AC power with three legs run 120 degrees out of phase

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29 views

Three Phase Power. Phase Currents to Power and KVA calculations

I'm trying to learn a little bit more about three phase current, power and KVA. We currently have some hi-tech UPS power systems at work and I'm trying to ensure that they are adequately provisioned ...
2
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3answers
78 views

Three phase ground fault

Does a fault in ground of three-phase do more damage to home appliance than a fault in ground of single phase? and why? In a home with three phase input and single phase loads, fault in the ground ...
4
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3answers
66 views

What is proper polyphase AC terminology?

I'm not entirely clear on the proper terminology for polyphase AC systems. I hear it used informally, but I'm not sure what the proper formal names are, if there are any. How I've got it in my head is ...
3
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1answer
45 views

3 phase circuit, 3 x single-phase (hot-hot) loads: what ampacity?

I'm not an electrician (thus the question), but I'd like to know what is possible from a specification standpoint. Let's say we have a standard 3 phase power supply for a commercial building. We want ...
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2answers
73 views

how can i drive a motor with an inverter providing it's power supply? [duplicate]

I'm trying to drive a gyroscope that needs a 3 phase 400Hz 32v 0.7A power supply. i'm going to use an inverter to provide my supply(1phase to 3phase AC: LS-IG5A-0.75kw). i have 2question about it: ...
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1answer
108 views

Making a three phase voltage source to drive a gyroscope

I'm trying to drive a gyroscope that needs a 3 phase 400Hz 32v 1A power supply. How can I provide that supply? It's one part of my university project and I'm a beginner in this field. I'd like to find ...
3
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1answer
57 views

Balanced three phase circuit Y-Y with neutral

Here is my equivalent balanced three phase circuit Y-Y with neutral: Rla + jXla is my line impedance by phase. L1 and L2 are my loads. The exercise is saying that L1 absorbs 180 W and 240 VAr, L2 ...
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1answer
73 views

Disconnectors Symbol in Single Line Diagrams (SLD)

where should the moving part of a disconnector be located when breaking gets applied, on the energized side or on the disconnected side? Is there any standard?? Suppose a non ring, simple grid and ...
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1answer
68 views

3-phase Inverter in single phase operation

I'm working on a standard (AFAIK) 3-phase, 6-pulse inverter. I'm testing it under single-phase conditions to see what the de-rating will be. My understanding: With everything else staying the ...
1
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2answers
105 views

Three-phase rectifier circuit simulation

Is this the correct way to simulate a three-phase full bridge (6 pulses) rectifier? I ask because I have tried this first without the two capacitors, just one, and the capacitor seems to have ...
0
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2answers
90 views

Run a 3 Phase machine, on 240v with start & run capacitors [closed]

Being a Carpenter & Joiner, I must approach "cap in hand" and ask some proper sparkies for assistance in pointing me in the right direction please? Maybe someone could take a look at the wiring ...
0
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1answer
89 views

Use CT current sensor to measure AC current of a single device

So I recently bought 3 current transformers with the goal to measure the current of 3 washing machines. All I want to measure is if the machines are running or not so accuracy isn't really a concern. ...
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2answers
209 views

Is it possible to convert 3 Phase 220V to 110V without use of a transformer?

I am living in an area where line voltage is 220V. If I have access to all 3 phases, is it possible to create a "socket" with output voltage of ~110V, without use of a transformer? This is primarily a ...
1
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1answer
105 views

Help with a full bridge three phase rectifier powered floor

I originally posed a question here asking about solutions to power a small rover 24/7 from a powered floor. It seems the best solution is a full bridge three phase rectifier circuit. I have a few ...
3
votes
3answers
233 views

How is transition from three-phase distribution without neutral to three-phase consumption with neutral achieved?

