Questions tagged [three-phase]

AC power with three legs run 120 degrees out of phase

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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
68 views

Bizarre problem with 3 phase WYE system

I have a weird problem with the electricity in my house. The house has a three phase municipal supply 400/230V WYE electrical system. The house is old and already I have had problems with water ...
2k views

Snubber circuit for 3 phase inverter designed for BLDC motor

I'm designing a motor controller for 3-phase BLDC motor. I'm using following components, Gate driver - IR2184 MOSFET - IRF540N The complete circuitry and output waveforms are available here. I have ...
105 views

Equivalent DC circuit of 3 phase induction motor

I'm currently trying to model a simplified circuit of an inverter + 3 phase induction motor. For now, I want to represent the DC link as an ideal independent voltage source. To keep this example ...
269 views

Can a triphase current regulator be used with just two phases?

My house is located somewhere with power problems, these have been going on for 15 years and will probably never be fixed. Family lives next door and I want to regulate the power to both my house and ...
39 views

Difference between THD equation and design circuit current

Why does the summation of design circuit current equation (Ib) start with 1 while for calculating THD the summation starts with 2?
50 views

3 phase transformer efficiency calculation

This is an assignment. No matter how hard I try the answer is never what I expect. Here is the question: Three single phase transformers, each rated at 12 kVA, 120/240V, 60Hz, are connected to form a ...
188 views

What happens to the Real and Reactive power when I increase the excitation current in a 3-Phase Synchronous Generator?

Basically my doubt is, for the same load, why does the Real power remain constant when I increase the excitation current?
29 views

Three-phase rotary converter wiring questions

I am installing a 30 HP three-phase rotary converter on a 200 amp service in my home shop. I intend to run a CNC milling machine with a 15 HP motor. I am using 2 AWG wiring in 1" shielded conduit ...
41 views

Creating a 3 phase current

For an experiment (generating a travelling magnetic field) in high school I need a 3 phase current. My school does not have access to 3 phase power. Therefore I need to generate the 3 phase power out ...
53 views

Understanding Per Unit System

I am having issues understanding the Per-Unit System calculation. I don't come from an exact power engineering background so I hope my question is not too stupid. For the calculation of base ...
132 views

Switching power line phases with inductive load

I have one question related to this schematic: Scenario: Source 1: AC source 220VAC, 50Hz, 120Āŗ Source 2: AC source 220VAC, 50Hz, 0Āŗ If I want to switch from source 1 to source 2 or from source 2 ...
481 views

Three phase converter - capacitor switching

I've started building a single to three phase converter. My research started with the likes of this paper. I've set a bank of 40uf/440v capacitors up and a potential relay. The relay is a Supco SUPR. ...
29 views

Space vector and bias voltage

I am trying to learn the space vector modulation but I am wondering how is the bias voltage in a 3-phase system regarded by the space vector?
48 views

Connecting a three phase drive - Should N connect with L3?

I have a simple question. I'm going to connect a three phase motor. 'Three phase source -> drive unit - > three phase motor' But between the three phase source, should I connect N with L3, or ...
122 views

PWM phase voltage and current measurement for power consumption calculation for a BLDC MOTOR

I have been trying to log both voltage and current from the battery of an electric two wheeler for finding out efficiency at inverter, battery level.
891 views

How to design a 3-phase resistive load bank?

We are trying to design a 3-phase resitive load bank to test some step up transformers. We are receiving 3-phase 208v and stepping up to 3-phase 600V with 3-step up transformers wired in delta. Its a ...
60 views

Phase and voltage conversion

I have a hypothetical question in regards to phase conversion and transformers, more specifically on their combination. I am not a certified electrician or engineer, so I don't know what all goes into ...
481 views

3 phase BLDC sinusoidal drive using PWM controller and/or DSP?

My background is mechanical engineering (robotics). I apologize in advance. I have a sensitive torque ripple (Vibrations) application and would like to use sinusoidal drive to run a 3 phase BLDC ...
406 views

Confusion with applying KCL to three phase delta connection

Below is a 3-phase delta connected for balanced loads Z: Since phase to phase voltages(voltage across loads) have 120 degrees phase differences and since the loads have the same impedance we can ...
23 views

LTspice Model Stopped Working

Tried to model an equivalent circuit for a 3-phase TN-S system to model inrush behaveour. Was working for a while, and now nothing beyond the "Power Cable". Probably an obvious reason, but ...
96k 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 ...
83 views

Simple wireless power transfer circuit question

source: https://circuitdigest.com/electronic-circuits/simple-wireless-power-transmission-circuit-diagram Above circuit is the very simple wireless power transfer circuit, but I could not find any ...
12 views

Testing a 3-phase ev charger on an 1-3 frequency regulator

Im currently working in an office environment developing a system to communicate over rs485 Modbus with an 3 phase EV charger. Due to the location it is not possible to get three phase power. However ...
22k views

How to connect a three-phase motor

I am trying to fix an old three-phase drill. The motor has 3 wires coming out of it, which connect to the three phases. Connecting it to the power does nothing, and so I tested it with a multimeter, ...
83 views

Current Transformer in power meter

How to measure the total power in a 3 phase electrical system with one current transformer?
807 views

