AC power with three legs run 120 degrees out of phase

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48 views

Need to connect neutral wire?

In 3 phase machines have L1,L2,L3,N and PE(Protective earth).some time Neutral wire is not connected to the power supply.But,Machine have a neutral wire.What will happen if not connect neutral ...
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0answers
38 views

Wiring diagram and phase number of three phase transformer

Does anybody have an idea how to draw vector diagram of primary and secondary of a three phase transformer? For instance, if I need to draw vector diagram for Yzn5 diagram and then also draw the ...
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1answer
76 views

What happens if we run 415V 3 phase motor running on full load on to a 240V 3 phase supply?

I have a 415V 3 phase motor, but during emergency situation a 110V DC to 220VAC 3 Phase inverter comes into place. What will be the effects on the motor
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1answer
30 views

Single-Phase to Three Phase Cycloconverter

When my classmate report about cycloconverters. He discussed about different classifications and types of cycloconverters. He also discussed how Single-phase to Single-Phase Cycloconverters operate. ...
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1answer
82 views

Calculating single phase load from 3 phase power measurements

I need to record kW & kWh for individual phases on a circuit that has a 3 phase power meter that outputs the following data: Total for all three phases: kW kWh kVA kVAr power factor ...
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1answer
24 views

Mitigate the effects of magnetic induction heating in a three phase AC system

To mitigate the effects of magnetic induction heating in a three phase AC system, it is common practice to group the conductors and to keep them in the same raceway. Also, three phase power is ...
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2answers
98 views

Obtaining 240V from 480V 3-phase

We have a 480V 3-phase connection for a borehole pump, and we need to get a temporary 240V connection for lighting, no more than a few hundred watts. We are in South Africa which operates at 240V, ...
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0answers
59 views

Calculation of line-to-ground voltages from line-to-line voltages

I'm studying Electrical Engineering with the specification on Energy and Drive Systems in Germany. I currently have a task to develop a program, which gets some three-phase Voltages (line-to-line ...
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3answers
416 views

Y or Delta connections advantages / disadvantages

I have been studying three-phase systems for the whole course of a subject (on the first year of the university degree). I have finished now, and I know both "Y" (star) or "Delta" (triangle) ...
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1answer
80 views

Why would someone use an amplitude modulation ratio lower than one in a power inverter?

We had a test the other day, and there was this question: What is the minimum DC voltage required to drive a PWM, half-bridge, three-phase, power inverter to 4160Vrms. It should be possible to vary ...
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1answer
59 views

Three-phase system question

I'm solving some problems on three-phase systems. I'm doing pretty OK, but there is one problem that I'm not sure about the answer so I have some questions. We have a three-phase circuit connected in ...
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0answers
57 views

Three phase transformer question ?

we both agreed on the value of series impedance which is (12.82[82] ) however what i think he did wrong is the value of secondary reflected on primary since it is Y-delta 7967/480 = root(3) a ...
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30 views

Is it like that we can generate power in multiples of 3 only like ( 3 phase , 6 phase ) and can't generate in numbers llike 4 phase ,5 phase ? [duplicate]

does it has something related to symmtery ? Also why we prefer 3 phase more than others ?
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35 views

Three Phase Transformer

(Sorry for the bad drawing)... The picture contains three single phase transformers connected in star(both H.V. and L.V. sides). Now if i connect a load between the phase 'c' and 'n' keeping the ...
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1answer
145 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 ...
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1answer
84 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
385 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
43 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
87 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
210 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
60 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
59 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 ...
0
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1answer
65 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
93 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
3k 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
96 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
113 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
54 views

Calculating phase angles from symmetrical components

I'm getting the following values from a meter: ...
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0answers
65 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
622 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
86 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
821 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 ...
0
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1answer
304 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
1k 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
115 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
432 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
108 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
145 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
121 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 ...
2
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1answer
168 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
131 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
327 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
2k 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
299 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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3answers
2k 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 ...
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1answer
138 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
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3answers
3k 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
50 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
9k 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
336 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 ...