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How to get three phases from one

Hello! Today I will show how to get 220 V from a regular single-phase network - a three-phase one, and without any special expenses. But first, I’ll talk about my problem prior to the search for such a solution.
I had a Soviet powerful desktop circular saw (2 kW), which was connected to a three-phase network. My attempts to power it from a single-phase network, as is usually accepted, did not seem possible: there was a strong power drawdown, starting capacitors were warming up, the engine itself was warming up.
Fortunately, in due time I spent the proper time searching for a solution on the Internet. Where I came across one video, where one guy made a kind of splitter using a powerful electric motor. Then he launched this three-phase network along the perimeter of his garage and connected to it all other devices requiring a three-phase voltage. Before starting work, he came to the garage, started the distribution engine, and before leaving he worked. In principle, I liked the solution.
I decided to repeat and make my splitter. In the role of the engine, he took the old Soviet at 3.5 kW of power, with windings turned on by a star.

Scheme


The whole circuit consists of only a few elements: a common power switch, a button for starting, a 100 microfarad capacitor and a powerful motor proper.
How to get three phases from one

How does it work? First, we supply single-phase power to the distribution motor, using the start button we connect the capacitor, thereby starting it. Once the engine has spun to the desired speed, the capacitor can be turned off. Now you can connect the load to the output of the phase splitter, in my case a desktop circular and a few more three-phase loads.
How to get three phases from one

Device body - the frame is made of L-shaped corners, all equipment is fixed on a piece of OSB sheet. Handles for carrying the entire structure have been redone from above, and a three-pin outlet connected to the output.
How to get three phases from one

After connecting the saw through such a device, a significant improvement in work was obtained, nothing is heated, power is quite enough, and not only for the saw. No growls, no buzzing, as it was before.
It is only advisable to take the distribution motor more powerful than consumers by at least 1 kW, then there will be no noticeable special drawdown in power under a sharp load.
Whoever says anything about a not pure sine or it does not give anything, I advise you not to listen to them. The sine of the voltage is clean and broken exactly 120 degrees, as a result, the connected equipment receives high-quality voltage, which is why it does not heat up.
The second half of readers who will speak about the 21st century and the great availability of frequency converters of three-phase voltage can say that my output is several times cheaper, since the old motor is quite simple to find. You can even take unfit for the load, with weak and almost broken bearings.
My idle phase splitter does not consume as much: 200 - 400 W somewhere, the power of the connected tools grows significantly, compared to the usual connection scheme via starting capacitors.
In conclusion, I want to justify my choice of this solution: reliability, incredible simplicity, low costs, high power.