12VDC to 3 Phase 400V

In order top prevent my seldom used deep well pump (3 Phase, 400V) I plan to daily spin it up for a few seconds. Where the pump is located, the is no power supply (I operate the pump using a ...
166 views

Connecting DC Common Node (Ground) to Three Phase Neutral

I know I shouldn't. But I just wanted to ask due to a specific requirement. I also searched the forum but couldn't find any similar question. Please give me a link if there's any. I'm asked to modify ...
233 views

3 Phase Input Power

I have a 3 phase switching power supply that I am trying to calculate the maximum input power. It is hooked up to a 3-phase, 277/480 VAC power source. The sticker on the power supply says: "INPUT : ...
142 views

Calculating heat generated by resistance wire on 3 phase current

I am designing a heating element consisting of resistance wires coiled around a tube to heat water flowing in the tube. All three heating elements (loads) will have the same resistance and will be ...
110 views

For induction motors, would one expect harmonics to be different between Delta and Y stator windings?

Given two induction motors with the only difference being that one is wound delta, the other Y, would I expect to see a different behavior if the source is a three phase voltage with harmonics?
62 views

Do data centers use single phase or 3 phase to power their infrastructure?

3 phase is more efficient than single phase for converting AC to DC; since after rectification stage the signal requires less regulation. Do some data centers use 3 phase power to take advantage of ...
330 views

DIY 3-phase fast linear actuator

I have a need for a FAST linear actuator of which I may control position and speed reliably. I have already been looking into pnuematics, however it does not seem that this will fit my needs (I am ...
135 views

How can I tell if my banana fits in the banana hole?

Are all banana plugs the same? Can I use these Fluke brand banana plugs and plug them in to this Extech brand phase rotation tester? Will they fit? What defines banana plugs anyway? Is there an ISO ...
48 views

Need help selecting the right speed controller for a 3-phase AC motor [closed]

This a three-phase single-volt 5-HP AC motor salvaged from a treadmill with a busted controller board. The goal is to salvage the treadmill. Originally I was trying to repair the controller board. I'...
120 views

Drawing power from only one phase of a 3 phase alternator

Note: I am busy learning about 3 phase alternators. A lot of my understanding is theory so I'm running through scenario's for better understanding. Scenario: Lets say we have a 2KW-220V-50Hz 3 phase ...
4k 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,...
4k views

Need help identifying wires on 3-phase single-volt AC motor (6 leads)

I'm far from an electrician. Just a guy trying to get some new life out of an existing piece of machinery. See the image below, this 5HP motor comes from a heavy duty commercial treadmill. Based on ...
44 views

Why were the phase currents taken instead of voltage as inputs in the space vector moduation method?

Why is it that the currents (ia,ib,ic) are taken as inputs, instead of voltages (va,vb,vc), when at the end, you need to create 3 phase stator voltages for the rotor to catch up with?
3k 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 ...
402 views

BLDC phase voltage wave form

I am measuring the phase voltage of a BLDC motor as shown in the figure below. As the motor doesn't have neutral point, a virtual neutral point(VN) is created by the resistor network and three-phase ...
43 views

Unsure if motor starter (contactor + overload) is needed instead of normal solid state relay

I am designing a system with several pumps ranging from 0.5 to 1.5 HP (all single phase) and am unsure of what kind of circuitry I need. I researched different motor contactors and overloads I could ...
128 views

Does using electronics with poor power factor affect the pulse power capability of a generator rated for a certain KVA?

The situation is such: There is a multi-pole, three-phase, permanent magnet generator (rated for 100 KVA, let's say) that feeds into a simple diode rectifier with a capacitive/DC Voltage load (...
54 views

What governs the output voltage of a three-phase generator?

If you have a three-phase generator (or motor run as a generator), what part of it governs the output voltage? For example the speed at which you rotate the shaft governs the output frequency, but ...
73 views

Is it safe to bundle together 380V cable + 24V signal cable + network cable?

I have the following cables between two machines: 380V 3-phase power cable 24V signal cable EtherCAT cable I would like to create an interface using a modular connector such as the one in the ...
161 views

Generated current in a $3\times450$ VAC $60$ Hz $1150$ kVA generator

Let's say I've a $3\times450$ VAC $60$ Hz $1150$ kVA generator. How much current will there be generated when it runs at maximum capacity? MY WORK: The total Active power over a three-fase ...
35 views

Finding the power dissipation in a wye-connection given resistors

The problem that I'm attempting to solve is the following: Three 1000 Ī© resistors are connected in Y to a 200-Vac line. The power dissipation of the Y combination would be _____W. a. 42 b. 41 c. 40 d....
13k views

Is it possible to convert 3 Phase 220V to 110V without use of a transformer?

I am living in an area where line voltage is 220V. If I have access to all 3 phases, is it possible to create a "socket" with output voltage of ~110V, without use of a transformer? This is primarily a ...
48 views

Shoot through problem in 3-phase BLDC controller circuit

I have designed a 3-phase controller for a BLDC motor. I am checking one side of the bridge with a Pico-scope for shoot through. The wave-forms below are indicating that i am getting shoot through, ...