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Questions tagged [three-phase]

AC power with three legs run 120 degrees out of phase

-3
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0answers
24 views

Phase shift between the winding of a three winding transformer [on hold]

What is the phase shift of the output voltage of a three phase three winding transformer connected as follows: Primary: Delta1. Secondary: Delta11. Tertiary:Wye. Is there a 15 degrees phase shift ...
0
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0answers
55 views

Circuit for Neutral point of 3-Phase mains

I wonder if the 'Neutral Point' as mentioned in the attached image is correctly labeled or not? Is there any mistake in this 3-phase circuit design? Edit 1: Also it looks like the 'Neutral point' is ...
1
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0answers
44 views

24V, 3 Phase BDCM Controller Schematic

This may seem like a dumb question, but does anyone have a schematic for a BDCM controller. All I seem to be able to find are partial schematics or schematics that include a micro controller. My ...
0
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1answer
47 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 ...
0
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1answer
55 views

Two level Inverter [closed]

What thing determines a 2-level and 3-level Inverter as in the diagram? edit: Level is as in 'voltage level'. I have found following good link that explains it. http://www.elkraft.ntnu.no/~richardl/...
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0answers
41 views

3 Phase vs line to line [duplicate]

Say I have the following three phase wye configuration: Source Let’s also assume that all three loads have the same constant resistance, therefore in this case the system is balanced and the neutral ...
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0answers
103 views

IR2301 HO output staying on too long

I'm trying to make a 3 phase motor controller with IR2301 and IRFPC50 MOSFET. I connected everything according to IR2301 datasheet. For capacitors I’m using 10 uF (between VCC and GND) and 2.2uF (...
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1answer
42 views

SPWM vs SVPWM implementation [duplicate]

I am learning various control techniques for 3-Phase ACIMs. So far I have understood about the SPWM implementation.. in which we save Sin values in a LUT and then modulate the duty-cycle of PWM wave ...
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2answers
74 views

SPWM vs 6-step PWM vs SVMPWM

While learning 3-Phase scalar control of ACIM using STM32F407 MCU I could not clearly understand the diffrence between the following terms: 1. SPWM 2. 6-step PWM 3. SVMPWM How do they differ from ...
0
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1answer
82 views

3-phase motor (hi-hp) fails on start, insulation was > 500 megohms. WHY? [closed]

This is a common situation in industry where the 3-phase motor has a resistive reactance fault (as small as 1% unbalance) PRIOR to start. Insulation has been subject to excessive heating but meets ...
0
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1answer
21 views

Phase or Line V/F Control for ACIM

I am trying to implement V/F control for 3 phase ACIM using STM32F407 MCU. I am using 6 Complementary outputs of its Adv. Timer 1, Center aligned 256-points PWM waveform. The DC Bus voltage is 600 VDC....
0
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1answer
31 views

how to get the line voltage of 3 phase delta circuit with power factor known at first?

In the following picture, it shows that a black box at right. the circuit inside the black box is a 3 phase load balanced delta connection circuit. the line voltage of it is 500V and the power factor ...
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1answer
55 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 ...
1
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1answer
50 views

Is it possible to design a three-phase delta generator only with two generators? [closed]

I've always seen 3 generators in a three-phase generator, but this question came to my mind. I've tried to add an element instead of the third generator, although with no result. I hope someone can ...
0
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1answer
18 views

Balanced delta source to Wye source by considering magnitude only is ok?

I read and derived formulas for balanced delta source to Wye source; it is given by Vy = Vd / sqrt(3)<30 but in some places I see people only dividing by sqrt(3) for conversions are keeping angle 0,...
2
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1answer
36 views

Discrete simulation of 3-phase inductive load

I would like to make a discrete time simulation of a 3 phase inductive load but I am struggling with the problem. I have this Y configuration in mind. I'd like to simulate each current and Vn, given ...
1
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1answer
51 views

3 phase - Unbalanced loads from line to line

In the case of a 3 phase wye unbalanced configuration such as the following: we can compute the amount of current going through the neutral wire using geometry, in this case it is \$\sqrt{(\cos(150^{\...
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2answers
48 views

