Questions tagged [three-phase]

AC power with three legs run 120 degrees out of phase

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Watt meter connection in three phase circuit

Does the zero point "where all the voltage coils are linked " in this watt meter connection indicates that the power measured by each one of the watt meter is the phase to neutral or the ...
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How do I power this 400V motor from 230V? [closed]

I just bought a lathe with a motor that used to be connected to 3 phase 400V. I am trying to power it using single phase 230V domestic mains. I understand that I can use a VFD to provide the extra ...
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How is my isolation transformer not short circuited?

I received a 3 phase 240 to 208 isolation transformer, and I am unsure how the current configuration (as it was shipped to me) would not cause a short circuit. When I do an ohms reading on the high ...
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How can I choose the right stabilizer for a 3-phase 415 V supply system?

I have a question about how to select the right capacity of voltage stabilizer for a 3-phase supply system. That system has the following type of load and capacity: Two 1 hp 3-phase motor, 440 VAC (...
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How do you find the voltage in this three phase circuit?

The picture shows a circuit of 3x380/220V and it is asked to solve for the indication of the voltmeters. I can´t get any hint on how to find the Vc voltage. The box with the delta symbol indicates ...
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How do we calculate the current through two impedances in series by knowing the voltage of one and the impedance of the other?

I have a problem where I know the apparent power consumed by a Y-connected load and the line impedances, which I already reduced to work just with the line power (300kVA): the source and two ...
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Should electric dryer work on NEMA 10-30 receptacle with 163 V to ground in commercial building with 3 phase service? USA [closed]

An animal shelter (in USA) where I volunteer has a new 240V Maytag electric dryer that will not operate (when "on" is pressed, the electronic panel gives a single brief flash of all LED's, ...
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What is maximum possible current in neutral wire in three phase connector?

What is the maximum possible current in neutral wire in eg. 3x16A three phase connector? Is it possible that current leads or lags more than 90 degrees? Edit: Could the maximum be 16A∠0° + 16A∠(120°-...
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Make a 0.5 HP, 3-phase motor work with single phase voltage with capacitor [duplicate]

I have a MGM Varvel's SM71B4 AC motor which runs on 3-phase that comes out of a Schneider Electric's VFD called Altivar ATV12H037M2. The VFD has failed and doesn't show the input voltage, so I decided ...
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How does a power meter differentiate between three-phase and single-phase loads?

How does a three-phase power meter (for example the one used by my power company) know the difference between a single three-phase load and multiple single-phase loads? For example: a three-phase ...
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Breaking into a supply cable

I am just after general opinion on a situation. We are looking to install energy monitoring at a particular location. The company does not want the mains supply switched off and we need to install our ...
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What is the best way to convert 3ph 380VAC to 3ph 0V >> 450VAC in range of 800 kW?

I have a company that makes servo AC voltage regulators and some other transformer-based products, and today some of my customers asked me to give him a quotation for an 800 kW Variac, the biggest one ...
AlMoutaz Billah's user avatar
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Bugged Clarke Park transform on three-phase signal using Python

I'm supposed to apply a Clarke-Park transformation to an electrical signal so other people at my office can study the "quality" (?) of said signal. I was given a Jupyter Notebook replicating ...
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Why is wye-wye connection rarely used?

Fitzgerald's Electric Machinery book explains the following on chapter 2.7: ... The delta-delta connection has the advantage that one transformer can be removed for repair or maintenance while the ...
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Control P-channel and N-channel MOSFETs by common PWM signal

I want to create a very simple 3-phase inverter that is easy to understand, e.g. without using MOSFET drivers. I decided to use logic level P-channel MOSFETs on the high side and logic level N-channel ...
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Is there a 3-phase to DC converter that draws current proportional to voltage?

Of course, 3-phase alternating current can be converted into a rippling direct current with a 3-phase bridge rectifier. This design only draws current from the two phases with the most voltage ...
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Can I use just two relays to switch between two 3-phase brushless motors sharing the same driver?

