AC power with three legs run 120 degrees out of phase

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19 views

symmetrical components and power conservation?

My understanding of the method of symmetrical components is the following: An unbalanced three phase system (voltages, currents etc.) is split into three balanced sets; zero, positive and negative ...
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2answers
45 views

Using Single-Phase and 3-Phase Equipment?

Let's say I have a single-phase facility and I plug in a piece of 3-phase equipment, what happens? Is it dangerous? Is it less efficient (if so, approximately how many percent less in efficiency)? ...
1
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1answer
29 views

Three phase balanced transformer network with b-phase fault

100 kVA, 11 kV (delta) : 400 V (wye), Xeq = 0.1 p.u with a neutral to ground connected through Zn = j0.1 (ohm) I have a question where the above transformer is fed by a balanced positive sequence ...
34
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10answers
7k views

Why three-phase power? Why not a higher number of phases?

Is there a reason, beyond historical reasons, that three phases has become the dominant number of phases? I am aware of the advantages against one phase and two phase, namely the reduced amount of ...
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2answers
87 views

How to wire three phases for 220V?

In Thailand we usually use 3 phases (L1, L2, L3) + Neutral (N) + Ground (PE) with 220V. A machine imported from Taiwan has four connectors: L1, L2, L3 and Ground (connected to the housing). It uses ...
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3answers
88 views

How to change rotation direction of 3-phase electrical machines?

I was taught that if you want to change the direction of a three phase rotating machine that is rotating in forward direction, you interchange the phases. Since the phases has the same features ...
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0answers
30 views

delta-star three-phase transformer for single phase

Can a delta-star three-phase transformer be used with a single-phase supply and load without damaging it? simulate this circuit – Schematic created using CircuitLab Primary: star/wye ...
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1answer
50 views

Question about output current

I've got huge three-phase transformer, primaries are connected in Y configuration, secondaries in Delta, then goes to 6 diode bridge rectifier. Output is about 200 amp 52 VDC. In short, how many ohm ...
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1answer
74 views

Phase Sequencer

I have 3 phase voltages entering into my PIC ADC (3 different channels ) through a voltage down scaling circuit and I have successfully calculated their rms values inside my controller.Know I want to ...
3
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2answers
89 views

What's a good set of PWM values to make sine waves for a 3 phase motor?

I'm building a synchronous rotating spark gap for a tesla coil. I have a working mcu (Kinetis K64F) driving a 230volt inverter board and it spins a 3 phase synchronous motor. The motor is a ...
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2answers
57 views

Calculate a voltage angle offset for a 3-Phase utility meter

I'm trying to analyze and write a program around some data that I was given. The data is a collection of readings from 3 Phase smart meters of an electrical utility. One value in the data that I can ...
2
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2answers
111 views

Will a RCBO 4P trip in case of neutral fault/failure/interrupt/float?

We have 3 phase power supply in my home which is used to power single phase 240V 50 hz appliances with common neutral. (Diagram in the link at the bottom) The only protection we have as of now are ...
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1answer
72 views

Question regarding a resistor in optocoupler/TRIAC circuit

I'm building a ac motor starter with a optocoupler (FOD4218) and a TRIAC (BTA16), one for each phase in a three phase 400V system. I have a question regarding the circuits that can be found all over ...
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2answers
230 views

Choosing Diodes for 3-Phase Rectifier

I'm building a rectifier to rectify a 3-phase signal for part of a school project, so I'm not working at these power levels without help and supervision. This seems to be an appropriate circuit as ...
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0answers
48 views

Determine active and reactive power from voltage and current over time in a three phase motor

How does one calculate active and reactive power from a set of data containing voltage-time and current-time pairs if the waves are not sinusoidal? I understand that apparent power in an induction ...
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3answers
63 views

Power on a three-phase system

Given a balanced three-phase voltage source and unbalanced loads connected in wye whose individual apparent power dissipation and power factor are given, find the the line currents. What is your ...
1
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1answer
57 views

