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Single phase to 3 phase converter

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ahz

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does anyone have any idea or know about a high power single phase to 3 phase converter . the problem is that we have a 3 phase motor about 3 kw but our electrical source is single phase ?
my own idea is to design something like the scott connection .

thanks in advance

Ali
 

flatulent

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Very complex

I suspect that it is very difficult. One conceptual way is to have three transformers across your single phase line. Two of them have series capacitors or inductors on the primary side to make the 120 degree phase shifts. These shifts will be a function of the motor load and therefore not exact. The transformer outputs are then placed in the delta or Y connection.

A possibly better way to get the 120 degree phase shifts is with low pass and high pass filters on the input. The cutoffs will be outside the line frequency.

The element rating should be very high. The motor would draw 1 kVA from each transformer which is 5 A at 200 V.
 

octron

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Have a look at the german site

h**p://www.e-plan.josefscholz.de/page6.html

The circuit is called "Steinmetzschaltung"
 

sat30

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A simple way to solve your problem is to connect neutral and phase of your single phase ac line to two of the three wire of motor, and a non polarized capacitor between the other wire of the motor and the phase of your ac power source. A capacitor of 100 micro farad can be useful to start motor. The only think that leave me some doubt is the high power of the motor (3 Kw), but you can try, eventually raise up the capacitor (you can connect more capacitor in parallel)...
Think about the volt of motor and the tipology of connectio (star - triangle) ; if it is 380V and you connect it to 220Vac you have less power from it..
 

hobbymat

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You can use a VFD (variable frequency drive) to drive the motor. There are also VFDs that are designed to take in normal 1-phase electricity and give out three phases with the same voltage than input and a typical frequency of 0...110 Hz, adjustable via a potentiometer and/or the drive's control panel. Just connect the three-phase motor from Y to Delta to get the required voltage to the correct level (e.g. 380 -> 220 volts).

You can also drive a bigger, three-phase VFD with one phase only, but you'll have to de-rate the power output by about 60%.

I love VFD's, to me they are a must in a lathe, pillar drill, milling machine etc. and they are commonly available nowadays with an affodrable price.


Hobbie
 

flatulent

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link above

The link above shows a way that may work if your motor is not loaded very much mechanically. It is inefficient and may overheat your motor, so monitor the temperature for a while.
 

netboy

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ahz said:
does anyone have any idea or know about a high power single phase to 3 phase converter . the problem is that we have a 3 phase motor about 3 kw but our electrical source is single phase ?
my own idea is to design something like the scott connection .

thanks in advance

Ali
Hi
I don´t test it with 3KW, but abaout 1KW
try connection in delta:

Phase R in U - Z N in W- Y
and the capacitor in V - X
the capacitor with 450v and about 200uf
To invert rotaction you can change N in W for N in V
 

avinashr

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1to3 phase converter

pl check out a project article was published in elektor electronics late in 1990s "single phase to 3 phase converter"
8)
 

artem

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Hi

May be it is stupid, but there are three phase to one phase transformers. If its output will be supplied as input , you should get 3 phase output on transformer input . The transformation must work in both way .

I did use the capasitor to get thrid phase motor working but as you have to use 180 degree phased voltage on 2 input , there could be problem with losses in motor , thus lead to heat and efficiency decline especially when motor is about 3 KW .
 

embuh_ah_bingung

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i searching paper about " Modified multiple pwm for induction motor speed control using microcontroller atmel" can any one give help. thanks
 

machinejill

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I ran across this great site on the web www.phaseconverter.com these guys seem to know there stuff, pricing looks good, give them a call they should be able to help you out.
 

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