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
Two phase in what sense? 90 or 180 degrees apart?
You can run three phase motors from single phase with various devices.
Center tapped transformer for two phases, 180 degrees.
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.
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).
Doable but not for a variable load IIRC.
"Jon Slaughter" wrote in message news:8lWOh.3910$ snipped-for-privacy@newssvr21.news.prodigy.net...
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
"Paul E. Schoen" wrote in message news:460c976b$0$30081$ snipped-for-privacy@news.coretel.net...
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
"Paul E. Schoen" wrote in message news:460cab66$0$30081$ snipped-for-privacy@news.coretel.net...
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
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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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