AC power with three legs run 120 degrees out of phase

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38 views

Measure 3-phase Power with Lecroy Waverunner

Please note that experience with a Lecroy Waverunner Oscilliscope is most likely required to answer this question. I'm attempting to measure the power draw of a brushless 3-phase motor with a Lecroy ...
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2answers
25 views

Phasor math for balanced 3 phase circuit

Are there any mathematicians in here? I am currently reading my ECE text's chapter on AC machines and i referred to some material in the chapter that first discussed AC circuits. In the photo below ...
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1answer
27 views

Confirm AC generator output frequency calculation

I am working on a project to build a small generator based on a 12 magnet, 12 pole, (6 pole pair) rotor with shaft speed of 2800 RPM. (Output voltage, 240 V AC, 4 kW.) Estimated load will be 3.5 kW,...
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1answer
46 views

Strong and a weak grid? [closed]

What is difference between a strong and a weak grid? How can these be simulated in simulink? ?
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1answer
47 views

3-Phase Permanent Magnet Alternator with Regulator/Rectifier (SCR) Output Waveform

So I've been troubleshooting some electrical problems with a motorcycle charging system, and I need a little assistance understanding the output waveform: Per an article (which I don't have enough ...
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1answer
47 views

Three phase system - power factor

I need help with the following problem: Given symmetric three phase system (see attachment) of phase voltages with angular frequency ω=100rad/s, R=5ωL=100Ω. Find capacitance of capacitor C such that ...
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0answers
25 views

How many measurements does a typical phasor meqasurement unit (PMU) capture?

How many phasor measurements (voltage amplitude and phase angle) does a typical PMU capture from 1) transmission and 2) distribution lines? is it one, three, or more? Does this depend on the topology ...
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2answers
266 views

How to step up unregulated ~0.2-1V to regulated 5V

For a school project, I am building a small hydroelectric generator. It uses a 10v, 600RPM/v brushless Tower pro 3520-7t-8 motor, which, when geared up (I'll spare you the calculations here), should ...
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0answers
21 views

Measure the reactive power in a three phase system

In a recent lecture at university an assistant explained that in order to measure the reactive power in a non-symetric three phase system we should connect three wattmeters in the way shown in the ...
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1answer
62 views

Modification of a 3 phase AC motor [closed]

There is a permanent-magnet synchronous motor with an external rotor that I want to explore and possibly modify. To do this I need some answers to my simple question: For a given shape of stator ...
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1answer
42 views

Why is bi-directional current sensing required in sensorless BLDC field-oriented-control?

For the past few weeks I've been trying to understand Field-oriented-control for 3-phase motors. Eventually I would like to implement one. I've gone through dozens of application notes from Microchip, ...
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3answers
139 views

3 phase ac to 5V 50mA power supply

I am working on a 3 phase energy metering project using ADE7752 IC. I am stuck into getting the power supply part in a smaller form factor. Since energy measurement is being done for all 3 phases, ...
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1answer
43 views

Is full load current line or phase current?

If a question just asks for full load current, is this considered phase current or line current. Do I need to consider if it is a wye or delta because of this? With three phase power being ...
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1answer
51 views

Simple three-phase circuit question

Phase voltages of three-phase circuit with Y configuration are equal by absolute value and phase difference between them are \$2\pi/3\$ and \$\theta_A=\theta_B+2\pi/3\$ and \$\theta_A=\theta_C-2\pi/3\$...
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0answers
22 views

Comparing fault currents at a certain point in two different scenarios

As a part of my course exercise, I have been asked ...
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1answer
102 views

variable frequency three phase AC

I want to generate 1-150Hz+ three phase AC. Output voltage at maximum frequency would be around 240VAC and current around 40A. I have a few 60Hz three phase induction motors, drive shaft coupler, and ...
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1answer
42 views

Which formulas do I need to calculate current of a 3phase induction motor

How can I know the current a motor would require to run at a given RPM. Here are some values: 160 HP motor 325 volts 2300 RPM 311 ft/lbs of torque(not sure how useful this is) induction motor using ...
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0answers
34 views

ETAP software, creating a single line

I'm learning how to use the ETAP software and I'm supposed to create a single line. There is an automatic transfer switch that switches between the main switchboard and the emergency generator. In ...
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1answer
92 views

when does the neutral wire in a 3 phase system carry voltage?