I have a 36V DC 3A (max) 3-phase brushless motor with it's own driver. I have a spare motor and I want to leave both motors connected to the same driver all the time, but only one motor will ever be ...
Rodrigo's user avatar
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3 phase induction hob, single phase wiring [closed]

While installing this 3-phase appliance I came across these diagrams which have been bugging me a bit, therefore it would be nice to find out what is the correct way to wire this up and what is the ...
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Power calculation for single phase heat treat oven

We have an old heat treat oven that was intended to run off of 240V single phase (US). In actuality it is running off of two legs of a 3 phase 480V->208V (delta to wye) transformer. The ...
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Single phase current requirements and minimum transformer requirements

To start, a generator is not an option for my situation. I am looking to produce 208 V 3 phase delta using a rotary phase converter to power two robots. This is my first attempt at generating 3 phase ...
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Understanding the effects of source faults on load voltages in three phase systems

I have heard that an open circuit in a wye connected source affects the voltage across the loads (whether they be delta or wye), as shown in the following diagrams. I have also heard that an open ...
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Which motor wire corresponds to which phase

I have a three phase motor having 3 wires: red, black and white. But the product datasheet does not tell us which colour wire corresponds to which phase.
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Behavior of an electric stove on 1-phase vs. 3-phase

I want to replace my current electric stove that's powered by a single phase line with a 20A fuse. I'm in Germany with 230V AC. The overall power that can be delivered is 20A*230V = 4.6kW. I'm looking ...
Peter - Reinstate Monica's user avatar
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Ways to charge a VERY LARGE capacitor in a 3-phase bridge rectifier circuit

I need to charge two 1500uF-450V capacitors off of a 3-phase 220Vrms-60Hz line using a very robust bridge rectifier (datasheet) as well as both capacitors datasheet (datasheet). Here's the simulation ...
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Generator control over active and reactive power

My background is in electrical installations. I have been put on a project that is assessing generators. I would like to tap into the experience of those on this forum. I am asking these questions ...
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How do calculate power consumed by a BLDC motor using two-wattmeter method

From https://www.studyforfe.com/blog/steps-for-solving-the-two-method-wattmeter-problem/ : $$\begin{aligned} W_1 &= V_L \cdot I_L \cdot \cos(30°+\phi) \\ W_2 &= V_L \cdot I_L \cdot \cos(...
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Best solution for generating three phase for robot controller

I have a Staubli CS9 controller. This controller requires three-phase 400-480v or three-phase 200-230v. I do not know the controller's max amp draw, horsepower equivalent or even leg to leg/ leg to ...
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3-phase unbalanced power supply [closed]

I have a 3-phase power supply with 115 V phase. I am giving 2 of it phases to AC-DC converter with DC side having 50 W of load. The 3rd phase is no load. There is no neutral connection required for my ...
Vivek Sinha's user avatar
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Is there a difference in reading power for 3 phase as opposed to 3 single phases?

I have 3 phase supply to my house. And I have solar on two phases, that use 2XTesla Powerwall 2 batteries. Based on the Tesla reports, my power bill should be a lot lower than the charge of $400 to $...
Rohit Gupta's user avatar
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1 answer
187 views

Is this Medium Voltage Distribution Delta or WYE

You have been extremely helpful before on a few things. I have another question. This is involves medium voltage 15 kV AC 3 phase distribution 3 conductor plus ground, shielded cable. Braided/twisted ...
GreenBlueOrange's user avatar
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Is this possible? 1phase splitphase auto transformer connected to A 3phase grid

Dear reader, I have a question about a single-phase auto transformer which is connected to a three-phase electricity grid. The windings of the auto transformer are on a common iron package. The ...
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Why does this solid state relay have voltage on both terminals?

I have an RA4850-D12 [1] SSR in an injection molding machine. The machine uses 240v, 3-phase power. The SSR is in the diagram for the circuit on page 7 for K81 [2]. You can see that terminal 1 of the ...
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Sizing capacity of a 1-phase breaker to feed a VFD and a 3-phase motor

I have a 3 phase 2HP motor that draws 5.8Amps at 240v I want to feed it with a VFD with the following specs: VFD rated power: 4kW 1-phase input: 36 Amps 3-phase output: 18.5 Amps The VFD is of ...
Max L.'s user avatar
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Could a device connected to one MCB/phase affect a device on another MCB/phase?

I have a 3-phase 230V residential supply. It's divided among 3 groups of MCBs all powering single phase devices. The problem I'm having is that whenever the air conditioning (single phase) turns on ...
Pavin Joseph's user avatar
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Can I utilize 3 phase power in a single phase appliance by connecting all 3 lines in parallel?