Poles of induction motor rotor

For a three phase squirrel cage induction motor (IM,) we can have 2 or 4 or 6 etc. pole pairs on its stator and when these stator windings are energized by 3 phase mains supply then we get a rotating ...
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2answers
32 views

Induction Motor Poles and Drive Configuration

If an IM is driven by a VVVF drive and the poles of the motor do not match with the drive configs.. eg., IM is 4 poles but the drive setting is 2 poles.. or the other way around.. then can it create a ...
0
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1answer
60 views

Wiring a 2 pole three-phase DB motor to a VFD

Hello everyone this is my first time posting here so forgive me if my post seems a little choppy. So my dilemma is trying to hook up a 2 pole three-phase DB motor rated at 230 X 3. I did a fair amount ...
0
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1answer
37 views

motor slip vs rotational speed

In Induction motor theory the term slip is used as normalized relative speed of the rotor to the synchronous speed and it depends on the physical rotational speed of the rotor. Is there any special ...
0
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1answer
46 views

3 Phase calculations

I have 3-phase utility mains power supply whose phase voltage is 220 V, 50 Hz. I keep getting confused about various calculations of the 3-phase mains as follows: Formula for the line voltage. ...
1
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1answer
104 views

What is the practical use of Laplace Transform?

I am trying to understand the electrical model of 3-phase Induction Model. The rotor of the motor is modeled as a variable resistor in s-domain. I fail to understand how that works practically. Can ...
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3answers
101 views

What is line to line voltage supposed to meter at?

I'm pretty new to this but I know that in three phase power, when I'm metering line to line its usually at 208V, but I've been told that line to line meters at 240V. I don't know what would cause for ...
0
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0answers
30 views

Three-phase circuit with line impedance

I'm having some trouble with the first part of an exercise. If I only have V1, and Zl, how can I find what the line voltage V2 is equal to? So that, then I could calculate the phase currents A1,A2,A3....
1
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2answers
107 views

Modelling 3-phase induction motor and filter for inverter output in LTspice

I am designing an inverter in Ltspice and am looking to have a simple circuit to represent the motor load and filter out the PWM harmonics in order to obtain outputs. The motor characteristics are: ...
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2answers
59 views

How to maintain a stable voltage on a Wind Turbine for Inverter

I'm doing some experiments on a wind turbine in my spare time. At the moment, my system runs well and I can measure good output values from my generator. For example: 38V @18Hz at 30 RPM 97V @37Hz ...
0
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1answer
62 views

What should be switching voltage rating of relay in a 380VAC 3 phase system?

I am hooking up a system where there is 2 sources of power available. One source is the grid power, and the other is a generator. The grid provides me with 3-phase 380VAC with a neutral wire; and on ...
0
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1answer
31 views

What is the difference between a rupture and the neutral conductor not existing from the start in star three phased system?

I have a pretty basic question. In three phased systems, I know that if the loads are equal, the neutal conductor has no role and can be removed, my question concerns unequal loads. My question is, ...
1
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1answer
240 views

How can 400V & 690V on e-motors result in the same power

Forgive my ignorance, but how can two 3-phase ratings on the same motor result in the same output power? The one I have is rated for 0.7kW in triangle for both 400V and 690V.
0
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1answer
50 views

Proper supply wiring for CNC router 4.1 kW 3Φ motor and 120 V accessories?

I'm building a CNC router table that has a three-phase 220 V spindle motor, and 120 V computer (and accessories). The spindle's nameplate: As you can see it tops out at 20.3 A @ 220 V. The VFD’s (...
1
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1answer
128 views

Line voltage and phase voltage question

​ In the question, why couldn't I just find Line current from Line Voltage? Is not Line Current=Line Voltage/Impedance? I know line voltage and line current aren't in phase, that the angle between ...
1
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0answers
73 views

How do I bring back to life a very un-excited 3phase 10kVa alternator

We are restoring a water mill and have recently got our 2 wheels turning once more. One of them is connected to an existing 3phase 10KVa alternator which although a little old seems to be in good ...
1
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4answers
775 views

3-phase 380 V to 3-phase 230 V

I have a portable bearing heater which works with 3-phase 230 V power supply. My power supply is 3-phase 380 V. Is there any way to convert the 3-phase 380 V to 3-phase 230 V? ...
1
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2answers
83 views

What is meant by the Sending end and Receiving end in 3 phase electrical circuits?