I am curious, and I've found a bit of information online, but maybe its not clicking in my head... when does the neutral line in a 3 phase system carry voltage. i do understand the answer is quite ...
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2answers
593 views

3 phase induction motors with poles not equal to 3x

I am having trouble finding diagrams to show induction motors with poles not equal to 3x. Everything I find is 2 poles per phase. Can anyone explain and help me visualize, for example, a 4 pole 3 ...
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1answer
51 views

BLDC Current Driver Encountering Current Problems

The attached Schematic uses 6 N Channel Power Mosfets "IRL3303". I have wound my inrunner bldc motor with 180 windings per phase using a 26 Gauge Magnetic Wire. My motor is a 6 pole 2 magnets machine. ...
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1answer
300 views

3 Phase Voltage Inverter for BLDC motor. N mosfet getting hot. Why?

I am making a bldc motor and attached is my 3 phase current driver circuit. A,B,C represents the phases of the motor (Y winded). The sockets behing the bjt's go into arduino micro-controller. The bjt'...
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2answers
106 views

The leads of my 3-phase motor are incorrectly labeled. How do I determine the correct labels?

I connected my new-in-box 3-phase motor to my new-in-box VFD, following the instructions in both manuals and the wiring diagram on the name plate (low voltage configuration). With the power off, ...
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2answers
590 views

High voltage three phase transmission lines

The high voltage transmission lines in North America looks like this. If a three phase balanced circuit uses three voltage sources, would that mean that this pole in figure one is carrying the ...
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0answers
38 views

Purpose of resistors from phase to phase on 480V motor

I have inherited a project with a motor circuit that I cannot figure out the purpose of some resistors. It was initially designed for operation in Europe at 400V 50Hz. Since it is operating here in ...
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2answers
51 views

Complex power of a load

Simply, if there is a load that is 80kW and 95kVAR (inductive), can I then say that the complex power this load consumes is 80 + 95kVA or is there more to it?
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1answer
41 views

Is it possible to over-power a 3-Phase AC motor with a AC Controller?

If I have a 200kw motor controller, and a 30kw motor, is it possible to overpower the motor with the controller? My application is for an electric vehicle (golf car, small bicycle, and so on). I'm ...
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0answers
58 views

Dry Type E-I CRGO Lamination based 5KVA 3 Phase Transformer DELTA-WYE Winding Turns Calculation

I am basically a firmware developer so pardon my ignorance. I need to construct a 3 Phase 415V/50Hz DELTA Input Transformer. The core is 1.5 TESLA Max (as per stockist). I need open ended ...
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1answer
101 views

3 phase AC Voltage controller question

Hello I have a question regarding the operating characteristics of 3 phase AC voltage controllers, the images describe the relation in between Van and (VAC,VAB,VBC) The last image shows the resulting ...
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3answers
66 views

What fuses for 100A, 3-ph disconnects

I've been looking at 3 phase disconnects, and I'm uncertain what the rated amperage means in this context. Since each blade (phase) has its own fuse in a fusable disconnect, does that mean that for a ...
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3answers
148 views

Generation and transmission of electricity

According to my textbook the three phase power is generated so that the power that is needed to generate electricity by the torque remain constant. Another reason is that the summation of the three ...
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4answers
112 views

What is capacitance required for this 3 phase rectifier

In the diagram above I want to know the value and the rating of the capacitor that should be used for good rectification The Line to Line voltage is 400 , and by relation Vdc =(3√2 VL)/pi=(3√2 x ...
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2answers
87 views

What is the pole frequency of a three-phase LC filter?