I can't seem to find an answer to this. Assume we have a 400V three phase power source. Connecting phase-to-neutral will give 240V. If you connect them in parallel you should still end up with 240V AC....
Nederealm's user avatar
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Is the relationship between impedance and three phase apparent power different in Delta and Wye?

I looked up this article https://www.electricalpereview.com/base-impedance-single-three-phase-values-equal/ and I am really confused about the final equation. The author says that this applies for ...
dogdump123's user avatar
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3-phase motor body earth

A 3-phase 90 kW motor connected through VFD tripped due to over load. Frequency was set at 49 Hz. I lowered the frequency to 42 and the motor is running smoothly now. The current in phases were as ...
Sohaib Rehman's user avatar
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Measuring 240v 3-phase circuits with an oscilloscope

I have an injection molding machine that has some odd behavior* going on in it which I need to diagnose. I've probed around with a multimeter, but I think I need to understand deeper what is happening....
Maxthecat's user avatar
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3 phase motor in Steinmetz connection on a single phase supply direction change problem

I want to run a 3 phase induction motor on a single phase power supply. I'm aware of the low operating power & low starting torque in this configuration. My load & duty cycles are also not big,...
icyGuy's user avatar
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If the three-phase voltages are square waves, is there a neutral voltage in a balanced wye-wye configuration?

I am analyzing a wye-wye configuration circuit. Both the source and the load are balanced. The source is three-phase. Each phase is offset by 120 degrees. Neither the source nor the load is grounded. ...
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How to release "idle" brake of a three-phase motor? [closed]

I am using a three-phase motor (Segmotor SS Serie) with a VFD (Delta VFD-EL-W). When not under tension, the motor's shaft is blocked by a brake. How can I bypass this brake? (either directly on the ...
Jo Kolski's user avatar
2 votes
1 answer
66 views

Is it possible to use a dedicated connector to a standard enclosure?

I am a mechanical engineer updating a small machine at the factory that I work for. Basically it is just a motor spinning an axis using a V-belt. I need to put all the electrical components inside an ...
Gabriel's user avatar
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3 votes
3 answers
424 views

How do you specify the requirements for 3-phase load center (breaker box)

I have listed the eight required circuits in the image/table below. There are three 3-phase 208 V circuits, and five single-phase 120 V circuits. What I'm looking for specifically is how many amps ...
Brice Edward Furr's user avatar
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1 answer
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CLOSED: Naive Question - VFD powered receptacle to power European 3-phase 2.2 kW 50 Hz powered equipment

I've updated the title as "CLOSED" because the thoughtful responses have answered my naive question. I did quite a bit of research yesterday and this research, combined with the forum ...
AlphaBob's user avatar
1 vote
1 answer
136 views

Why connect a 3-phase alternator's star-point to a rectifier bridge?

I noticed while troubleshooting a Denso alternator that the stator's star point was connected to the rectifier bridge. While probing with a multimeter, I think the schematic looks something like the ...
Kenn Sebesta's user avatar
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219 views

Correct understanding of torque constant for BLDC using FOC

I have a BLDC motor with sinusoidal windings that I drive with FOC technique. With my recent knowledge earned by implementating FOC, I got confused with the typical motor constant given in ...
Victo Rien's user avatar
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Maximum Current in 3 phase ac charger for vehicles

I have seen a couple of AC EV Chargers that take in 3-phase inputs. For US it is 120V. For UK and Europe it is 240V/220V. My question is, I want to design the fuse and other MOV components and relays ...
Jacksmith's user avatar
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Resistor power ratings & Package

I have this circuit that detects the phase difference between 3 phases. My questions are, I'd like to know the power ratings and packages of the 1M and 1k resistor. Also, what should be the ratings ...
Freshman's user avatar
2 votes
5 answers
897 views

Purpose of Isolation in Power Supplies

I have a general question. Suppose, I have a PCB, (an electronic device), which is powered from the Electrical socket (from mains grid). Let us assume it is single phase. When the mains power supply ...
Freshman's user avatar
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224 views

Detection of 3 phase system

I need some help with the below circuit. Circuit: 3-phase AC circuit (3 phases and neutral). 120deg phase shift between the 3. I need to provide a signal to the Microcontroller. If one of the phases ...
Freshman's user avatar

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