Questions tagged [three-phase]
AC power with three legs run 120 degrees out of phase
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Quality Check of a Brushless DC motor on an oscilloscope
I am Quality Checking some BLDC(Brushless DC) motors with an oscilloscope by connecting the BLDC to a drill, running it and viewing the output on my oscilloscope. I have been checking the Vpp(Peak to ...
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Three-phase motor Delta/YY connection diagram and windings troubleshooting
I am trying to troubleshoot this 1.4 kW three-phase motor and I'm unsure how its internal windings are interconnected or whether they are shorted.
On the plate it says "Delta/YY 400 V", and ...
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What would be the voltage difference between two phases shorted together and the third phase?
I understand that it would be catastrophic for the two phases shorted together.
Say the line to neutral voltage is 2 volts and line to line voltage is √3×2 volts.
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3 Phases measurement using a RP2040 mcu to check if all phases are available
I did build a single Phase voltage measurement controller and works.
The basic measurement methode is as this.
The Diode 1N4007 is used to eliminate the negative half cycles. Using a voltage divider ...
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Connections in 3-phase AC circuits
Does the supply voltage refer to the line voltage or the phase voltage here?
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2 wattmeter method for measurement of power in 3 phase AC circuits
Could someone please explain the concept of the lagging and leading pf in 3 phase AC circuits with respect to these special conditions
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Screw terminal damaged in input 230 V three-phase power supply
I use screw terminals for a 230 VAC three-phase power supply, but it blasts in many PCBs, so I want to replace it. What would be a better solution?
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Need to convert 240vDC to 3-phase "high leg delta": can an inverter be avoided? [closed]
I want / need to take a 3kW, nominally 240vdc say again DC and obtain "3-phase, high-leg delta (aka wild-leg delta) from it.
(I won't answer questions on why, but if I feel the need later, I'll ...
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What will actually happen to my 3 phase motor -- low and unbalanced voltage?
Dr.Google tells me:
"Voltage unbalance exceeding more than 2 percent in three-phase systems can cause current unbalance among the windings. These, in turn, can cause an increase in winding ...
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How to calculate power of three-phase equipment when only measuring amperage of one phase
I am trying to obtain a wattage measurement from an air compressor using only an amperage measurement from one of the conductors, and the nominal voltage stated on the machine.
The purpose of the ...
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Why is my borewell pump drawing 6kW when it's rated 3kW? [closed]
For the past 6 months there has been increase in my electricity bill. The reason is that the maximum demand is higher (6kW) than the sanctioned maximum demand (3kW.)
We have a 3HP 3 phase borewell ...
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Relative short-circuit impedance of a three-phase transformer
I am trying to calculate the (absolute) short-circuit impedance from the relative short-circuit impedance of a three-phase transformer. I am not sure if my formula is correct, especially concerning \$\...
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Can I get a neutral from a three-phase supply using a step-down transformer (415 V to 230 V)?
I have a three-phase supply voltage, between them is 415 V.
Can I connect a 415/230 V step-down transformer between any two phases and use the output of the transformer as phase and neutral?
Or ...
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SSR or TRIAC for 8kW three-phase kiln
I have a PID-controller that uses VAC as the control signal. The kiln will be heated and cooled in stages with specific speed (t oC per hour), mainly for ceramics with crystal glazes.
Manufacturer ...
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How to design a phase selecting switch without using a relay?
My project is an automatic phase switching device which will detect the phase unbalance between the phases and switch the load to the healthiest phase. The block diagram is below:
The project focuses ...
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What happens when a grid tie inverter is out of sync?
Background:
I have a growatt sph6000 tl bl-us which is a split-phase hybrid solar inverter. I purchased this with the assumption that my grid was split-phase, with the two lines offset by 180 degrees. ...
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Power Quality Measurement & Reporting Standards
I'm analyzing power quality in low and medium voltage facilities (50/60Hz; 0.48 - 69 kV; factories, campuses, etc.) while trying to apply existing standards wherever possible. In addition to demand ...
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Single-phase diesel generator to three-phase modification
I have a 220 V, single-phase diesel generator and I would like to know if it's possible to modify it to generate 400 V, three-phase. I have never tried this before.
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Single Phase (L1&L2) in 3 Phase Supply Calculation
I have multiple single-phase loads required to be powered from a 3 phase supply with neutral (208/120) V. I'm going to tap to (L1, L2) & (L2, L3) and (L1,L3) respectively. Assuming the load was ...
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AC voltage and frequency measurement
I am planning to measure the AC voltage from a 3-Phase ranging 480V/690V effective value with almost 10-20% tolerance => a max. peak of around 1171V.
I try to use protective impedance to step down ...
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How do utility lines wire transformers to go from 3-phase power to residential split phase?
I'm trying to understand how power distribution lines go from 3-phase to single-phase and haven't been able to find a concrete explanation.
I understand that power companies transmit with 3-phase ...
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380 V to 220 V three-phase
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I purchased a heat press that was supposed to be 220 V, 3-phase, but 380 V showed up. It is 12 kW, 32 A, no moving parts or motors. It came from overseas so ...
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Calculate or estimate 3-phase 400V heat pump (inductive) load
My water heating system (CTC) consist of a air-to-water heat pump and a water tank with an immersion heater. It is all powered from the same electronics pack and hooked up to 400V (3-phase) with a 25A ...
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Difference in amperage at the plug vs at the source (three-phase wye, 120 V and 208 V loads)
I'm trying to understand the difference between how my work calculates power at the load vs how we calculate the sum at the source.
We run temporary power and plug in several hundred industrial ...
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How does the control of a three-phase PWM rectifier work?
I have been studying the control of three-phase PWM rectifiers i.e. control of the below power electronics circuit:
This circuit can be modeled with exploiting of the space vectors in the stationary ...