Suppose I have this configuration: Assume L1=L2=L3 and C1=C2=C3. What is the pole frequency of this filter? Edit: As mcmiln says, this is not identical to the question here: Cut Off Frequency in ...
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1answer
51 views

Disagreeing 3-phase power

So this feels like a silly one but I'm absolutely stuck. I'm trying to balance the power between a 3 phase source and two 3 phase loads in parallel. One is a Wye and the other is a Delta: So I ...
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1answer
65 views

Why is inductance negative in this triphase mutual inductor?

Suppose I have a threephase circuit with a mutual inductor on the first and second phase (V2 and V3). One way of solving the circuit (ie finding the phase currents) would be the following: convert the ...
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1answer
56 views

Voltage between AC phase and DC link

Let there be 3-phase rectifier connected to the standard electricity grid with 400V between phases. Measuring voltage between one of the phases (AC) and negative terminal of the rectifier output (DC), ...
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1answer
52 views

Max Current through Neutral in wye-wye 3phase circuit

Assume that you have a wye-wye 3 phase circuit. Each of the 3 phase wires can take a max of X Amps. What is the max current the neutral of the circuit could have? Is it possible for the neutral ...
0
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2answers
53 views

Hooking up a variable frequency drive

I have a 3-phase blower motor that I am looking to control from a Danfoss VLT 2800 that I purchased on eBay. I am going through the manual and I see this table for the mains connection: . I have in ...
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2answers
2k views

How to wire 3 phase motor to VFD

I am trying to wire a new motor to a variable frequency drive (VFD) and having some trouble figuring out how to wire the motor to the VFD. The motor is a 1 HP, 3-phase, 208-230/460 volts, and I'm ...
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1answer
96 views

Design of three phase thyristor circuit for temperature controller

Circuit is powered by 3 phase, 415 V AC. This is connected to nri halogen tubes to heat a chamber up to 20 kW and 700℃. I have to control temp using delta controller DTA 7272 which will sense ...
0
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1answer
43 views

Calculating phase currents of an automotive alternator

I have an automotive (3-phase) alternator with peak rated output of 150A at 14V (after rectification, of course). How can I determine phase (AC) currents in this situation?
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1answer
187 views

why the stator frame of a 3-phase generator is made up of cast iron?

I don't have a good knowledge of engineering materials, so please answer the following questions with reasons. Why is the stator frame of a 3-phase generator made up of cast iron? Why is the ...
0
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1answer
47 views

Symmetrical components: phase voltages

In the following question on symmetrical components, the 11kV of the source is the line-to-line voltage. When using symmetrical components you want to be working with line-to-neutral voltage. Am I ...
0
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1answer
102 views

How to derive apparent power formula for three phase AC system?

I know that the total power output of a three phase system is √3 EI cosØ Where E and I are the line voltage and line current. Now my question is how can one derive the apparent power equation i.e.. √...
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6answers
986 views

Why do we need to install a power transformer for each high building?

I live in area where many high buildings are being built. Each building is more than 10 floors. A special room is made next to the main entrance or the garage. The room is designed for installing a ...
2
votes
2answers
255 views

Power factor correction for LED lighting on a generator

I'm the electrician for a club that builds an illuminated carnival parade float, and historically we've lit our float using around 10,000 x 40w incandesant lamps powered by a 800kVA 3 phase generator. ...
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1answer
109 views

How to set phase delay for a three phase igbt rectifier

I have a three phase igbt rectifier like so. three phase voltage = 690V. how to set the phase delay and DC link capacitor value(F) to get Vdc = 1070. I have updated the complete simulation with the ...
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1answer
526 views

IGBT vs. SCR rectifier

I simulated three phase rectifier using a thyristor like so: I get the expected result. But if I change the thyristors to IGBTs as shown below, it does not work. Why do these two circuits behave ...
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2answers
100 views

Measuring 400V three phase large consumer power

I need to measure the power consumption of a large (11kW) electrical motor during various stages of operation. I have a few interlinked questions: I'm interested in the power the operator of that ...
5
votes
2answers
3k views

Why are the letters U, V and W used in AC motors to represent the windings?

I am connecting up an AC motor and was wondering if this labeling system was representative of something? Or just another set of letter like X,Y,Z? I could not find any information regarding this in ...