AC Machine Stator Winding

In designing a 3 Phase, 4 Pole, 24 Slot AC machine assuming a RYB phase sequence i am confused on the starting point of the blue phase. The calculations, table and diagram look like the following. ...
3
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2answers
177 views

Three-phase Y and Delta Configurations Polarities

Please take a moment to look at the three-phase Y and Delta configurations pictures below (The pictures are screenshots taken from the “All About Circuits” online book). The first picture (Y ...
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1answer
37 views

3-Phase Generator Frame Ground

I have a couple of basic questions on three phase generator connections. I am trying to connect a three phase machine (datasheet) as a generator to a three phase load on a breadboard, as shown: ...
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0answers
53 views

Using the ADC on Cerebot mx7ck Pic32

I'm looking to use the ADC on the cerebot mx7ck (pic32) dev board to sample 3 input sine waves on three separate channels. However when I run my code, it appears as if I get the same sine wave from ...
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2answers
87 views

Calculating Active power in 3 Phase

When calculating the active power in the 3 phase Star, and Delta formations, there are two different currents used depending on the layout. I have shown my working below, with what I have been taught. ...
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4answers
565 views

Why and How does Power Plant generate Watts?

I know my question is stupid, it is stupid because I am not understanding it correctly. I thought two of following is required to calculate watts. Voltage, Current or Resistance/(Impedance in AC) is ...
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votes
1answer
65 views

VFD and Car Batteries

Can I use a VFD to drive a 3 phase motor if I drive the VFD with 48V from some series car batteries? The VFD has a single phase input and 3 phase output. Is it just a rectifier in there that charges ...
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2answers
93 views

Grounding a 30KVA isloation transformer

My company does audio visual services. When we use a single 120/208 VAC Three-phase "Y" power source for lighting, audio and video we get noise caused by the lighting dimmers injected into the audio ...
2
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1answer
258 views

How to determine phase angle of a three-phase circuit

I am experiencing difficulties with a question: A balanced three-phase load shown in the diagram is connected across a 380V, 50 Hz three-phase supply, ABC phase sequence. The voltage VAB is taken ...
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3answers
1k views

Line to Line or Line to Neutral voltage to calculate 3 phase power

I am confused as to whether or not I should use the line to line voltage on a 3 phase motor or the line to neutral voltage to calculate power? Would someone please be able to fill me in, and possibly ...
0
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1answer
79 views

Possible methods to control the voltage of a variable 3 phase power supply for an electromagnet?

The only solution I can think of is a three phase variable transformer, are there other methods? If so, what is the standard or accepted method to control the voltage of a variable 3 phase power ...
0
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1answer
103 views

How do I calculated total current on each line with an even number of circuits (unbalanced)

In the first example I was calculating the current each line would see for the purpose of sizing wire. An EE told me my calculation was wrong and that phase A would see 74A not 64A. I'm wondering ...
2
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3answers
1k views

Are normally open contactors virtually safe from failing closed?

Quick question: are normally-open contactors (which I assume are simply high breaking capacity relays) virtually safe from failing closed? I want to cut off a 400V 3-phase supply using an emergency ...
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0answers
66 views

3 phase currents come from 3 windings of a generator. But where is the neutral come from?

3 phase currents come from 3 windings of a generator. But where is the neutral come from?
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0answers
39 views

Exercise on a three-phase system where to evaluate the indication of the wattmeter

I have the following three-phase system where I have to evaluate the indication of the wattmeter W. Available data is: V = 380 ...
0
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0answers
72 views

3 phase stabilizer for single phase power

I just moved to a warehouse with single phase power (210 V? The power from the transformer is 3 phase.The power first goes to landlord's building before coming to the warehouse.) I have a Lioa dr3 30 ...
0
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1answer
106 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
95 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
211 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
84 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
450 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 ...
0
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1answer
48 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
1k 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, ...
0
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0answers
956 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 ...
4
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3answers
8k 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) ...
0
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1answer
160 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 ...
0
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1answer
219 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 ...
2
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0answers
110 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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0answers
35 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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1answer
305 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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2answers
140 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
3k 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
87 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
115 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.