A typical distribution grid supplies 6 or 10 kilovolts AC to a substation near the consumers. This is typically done with a three-phase line without neutral - just three wires going in parallel. Then ...
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0answers
40 views

Rotation-switched active rectifier idea

Most of you will know how three-phase rectification works and how cool it is. My idea is: replacing the diodes in a three-phase full-wave diode bridge with MOSFETs, as in active rectification, and ...
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4answers
293 views

Three phase power supply - what is line to line voltage

Well this seems like a basic principle, yet I can't seem to get it. (We're expect to "know" this already). In a three phase situation I'm given a source voltage of 230V. - So the waveform of each of ...
3
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1answer
106 views

What determines what type of short-circuit current is highest?

I'm doing a short-circuit analysis of a system, and started wondering about the following: What determines which type of fault current is the highest (and lowest)? The screenshot below shows the ...
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2answers
72 views

Powering Several Electrical Components from Single Three-Phase 240V AC Supply

A system consisting of various electrical components is desired. Required supply voltages to power these components include the following: three-phase 240 V AC (directly through the supply), 24 V DC, ...
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3answers
138 views

Finding frequency of a three-phase generator from phase voltages

I'm trying to find frequency (i.e.; rotations per second) of a balanced three phase generator. Output peak voltage of the generator goes up to 150V. One solution I found is to attenuate rectified and ...
1
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0answers
94 views

Missing phase 3-quadrant TRIAC-based solid state relay for 3-phase engine

First of all, I'm a simple mechatronics technician student first time posting here, so please don't mind if I say something that seems completely stupid, since I consider myself to be a total newbie ...
4
votes
2answers
306 views

Three phase rms voltage calculation

I am new in instrumentation and control. I am developing a hardware for a project and the following is my application. I have three phase stepped down voltages and stepped down currents entering my ...
2
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3answers
345 views

Three phase heaters and amps

I am a mechanical engineer with basic understanding of electricity. I am programming an app for ordering 3 phase heaters, and I have an argument to resolve with a coworker. Lets say I have a 208V ...
1
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1answer
106 views

Obtaining three different DC voltages from a three-phase AC supply

I have three identical sinusoidal voltages, R, S and T, whose phases are spaced by 120o difference. I want to obtain three different DC (unfiltered) voltages from these tree AC signals for some ...
2
votes
3answers
214 views

Calculating phase currents and neutral phase current

I am doing a homework that I got yesterday and it concerns calculating phase currents and a neutral phase current. 3 phase it is. Three individual charges, each on their own phase and a shared 3-phase ...
4
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4answers
226 views

Control torque of 3-phase AC motors

Actually, we have 1x30HP, 2x10HP motors working at our workplace. When we start the motors there is a lot of torque generated due to which our grid supply charges us penalty every month. We need ...
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0answers
62 views

Capacitor motor vs. three phase motor

I successfully converted a small (~15W) capacitor driven one phase synchronous motor to a three phase motor by removing the capacitor and connecting the two windings to a three phase motor frequency ...
2
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1answer
130 views

Is there a rectifier scheme for tri-phase which is more efficient than the bridge rectifier?

Because of the topology of tri-phase bridge rectifier, every phase is active (i.e.; feeding the load) only for 33% of the time. It feels like we are not fully utilizing all the three phases, and ...
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1answer
117 views

Three Phase to single phase [closed]

I have 1Kw supply of three phase in my home. I need a single output of all three phase and neutral. E.g If I connect 1 equipment of 600watt 15 amp single phase, now I want equal load 200watt 5 amp on ...
4
votes
1answer
101 views

Obtaining DC from a tri-phase generator

I have a tri-phase generator which outputs AC voltage waveforms (\$R\$, \$S\$ and \$T\$) with 120o phase shift between them. I want to rectify these voltages and obtain a single DC voltage. I ...
3
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2answers
377 views

General 3 Phase Motor Inductance Question

I know that motors are inductive loads. Does the inductance of a 3 phase motor depend on the load on the motor?
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1answer
69 views

Can a 3-phase rectifier handle input from a 1-phase/2-phase source?