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How to include dead times into the model of the three-phase voltage source inverter?
I have been developing a Scilab model of the three-phase voltage source inverter. I have started with the idealized model where I suppose that in each of the inverter leg one transistor can be turned ...
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What is the initial phase of the rotating magnetic field of a 2-pole stator?
How can one determine the starting phase of the rotating magnetic field? What I mean is, Are you able to determine the direction of the magnetic field, when knowing the values of the 3-phase stator ...
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Solving the problem of connecting a high-current, single-phase load to a three-phase balanced network
I am an electrical technician working in a hospital. In the laundry room, all the cloth washers contain three-phase motors which are balanced loads connected to a 140 A circuit breaker. The ...
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Calculation single phase and three load connected at the same time to three phase network
I have a single phase load (90 A 230 V) and 2 three phase loads (7 kW 400 V 3 phase/9 kW 400 V 3ph+N) connected at the same time to a three phase network.
How the 3 phase calculations (line current of ...
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What is the phase displacement of fault currents on each phase in a symmetrical fault?
In a Line-Line-Line-Ground symmetrical fault, is the fault current on each phase also displaced from each other by 120°?
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3-Phase BLDC Motor Brake
I want to be able to stop my motor instantly. When I am doing that with a single-phase motor, I just pull the phase to the ground and the motor instantly stops. Am I supposed to do the same with 3-...
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Base Impedance of three-phase circuit
I want to solve the base impedance of the three-phase delta-connected supply.
Let a three-phase delta supply of 10 kV and 100MVA be connected to a balanced load of three 0.6 ohm wye-connected ...
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Output voltage halved in 3-phase SPWM inverter simulation
I am just trying to simulate a 3-phase inverter connected to a star-connected load controlled through sine PWM modulation.
In real life, I would expect a carrier that would go from zero to one. As ...
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Measuring 3-phase power. How to calculate?
I'm designing AC power consumption meter device for apartment based on popular MCU and current/voltage transformers. Currently I successfully managed to measure current and voltage in each phase line ...
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Solid State Analog Phase Shifter
I have a single A/C source that I would like to phase shift into three different phrases, offset by 120 degrees, essentially resulting in something like below:
I've seen out in the real world, folks ...
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How best to control 6 IGBTs for 3-phase controlled rectification?
I am using a BLDC as a generator. I am hoping to get a steady 50 V at 100 A. The frequency and voltage of the 3-phase output are variable with motor speed and linearly related, and I measure a ...
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Will a 3-phase variable frequency drive have any effect on voltage differences between phases?
The national power provider here is not great. There is often a 10 - 30 V difference between phases.
Will the voltage exiting a 3-phase variable frequency drive be the same as the input voltage, or ...
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What is the power rating for a 3-phase transformer based on the secondary voltage?
We want to install equipment on a 60 Hz, 400 V Delta system. The equipment is not suitable to work on a 400 V Delta system, therefore we can place a transformer to create a star configuration and are ...
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Transforming a Δ source to a Y source
When having Y-Δ or Δ-Y 3 phase circuits, it is more convenient to transform the source configuration into the load configuration to make the circuit easier.
When going from a Δ source with line-line ...
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How can I properly convert two phase AC supply to three phase using capacitors?
I have an AC 3 phase delta connected submersible induction motor with specifications 440 V, 10.5 A, 5 HP, 2800 RPM which is already fitted with a 3 phase PF correcting capacitor in parallel. The ...
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FOC RPM control strange behaviour
so we have been struggling with a particular issue on our Motor controllers. Before i explain the issue in detail with pictures. Let me setup the context of the hardware we are using.
Motor controller:...
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Speed control in FOC system
I kinda understood how field-oriented control works but I have a question in my mind. How am I gonna control the speed of the motor? With which variable am I gonna be able to do that? For example, in ...
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I am getting weird voltages on three phase to ground. What's wrong?
I had to measure our three-phase service for configuration of new equipment. This is in Indiana. Line to line reads about 246 V, but line to ground is 1.4 V on line A, 42 V from line B, and 44 V from ...
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vfd 3 or 1 phase input how is voltage adjusted
I bought a cheap VFD (variable frequency drive), it takes 3 phase input, but allows too for 1 phase input connecting the neutral and phase on the the first and third phase input. The vfd to my ...
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Match each of three exact phases from two different supplies (distribution boxes)
I have to replace 3 phase cable powering refrigeration unit from one distribution box to another.
For refrigeration compressor is required to preserve same phase sequence.
Unfortunately, I don't have ...
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Can a single phase supply from a 3 phase outlet result in excessive power meter readings?
Here in Turkey typical residence supply is single phase at 230V.
Years ago a friend's father built a residence and arranged for a three phase supply as he felt that this would provide a more stable ...
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Possible to detect phase number in a three-phase system?
I have a 400V three-phase [TT system][1] that I use for my company in Italy.
I was wondering if there is a direct way to detect the phase number at any point in the wiring.
I have the phases numbered ...
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PMSG connected to three-phase PWM rectifier - Simulink
I am implementing a controller for a three-phase rectifier in order to have a constant DC-link voltage.
I have a PMSG which is connected to the rectifier and a capacitor (DC-link); I want to model ...
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Meaning of 3P+N/2 in circuit breaker
In the following selection table of Legrand DPX3 three phase molded circuit breakers (Legrand 422000 to 422013) along with the familiar 3P and 4P circuit breakers, there are 3P+N/2 circuit breakers (...
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Is the two-wattmeter method applicable for an unbalanced source?
In balanced three-phase systems we can use the two-wattmeter method to measure total power. What about unbalanced sources and/or balanced/unbalanced loads? Can we use it for both delta and wye ...
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