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two phase from single phase

Discussion in 'Electronic Basics' started by Jon Slaughter, Mar 29, 2007.

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  1. Is it possible to create two phase(or more) from single phase using passive
    components(definitely not any motors) and maybe transistors(or
    semi-conductors)? The design would need to handle large currents and
    voltages so one can't directly use an summing op amp or anything like that.

    Thanks,
    Jon
     
  2. Two phase in what sense? 90 or 180 degrees apart?

    You can run three phase motors from single phase with various devices.
     
  3. Greg Neill

    Greg Neill Guest

    Center tapped transformer for two phases, 180 degrees.
     
  4. ian field

    ian field Guest

    There are plenty of 2-phase motors around, these use a large capacitor to
    drive one of the windings (which is obviously inductive). So it is clearly
    possible to do with only passive components.
     
  5. What I mean by two phase is 90 degree's apart(probably should have said
    that). Also, it does not have to be exact but just approximate(it can depend
    on the load but not to a great extentent).
     
  6. Doable but not for a variable load IIRC.
     
  7. The following circuit will generate 3 phase 144 VAC at 915 Watts output,
    from 122 VAC single phase, at 946 watts input. This is for nearly ideal
    components, and a balanced load. R4 in the circuit must be adjusted to the
    load (R1-R2-R3).

    The voltage across R4 will always be 90 degrees to the input voltage, but
    will vary according to load. If R1-R2-R3 are changed to 1k each, the output
    voltage across R4 will reach 1.7 kV, and the input current will be 48 amps.
    Obviously this will only occur if adequately rated components are used, but
    the phase angle is still 90 degrees to the input. You can adjust the
    resistances to get various outputs.

    I have built a circuit similar to this and it will run a 208/240 VAC three
    phase motor. I used three powerstats and two 120/240 autotransformers.

    It is critical to adjust the inductance and capacitance so they have equal
    reactance at 60 Hz. They form a resonant circuit which must be damped by
    the resistance; otherwise the input current will increase along with the
    output voltage to dangerous levels. I was surprised a couple of times when
    I noticed rather juicy arcs before the input circuit breaker tripped.

    HTH,

    Paul

    ==========================================================
    Version 4
    SHEET 1 880 680
    WIRE 112 128 -144 128
    WIRE 416 128 112 128
    WIRE 608 128 416 128
    WIRE 112 160 112 128
    WIRE 416 160 416 128
    WIRE -144 208 -144 128
    WIRE 608 208 608 128
    WIRE 112 256 112 240
    WIRE 112 256 48 256
    WIRE 416 256 416 224
    WIRE 496 256 416 256
    WIRE 112 288 112 256
    WIRE 224 288 112 288
    WIRE 416 288 416 256
    WIRE 416 288 304 288
    WIRE 608 336 608 288
    WIRE 608 336 272 336
    WIRE -144 368 -144 288
    WIRE 0 368 -144 368
    WIRE 272 368 272 336
    WIRE 272 368 0 368
    WIRE 112 416 112 288
    WIRE 160 416 112 416
    WIRE 272 416 272 368
    WIRE 272 416 240 416
    WIRE 304 416 272 416
    WIRE 416 416 416 288
    WIRE 416 416 384 416
    WIRE 608 416 608 336
    WIRE 0 432 0 368
    WIRE 112 480 112 416
    WIRE 224 480 112 480
    WIRE 416 480 416 416
    WIRE 416 480 304 480
    WIRE 112 560 112 480
    WIRE 144 560 112 560
    WIRE 256 560 224 560
    WIRE 304 560 256 560
    WIRE 416 560 416 480
    WIRE 416 560 384 560
    WIRE 256 608 256 560
    WIRE 496 608 256 608
    WIRE 608 608 608 496
    WIRE 608 608 496 608
    FLAG 0 432 0
    FLAG 48 256 PH-A
    FLAG 496 256 PH-C
    FLAG 496 608 PH-B
    SYMBOL voltage -144 192 R0
    WINDOW 3 -121 130 Left 0
    WINDOW 123 0 0 Left 0
    WINDOW 39 -121 158 Left 0
    SYMATTR InstName V1
    SYMATTR Value SINE(0 180 60 0 0 0 60)
    SYMATTR SpiceLine Rser=.1
    SYMBOL ind 96 144 R0
    SYMATTR InstName L3
    SYMATTR Value 100m
    SYMBOL cap 400 160 R0
    SYMATTR InstName C1
    SYMATTR Value 73µ
    SYMBOL res 128 576 R270
    WINDOW 0 32 56 VTop 0
    WINDOW 3 0 56 VBottom 0
    SYMATTR InstName R1
    SYMATTR Value 68
    SYMBOL res 400 544 R90
    WINDOW 0 0 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName R2
    SYMATTR Value 68
    SYMBOL res 320 464 R90
    WINDOW 0 0 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName R3
    SYMATTR Value 68
    SYMBOL ind2 256 400 R90
    WINDOW 0 5 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName L4
    SYMATTR Value 2
    SYMATTR Type ind
    SYMBOL ind2 400 400 R90
    WINDOW 0 5 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName L5
    SYMATTR Value 2
    SYMATTR Type ind
    SYMBOL ind2 592 192 R0
    SYMATTR InstName L1
    SYMATTR Value 2
    SYMATTR Type ind
    SYMBOL ind2 592 400 R0
    SYMATTR InstName L2
    SYMATTR Value 2
    SYMATTR Type ind
    SYMBOL res 320 272 R90
    WINDOW 0 0 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName R4
    SYMATTR Value 3k
    TEXT -160 392 Left 0 !.tran 500m startup
    TEXT -160 448 Left 0 !K2 L4 L5 1
    TEXT 464 368 Left 0 !K1 L1 L2 1
     