In trying to homebrew a miniature wind-turbine using the stepper out of the tray motor from the CD Drive (sloth that I am) I'm loath to go to the effort of constructing a rectifier, and a regulator. ...
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3answers
2k views

difference between single double and three phase

If single phase is 230 V and 3 phase is 440 v then what about for 2 phase? And why is it so?
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0answers
53 views

Faulted phase detection

Currently I am studying about short circuit detection on long lines and I can't solve one task: I have line between two substations, and there is short circuit some where on this line. I know current ...
0
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1answer
64 views

Any Ideas for Understand one of the 3 phases has powered

I want to ask you about a situation which i couldnt find the exact solution or better way to do the job. The situation is i have 3 phase (380V) induction motor and one of the phases to the motor had a ...
2
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0answers
224 views

How calculate three phase kilowatt hour from time sampled data of voltage and current of each phase

My problem is I want to calculate three phase kilo watt hour from time sampled data of current and voltages. My doubts 1) How can I calculate the kilowatt hour from time sampled data? Is it any ...
3
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2answers
289 views

Do I have pseudo three-phase power at home?

I get three live wires and one neutral from the mains. Different rooms in the house are connected to different circuits which terminate at a changeover panel. The changeover switches allow each ...
0
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1answer
589 views

Why is using a single phase device across phases of a 3 phase outlet OK?

My friend connected two wires to two "non-earth hole" in a 3 phase outlet (208V) to run a 220V single phase blower (Note: the outlet has four holes, one of them is earth). Basically, he used the ...
0
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1answer
216 views

Ground Fault Question Regarding a 3 Phase Circuit

I'm needing to design a 3 phase ground fault detection system for a 480V system. It will need to be able to trip when there's ground fault current >1A. I have done some reading and it sounds like ...
3
votes
1answer
2k views

Why does a 240 volt outlet save money in electrical cost than a 120 volt outlet?

I live in the US and we have many outlets that run at 120 Volts. I heard that for devices that support the 240 volt standard may not cost as much in electricity prices. Can someone explain how by ...
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1answer
789 views

3-phase power calculation when phase to phase voltages are different

I have a 3-phase power supply rated at 230VAC per phase. However, the phase to phase voltages are not equal. Suppose \$V_{RY}\$, \$V_{YB}\$ and \$V_{BR}\$ be the three phase-to-phase voltages between ...
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1answer
125 views

Terminals of three phase power machine

A three phase machine, instead of having six terminals, two for each slip ring, has only four terminals. Because the starting point of all the three coils have a common junction which is usually ...
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1answer
269 views

How to measure phase angle of 3 phase by microcontroller

I am currently using PIC18F452, trying to measure the phase angle of 3 phase. How can I measure this. What feature of PIC can I use to solve it.
0
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1answer
53 views

Searching for phase change device

Anyone knowing of a module that can monitor three incoming electrical phases to a home. If the load goes over a certain maximum, the device changes to one of the other phases for supply to e.g ...
0
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3answers
400 views

drive 3 phase induction motor with only DC (not pwm) thru each phase

I've been researching making a driver for a 3 phase induction motor powered by DC source using PWM to approximate sine waves in each phase. However, the switching speeds of the PWM signal for the ...
5
votes
6answers
715 views

Determining phase sequence in software

We have 3-phase electric network. How to determine phase sequence (L123 or L132) from 2 line-to-line voltages U12 and U32? I prefer computationally simple solutions. Is it possible to determine phase ...
2
votes
1answer
264 views

3 phase induction motor with one phase [duplicate]

Possible Duplicate: 2 Phase to 3 Phase conversion Is there a way to run a 3ph induction motor with one phase . Basically I have 3ph motor but my power supply is only 2 phase . Is there ...
6
votes
3answers
4k views

Single-phase to 3-phase conversion

I have seen some boxes (with some capacitor circuits inside) which do single-phase power supply to 3-phase power supply conversion. The problem with them is that they cause the load motor to heat up, ...
2
votes
1answer
258 views

IC for converting single phase to three phase

I want to design a device for use and control three phase ac motor with single AC power. I need to able converting single phase to three phase. Also an three phase ac motor controller should be ...
4
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4answers
384 views

3 phase computer chip

I have just had a conversation with a friend who studied quantum computing. Sadly I have forgotten most of the conversation as it was far beyond my knowledge threshold. Essentially he was saying was ...