AC power with three legs run 120 degrees out of phase

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2answers
47 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 ...
1
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0answers
26 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
43 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
23 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. ...
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2answers
64 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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0answers
24 views

Angles of phase displacement between phase and line voltages in star connected transformer

I recently did a lab in class which required using an oscilloscope to measure the phase difference between the line and phase voltage of a star to star connected three phase transformer. Two of the of ...
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1answer
31 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
22 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
58 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
514 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 ...
0
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1answer
39 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
59 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 ...
1
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1answer
152 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
289 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
59 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
61 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
748 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
50 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
33 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 ...
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0answers
45 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 ...
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1answer
76 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
67 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 ...
1
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1answer
132 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
58 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
234 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
36 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
536 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
537 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
3k 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
140 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
127 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
84 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
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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0answers
53 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
221 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
117 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
2k 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
71 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
99 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
445 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
75 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
66 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
101 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
166 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
4k 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
131 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
159 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
69 views

Calculating phase angles from symmetrical components

I'm getting the following values from a meter: ...
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0answers
77 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 ...
0
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3answers
1k 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 ...