  8. Here is a simpler circuit that produces 208 VAC three phase at over 2 kW
    into three 65 ohm loads. The A-C voltage is at 90 degrees to the input. It
    uses a 3:1 autotransformer (which could be made from a 120:240 transformer.

    Without any transformer, 122 VAC input makes about 71 VAC 3 phase.

    The resistors may be varied to obtain various voltages and phase shifts.

    Paul

    ====================================================================
    Version 4
    SHEET 1 880 680
    WIRE 416 32 256 32
    WIRE 608 32 416 32
    WIRE 560 96 -144 96
    WIRE 608 160 608 32
    WIRE 160 176 112 176
    WIRE 256 176 256 32
    WIRE 256 176 240 176
    WIRE 288 176 256 176
    WIRE 416 176 368 176
    WIRE -144 208 -144 96
    WIRE 112 256 112 176
    WIRE 112 256 48 256
    WIRE 416 256 416 176
    WIRE 496 256 416 256
    WIRE 560 336 560 96
    WIRE 608 336 608 240
    WIRE 608 336 560 336
    WIRE -144 368 -144 288
    WIRE 0 368 -144 368
    WIRE 112 384 112 256
    WIRE 224 384 112 384
    WIRE 416 384 416 256
    WIRE 416 384 304 384
    WIRE 608 416 608 336
    WIRE 0 432 0 368
    WIRE 112 496 112 384
    WIRE 416 512 416 384
    WIRE -144 608 -144 368
    WIRE 112 608 112 576
    WIRE 112 608 -144 608
    WIRE 416 608 416 576
    WIRE 416 608 112 608
    WIRE 608 608 608 496
    WIRE 608 608 416 608
    FLAG 0 432 0
    FLAG 48 256 PH-A
    FLAG 496 256 PH-C
    FLAG 416 32 PH-B
    SYMBOL voltage -144 192 R0
    WINDOW 3 -121 130 Left 0
    WINDOW 123 0 0 Left 0
    WINDOW 39 -121 158 Left 0
    SYMATTR InstName V1
    SYMATTR Value SINE(0 180 60 0 0 0 60)
    SYMATTR SpiceLine Rser=.1
    SYMBOL ind 96 480 R0
    SYMATTR InstName L3
    SYMATTR Value 100m
    SYMBOL cap 400 512 R0
    SYMATTR InstName C1
    SYMATTR Value 70µ
    SYMBOL res 144 192 R270
    WINDOW 0 32 56 VTop 0
    WINDOW 3 0 56 VBottom 0
    SYMATTR InstName R1
    SYMATTR Value 65
    SYMBOL res 384 160 R90
    WINDOW 0 0 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName R2
    SYMATTR Value 65
    SYMBOL ind2 592 144 R0
    SYMATTR InstName L1
    SYMATTR Value 8
    SYMATTR Type ind
    SYMBOL ind2 592 400 R0
    SYMATTR InstName L2
    SYMATTR Value 2
    SYMATTR Type ind
    SYMBOL res 320 368 R90
    WINDOW 0 0 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName R3
    SYMATTR Value 65
    TEXT -160 392 Left 0 !.tran 500m startup
    TEXT 464 368 Left 0 !K1 L1 L2 1
     