Watch the video


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Comments (18)
  1. Kalle
    #1 Kalle Guests August 18, 2018 01:07
    0
    If there is an excess engine, the idea is normal. But it’s necessary to count on the numbers approximately in the mind. Firstly, if this engine-generator is switched to a triangle, it will be able to give twice as much power (approximately). The connected load (saw) can be about 1 \ 3 of the power of the generator. And if you leave working capacitors in the generator, then 1 \ 2 of the generator power. The idea is good because a three-phase saw can operate at full power. BUT, KNOW THAT IT IS NOT 380 V, but 220 V. The overall efficiency of the system will be reduced due to heat generation by the generator. Previously, your saw with a capacitor circuit could be loaded up to 1 \ 2 of its power (approximately). Previously, it was heated by you because you tried to load it 100%, or did not switch the saw to a triangle and chose the working capacitors incorrectly. Launchers were heated because you chose electrolytic ones.
  2. Guest Alexander
    #2 Guest Alexander Guests August 19, 2018 18:44
    5
    The phrase "Phase splitter ..."))) touched. The electric motor operates in generator mode, more precisely in this case, one winding, phase-shifted. And yet: you can not spend 600 watts and get 2 kW! Or is it a perpetual motion machine, energy from nowhere ???
    1. Mix
      #3 Mix Guests August 20, 2018 12:06
      2
      All is correct. It is a phase splitter. And the engine operates in the asynchronous three-phase generator mode. And 200-600 watts is idling. And under load, the load power is accordingly added. Learn the materiel.
    2. Motarych
      #4 Motarych Guests 10 September 2018 04:47 AM
      1
      And you continue to be touched. every day at work I see. They are installed on electric locomotives. Previously, there was a phase splitter - an asynchronous type electric machine with a generator winding and a relay chopping off the FR at sufficient speeds. On Ermak they put just asynchronous. One terminal is the direct phase from the auxiliary transformer winding. The first half-cycle is taken, the second phase is the negative half-cycle, and the third phase is shifted by the cascade of capacitors. What touched you I generally xs.
    3. Guest Alex
      #5 Guest Alex Guests October 20, 2018 9:59 p.m.
      1
      phase splitter is in the design of the electric locomotive and has been used for 50 years
  3. Ivan Vasiliev
    #6 Ivan Vasiliev Visitors August 20, 2018 01:30
    5
    This is all nonsense. Three phases will not work. Instead of a linear voltage of 380V (phase A, B, C), a phase voltage of 220V (any of the phases and N is zero) is supplied. For rotation of the rotor, this voltage is enough, but it does not start. Therefore, use the usual the impulse of the rotor shaft or a capacitor, which discharges, shifts the existing phase by 120 degrees and thereby briefly becomes the "third" phase. Any electric motor of a three-phase network will not start on two phases or on a phase of N. Yes, and not enough capacitance of a 100uF capacitor for a 3.5 kW engine. Usually, a capacitor of 70 μF is taken for 1 kilowatt of engine power.
    1. Alek
      #7 Alek Guests August 30, 2018 9:37 p.m.
      0
      Theoretically, max phase shift with a capacity of 90 degrees without load.
    2. Motarych
      #8 Motarych Guests September 10, 2018 04:50
      1
      Now go and study the circuit of any AC electric carrier.
  4. Guest Nikolay
    #9 Guest Nikolay Guests August 20, 2018 15:56
    0
    Council, 30 years late in time !!! To get a 3 kW engine, not everyone will succeed, you can buy a new one and make a strange device of it. A new three-phase asynchronous unit costs about 7 thousand rubles, plus other components and materials and as a result a bulky monster. It’s easier to save your time and nerves and buy a device called a power supply unit for three-phase motors from a single-phase network. The device is compact and costs only around 9 thousand. I would choose this option, since the first skin is not worth a mop ...
  5. Vasya
    #10 Vasya Guests August 20, 2018 16:38
    2
    Ivan Vasiliev support Nonsense
  6. Mikhail Ivanov
    #11 Mikhail Ivanov Guests 23 august 2018 13:18
    3
    Complete nonsense. Of course, a 380 volt generator can be made of an induction motor, but certainly not in this way. Judging by the scheme, here the engine works as an autotransformer, and the effect of it will be the same.
  7. Ivan Petrovich
    #12 Ivan Petrovich Guests September 9, 2018 5:04 p.m.
    0
    This method has always been used on AC electric locomotives.
  8. Tagir
    #13 Tagir Guests September 10, 2018 10:05
    0
    Great idea ... sorry I didn't know before ...
  9. Guest Alexander
    #14 Guest Alexander Guests September 24, 2018 16:53
    2
    I’ve been using a normal proven method for 8 years, it’s better to take a low-speed asynchronous phase converter (I read an article in an old Soviet magazine), I have 4 kW * 960 rpm, it starts normally with a capacitor of 120 microfarads, a circular compressor works from it, the compressor , industrial drilling machine, of course, not all together ..
    1. Sektor
      #15 Sektor Guests January 31, 2019 19:57
      0
      Is the city boiler room powered by chance?
  10. ricardo milos
    #16 ricardo milos Guests February 11, 2019 11:56 p.m.
    0
    in the magazine model designer for 1972 №4 there is a splitter circuit on the chokes and a circuit from the patent somehow it came across just working or not xs. And from the asynchronous worker I checked it myself.
  11. Denis
    #17 Denis Guests February 16, 2019 11:38 p.m.
    0
    Hello, I have such a question. There are three sections with separate shields. How to check that the phases are different so that in the end I connected myself to a three-phase machine
  12. Guest Yuri
    #18 Guest Yuri Guests May 27, 2019 13:45
    0
    In my rubbish! Two three-phase are connected in parallel to one phase-shifting capacitor !!! True, the baby, more powerful in its inertia-mass of the rotor, pulls the baby a little. I am embarrassed to even think about the efficiency and load on the network! It is better to choose the working capacity for a specific motor and average load by measuring the current consumption.

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