AC power with three legs run 120 degrees out of phase

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1answer
86 views

How does 3 phase power operate single loads?

I am wondering how 3 phase power is used to power, say for example, light bulbs? If I have 3 phase power coming into my house, how are the 3 phase combines to enter the one prong of an electrical ...
0
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1answer
56 views

Three phase transformer windings

I have a quick question about three phase transformer windings. if I have a transformer that is Yd11 but I connect the generator to the d-side instead(primary side). Does it become Dy11 connected or ...
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4answers
165 views

Why do we need 3 phase power supply?

Why do we need 3 phase? For the reason that voltage will never be zero in 3 phase? OR we need high voltage?
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0answers
27 views

3-phase BLDC motor operation

I salvage motor from HDD, then I started googling around how to make it spin and found this video(there are good subtitles in English): https://www.youtube.com/watch?v=CMz2DYpos8w Here he just plug ...
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1answer
66 views

How does a multimeter sense whether it is measuring single or 3 phase voltages?

How does a multimeter sense whether the voltage we are measuring is single phase or three phase? It might be simple but I have no idea so please help me.
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2answers
90 views

Electric company supply single-phase or 3-phase?

Does the electrical company generally only supply single-phase in residential areas? i.e.: is 3-phase generally only available in higher use areas? And when 3-phase is supplied, do they have separate ...
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1answer
41 views

Field oriented control motor controller: is the measured Iq rms or the peak current? [closed]

Say the regulator regulates Iq to be 1A, is the actual motor current 1A RMS or 1A/sqrt(2)=0.707A?
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1answer
48 views

Three phase motor current verification

I want to verify that the quadrature current through a permanent magnet synchronous motor (PMSM) is actually the same amount as I commanded the field-oriented control (FOC) motor controller to push it ...
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1answer
47 views

Running single-phase through two or three windings of a three-phase inductor; why does the direction of the middle winding matter?

I have a three-phase inductor, MTE RL-00403, nominal 9 mH. I have some experimental results that don't make sense to me, which appear to be related to the fact that all three chokes share a single ...
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1answer
62 views

How to know if questions in an exam mean line, phase, or RMS voltage?

What is the difference between line, phase and RMS voltage? We get many questions where it is not mentioned whether the question is specifying line, phase or RMS voltage. I will attach some example ...
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6answers
2k views

Why are there only 3 wires on this power line?

When I was in Alaska, I saw a high voltage line, but I didn't see the Neutral. Is this because the water is conductive enough next to it to use as neutral? Or is it just two Phases. Where I ...
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1answer
67 views

motor Back EMF phase differences

I am reading though a product manual for an amplifier that I am working with. It says that if you view the motor Back-EMF while it is disconnected from the controller and spun in a clockwise direction ...
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0answers
81 views

Calculating Voltages in phases when a neutral fails

In the above star-connected three phase circuit the neutral is floating. I need to find the voltage across each load and which voltages are higher than 240 (Assuming the Line-to-line voltages are ...
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1answer
47 views

Calculating phase angles from symmetrical components

I'm getting the following values from a meter: ...
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0answers
57 views

How to add a desirable phase shift in the input from 3-phase ac mains?

I want to build a 12 pulse rectifier circuit. I know delta-wye or wye-delta transformers can be used to add phase shifts equal to the multiples of 30, but I don't want to use transformers. Is there ...
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3answers
188 views

Single phase from 3 phase generator

I got a good deal on a 3-phase generator, but everything I have is single phase. There's a sticker on it that says 230v 60hz. The output is a 4-wire plug. I did some testing with my multimeter and it ...
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3answers
77 views

Emergency 3-phase power supply in the event of power failure

I have two Magnum 400 10/20 drivers running two stepper motors. Peak power consumption is about 2 kW. In the event of a power failure on the 3-phase supply, I'd like to trigger a controlled emergency ...
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1answer
292 views

Calculate total apparent, average and reactive power in 3-phase

I am given a balanced 3 phase circuit question shown in the linked image. I am confused on the difference between apparent, average and reactive power and how each is calculated. This is my first post ...
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1answer
198 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 ...
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3answers
788 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 ...
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3answers
94 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
259 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
93 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
134 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
95 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
138 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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2answers
118 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 ...
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2answers
222 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 ...
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2answers
991 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
239 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
1k 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
128 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 ...
4
votes
3answers
2k 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
49 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
4k 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
216 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
131 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
221 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 ...
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0answers
133 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
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2answers
528 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
2k 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
149 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 ...
3
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3answers
2k 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
424 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 ...
2
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1answer
193 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
190 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
112 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 ...
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2answers
771 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
84 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
7k 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?