  9. An even more efficient circuit puts the loads across the inductor and
    capacitor. It requires an additional autotransformer, but the output
    voltage phase to phase is greater than the input voltage. 120 VAC input
    produces about 140 VAC 3 phase, so 200 to 220 VAC will produce 208 to 240
    VAC three phase output.

    The schematic follows:

    Paul

    ==============================================================================

    Version 4
    SHEET 1 880 680
    WIRE 256 32 -144 32
    WIRE 416 32 256 32
    WIRE 144 112 112 112
    WIRE 256 112 256 32
    WIRE 256 112 224 112
    WIRE 288 112 256 112
    WIRE 416 112 368 112
    WIRE -144 208 -144 32
    WIRE 112 256 112 112
    WIRE 112 256 48 256
    WIRE 416 256 416 112
    WIRE 496 256 416 256
    WIRE -144 368 -144 288
    WIRE 0 368 -144 368
    WIRE 112 384 112 256
    WIRE 224 384 112 384
    WIRE 416 384 416 256
    WIRE 416 384 304 384
    WIRE 0 432 0 368
    WIRE 112 464 112 384
    WIRE 144 464 112 464
    WIRE 256 464 224 464
    WIRE 288 464 256 464
    WIRE 416 464 416 384
    WIRE 416 464 368 464
    WIRE 112 496 112 464
    WIRE 416 512 416 464
    WIRE -144 608 -144 368
    WIRE 112 608 112 576
    WIRE 112 608 -144 608
    WIRE 256 608 256 464
    WIRE 256 608 112 608
    WIRE 288 608 256 608
    WIRE 416 608 416 576
    WIRE 416 608 288 608
    FLAG 0 432 0
    FLAG 48 256 PH-A
    FLAG 496 256 PH-C
    FLAG 288 608 PH-B
    SYMBOL voltage -144 192 R0
    WINDOW 3 -121 130 Left 0
    WINDOW 123 0 0 Left 0
    WINDOW 39 -121 158 Left 0
    SYMATTR Value SINE(0 180 60 0 0 0 60)
    SYMATTR SpiceLine Rser=.1
    SYMATTR InstName V1
    SYMBOL ind 96 480 R0
    SYMATTR InstName L3
    SYMATTR Value 100m
    SYMBOL cap 400 512 R0
    SYMATTR InstName C1
    SYMATTR Value 70µ
    SYMBOL res 128 480 R270
    WINDOW 0 32 56 VTop 0
    WINDOW 3 0 56 VBottom 0
    SYMATTR InstName R1
    SYMATTR Value 69
    SYMBOL res 384 448 R90
    WINDOW 0 0 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName R2
    SYMATTR Value 69
    SYMBOL res 320 368 R90
    WINDOW 0 0 56 VBottom 0
    WINDOW 3 32 56 VTop 0
    SYMATTR InstName R3
    SYMATTR Value 69
    SYMBOL ind2 128 128 R270
    WINDOW 0 32 56 VTop 0
    WINDOW 3 5 56 VBottom 0
    SYMATTR InstName L1
    SYMATTR Value 2
    SYMATTR Type ind
    SYMBOL ind2 272 128 R270
    WINDOW 0 32 56 VTop 0
    WINDOW 3 5 56 VBottom 0
    SYMATTR InstName L2
    SYMATTR Value 2
    SYMATTR Type ind
    TEXT -160 392 Left 0 !.tran 500m startup
    TEXT 440 112 Left 0 !K1 L1 L2 1
    TEXT -96 536 Left 0 ;X(L3) = 37.7 ohms
    TEXT 456 544 Left 0 ;X(C) = 37.7 ohms
     
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