That V belt should be tight only when you step on a board to make it so, otherwise loose. You connect the 220V one phase via a switch to the motor, then continue 3 phase thru your shop.

First, you spin up the big one, then you switch on 220V. That way you avoid any big inrush current tripping the breaker. The rotation of the big one works as a rotating transformer, sort of. When you measure it, phase 1 is 100%, phase 2 and 3 is around 60%. Plenty good for a small shop. You just need 50 - 100% larger for the big one to drive all your three phase motors in your shop. Since 3 phase is difficult to get here (except for official industrial use) I know small, production woodwork shops operating this way. I lifted this idea some times ago from www.finehomebuilding.com trade magazine.

What is described above is an "RPC" which is short for Rotary Phase Converter. If you do not want to make your own, you can buy them from a lot of different sources here in the US, but in your country, I have no idea. Here is one source I know of http://www.phaseconverter.com/

Another option is to use a Variable Frequency Drive (VFD). Even if variable speed is not necessary, one side benefit of those devices is that you can feed them with 1 phase power and they will put out 3 phase power. You didn't state the size of your motor, but for most manufacturers, anything up to 3HP (2.2kW) 230V can be done without derating of the drive. Anything larger than that will require derating the VFD by roughly 50% to accommodate the 1 phase to 3 phase conversion. So if you have a 3.7kW motor, you need to buy a VFD rated for 7kW or larger. They may be more expensive than an RPC, but they are MUCH simpler to connect, especially if you don't know much about electrical issues.

I'm sorry, you posted a question about 3 phase 220 v, and then you qualify the three phase by saying the motor has 3 wires?

What am I missing? Single phase motors have 3 wires, and three phase motors have 4 wires.

Which do you have and are you sure this is a three phase motor?

3 phase motors generally have 4 wires - 3 phases and earth, neutral is not needed by most 3 phase motors....a lot of people do not know this!

andy, you do not need 4 wires for a 3 phase motor, the forth wire is for safety reasons only, its a return path for fault currents

You did not understand what I wrote I think, as what you say is EXACTLY what I wrote after some amateurs thought you needed Neutral and I corrected them!!! Speed reading is not quite your Forte I believe!!!

Try and read more carefully, and the posts it was answering before writing in!! here it is again (it was post # 10 I believe if you need to check back....):-

3 phase motors generally have 4 wires - 3 phases and earth, neutral is not needed by most 3 phase motors....a lot of people do not know this!

Ships in the Royal Navy only have an earth bond to the ships Hull, therefore ONLY the 3 phases are needed, 3 core cables only

AMATEURS......thats the nicest thing anybody every said to me,

thanks for the correction

No problem.....been there and done it myself....

You need to tell us the size/wattage/amps of the motor as this will affect the answer!

Also, although you may not have 3 phase in your home, three phases are at least at the local substation, maybe you could have a cable laid if the motor is large, that may be cheaper in the end!!!

I understand Andy,where you are coming from. Relatives in Germany can get 3 phases with no trouble at all. If they opt for an electric storage oven (Speicherofen) they indeed automatically get 3 phase service to the home to cover the energy drawn by it.

In most of the Americas, on the other hand Zoning Regulations prevent it. I got for free some machine tools with 2,5kW or less 3 phase motors. I was happy, and I did not even need the full power of them. I could have lived with a power restriction. City Hall's response: No way, nohow, you are zoned residential. Me: then change that for me. City Hall: we cannot do it just for you, and your neighbours would not agree, as those tax rates are much higher. It did not matter to them, that 200meters down the road are some plant nurseries well supplied with 3 phase power. So much for government logic. So it is do it yourself here, if purchased or cobbled together.

A large portion of the Caribbean has our Code or a version of it.

For just the irony of it, My home get just one phase fom a pole where all 3 are available.

I have never been in a German house that was NOT three phase.....its only a question of cabling and fusing, 35, 50 or 60 amps........thats all.......I re-cabled recently for 60 amps, but I have not had the 60 amp fuses put in as they want €200 to do it!! But I only did it so that if I ever need the extra power, it will be activated in a couple of days......

In the UK, you can pay to have the missing two phases "delivered" so to say.....

But they prevent you Guys from having it? how totally crazy......mind boggling! In a country with only 110 volts for domestic stuff in the first place!! It smacks of 1984!!

I don't know the horsepower of your motor, it may be possible to put a oil filled capacitor in series with one of the wires from your motor to one of the 220 volt lines

you can purchase ar rotory converter for a few dollars in the states ex stock. Although you you require three phase most modern systems have a forth wire which is O (star point) use on m VVF regulators.