My house is located somewhere with power problems, these have been going on for 15 years and will probably never be fixed. Family lives next door and I want to regulate the power to both my house and theirs with a pure sinus wave power regulator. I was thinking of getting a 15kva/9000W triphase 380V and only use two phases, one for my house and one for theirs.

Our power lines run on 220V. Would this work?! Or do I need to get two single phase 15kva/9000w 220V units.


Unit spec: BRAUN GROUP ES-SVC 15KVA , Triphase

Main Features:

  • Three phase compensation servo motor technology
  • Wide AC input voltage range 276-450V
  • 100% unbalanced loading capability between three phases
  • Digital display for voltage and current
  • Isolated manual bypass switch
  • Full protections such as over voltage, under voltage, overload, overheat, etc
  • Selectable 6s/180s output delay
  • Optional surge/spike protection (replaceable SPD)
  • Optional output isolation transformer
  • Optional RS232/RS485 Typical Applications:

  • Multi-color printing machines

  • Air compressors
  • CNC machines
  • Punching machines
  • Laser cutting machines
  • Welding machines Specifications:

INPUT Rated Input Voltage 380V (400V/415V Optional) InputVoltageRange 276-450V Input Frequency 45-65Hz Power Factor 0.98

OUTPUT Rated Output Voltage 380V (400V/415V Optional) Output Precision ±3% (±1% Optional) Response Time <1s, against 10% variation of input voltage Efficiency over 96%

DIGITAL DISPLAY Input Voltage Line Voltage: AB, BC, CA Phase Voltage: A, B, C Output Voltage Line Voltage: AB, BC, CA Phase Voltage: A, B, C Output Current Phase Current: A, B, C

PROTECTION Output Under Voltage Output cutoff by contactor + "L" in display + Buzzer beeping Output Over Voltage Output cutoff by contactor + "H" in display + Buzzer beeping Overload Output cutoff by contactor + "F" in display + Buzzer beeping Overheat Output cutoff by contactor + "C" in display + Buzzer beeping Phase Failure Output cutoff by contactor + Buzzer beeping Wrong Phase Sequence Can't switch on regulator Short Circuit Input cutoff by air breaker Bypass Isolated Manual Bypass Switch (Automatic Bypass Optional) Output Delay Time 6s/180s Selectable Surge Spike Optional Replaceable SPD RS232/RS485 Optional

SAFETY Insulation Voltage 2,000V / 60s Insulation Resistance >5MΩ Creepage Distance >8mm Grounding Resistance <0.1mΩ Insulation Class of Coil Class F (155?) Cooling Mode Cooling Fan IP Level IP20 Audible Noise

OPERATING CONDITIONS Operating Temperature -5°C - +45°C Operating Humidity 10%-90%, non-condesing Operating Altitude <1,000m

MODEL AVAILABLE: Model No. 15KVA Capacity
15kVA/9kW Machine Size D600 x W520 x H1080 mm N.W.
78kgs Packing Size D610 x W530 x H1200 mm G.W.

  • \$\begingroup\$ Two single phase inverters should be cheaper due to higher utilization. \$\endgroup\$
    – winny
    Commented Jan 31, 2018 at 21:35
  • \$\begingroup\$ It is the other way around, one unit single phase, everyone needs one, cost is 100$ less than a three phase unit. So two single phase units would cost me almost double. \$\endgroup\$
    – unom
    Commented Jan 31, 2018 at 21:55
  • \$\begingroup\$ I don’t know the prices. What I know is passing only two phases of a three phase inverter is 67 % utilization while you paid for 100 %. \$\endgroup\$
    – winny
    Commented Jan 31, 2018 at 22:01
  • 2
    \$\begingroup\$ Is the unit single-phase in or three-phase in? You should also consider just supplying regulated power to the devices that actually need it. \$\endgroup\$
    – Transistor
    Commented Jan 31, 2018 at 23:24
  • 1
    \$\begingroup\$ @unmircea: Have you got 2-phases (of a 3-phase grid) and neutral coming into your house? That would be very strange. If you are thinking of taking a phase from each house I would think you are asking for trouble. \$\endgroup\$
    – Transistor
    Commented Feb 1, 2018 at 10:43

2 Answers 2


For reasons you haven't explained, you seem to have access to two-phases of a three-phase supply. If you power the inverter from this you are effectively running on one phase. One likely problem is that the internal DC bus will probably not hold up well with single-phase supply.

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Figure 1. Three-phase recitification provides low-ripple DC without any smoothing capacitors. Source: if a standard three-phase 400V AC connection is rectified what DC voltage comes out of it?

The single-phase varieties will have large smoothing capacitors built in to hold the DC bus voltage up during the zero-cross.

If you're thinking of adding capacitors to the three-phase unit then you need to be aware that the built-in surge protection to limit the capacitor initial charge current (they look like short-circuits when completely discharged) may be significantly different.

  • \$\begingroup\$ a 3-phase inverter does not typically have a neutral connection, necessary for single-phase applications. \$\endgroup\$
    – Ben
    Commented Jun 18, 2020 at 22:18

Can a triphase current regulator be used with just two phases?

You mean with only two phases loaded on the output? Sure, but if you need to extract the full available power, there may be problems.

100% unbalanced loading capability between three phases

It seems that this particular regulator can shift power between the phases.

But in case it didn't, you'd use a so-called Scott-T transformer arrangement to convert 3 phases into 2 phases, with the load from two phases distributed onto three incoming phases.


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