I do not understand the what sending or receiving end means in 3 phase circuit analysis. Aside: Also I am struggling to understand 3-phase just in general with respect to circuit analysis so if there ...
0
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3answers
186 views

Are three-phase contactors rated per pole or in total?

Are three-phase contactors rated per pole or in total? For example, have a look at this datasheet for a random three-phase contactor: datasheet In the datasheet it says that for AC-3 loads (1) the ...
2
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1answer
93 views

How is power out one side of 220 only - Problem is with incoming 3-phase. But how?

[EDIT] Can someone who understands what I wrote explain this? [EDIT 2] Sorry I didn't say I'm in the USA, the power is 110/220vac 60Hz. The input to the main power transformer is 3-phase, underground,...
0
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1answer
24 views

Can a DFIG operate in a synchronous speed?

A DFIG can operate in both sub and super synchronous modes. Can a DFIG also operate (stable) in a synchronous speed? If so, would the rotor current (as decided by IGBT switching) be DC since the rotor ...
0
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1answer
45 views

Reactive Power in grid side converter for Doubly fed induction generator

Does the grid side converter in a DFIG absorb/provide reactive power or is it reactive neutral? Also, what can we say about reactive power exchange in the rotor side converter?
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1answer
43 views

What are the d and q axes for induction machine?

What are the d and q axes for an induction machine (physical meaning)? I understand them for a synchronous machine but how are they defined for an IM?
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2answers
127 views

When tapping single phase power from a 3 phase service, how much power can safely be drawn?

I'm setting up a piece of lab equipment that needs 220v-260v to operate properly. The room it's located in has a a 480v 3-Phase service, in the form of a California Standard 50Amp twist-lock connector....
0
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1answer
56 views

“3 phase” Type of winding I am not aware of, help? not wye or delta, maybe eFed up generator?

I bought a few 30 watt 3 phase motor/generators in supposedly delta configuration from a ali express. the motor did have only 3 wires coming out, plus the manual stating it, I am pretty sure this was ...
0
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1answer
43 views

Calculating power with three phase?

I can't seem to find the answer I'm looking for, or perhaps I'm just really not understanding what I've read. I'm just confused. So, I'm a college student in a Theatre Production program and an ...
1
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2answers
91 views

Meggering Three Phase Motor (Phase-GND, Phase-Neutral, GND-Neutral)

When meggering a three phase motor, could someone please help me understand the values we would expect to see for a motor with no insulation or ground faults. From my understanding: Phase-GND: ...
2
votes
1answer
456 views

Instantaneous vector sum of three phases 120 apart is not zero?

Vector sum of equal 3 phases 120 degree apart is zero and serves as a neutral. However, while drawing instantaneous vectors of the three phases, they summed up all together to give a vector. I have ...
1
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0answers
51 views

Is there a cost savings associated with 3 phase power at the same device power requirement (kW)?

I am a Mechanical Engineer looking into purchasing an annealing furnace and have seen that some operate on single phase power while some operate on 3 phase power. I've done some research and have seen ...
1
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1answer
229 views

MOSFET H-Bridge Design - Capacitor/Diode/Resistor Selection

welcome to my first post! I am designing a small 3-phase Brushless DC Electronic Speed Controller (ESC). The design utilizes 3 half bridges and a FAN7388 driver IC. The FAN7388 datasheet has a ...
0
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1answer
251 views

Why use a star or delta connection instead of having a second output

I am winding my own small three phase ac alternator and have learned about star and delta connections. Should I use 2 three phase rectifiers to turn the current to DC or only one with a star ...
2
votes
1answer
53 views

3 Phase “Black Box” Load

I'm doing a few basic load calculations on a 3 phase circuit at work and I stumbled on a concept I'm not sure how to proceed. Let's say you have a 3 phase load and it is basically a black box. For ...
0
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1answer
86 views

480v motor, running like a bat out of hell.

I have a 480v motor that is connected to an auger. When the auger fills up, the torque from the motor continues to drive it and then just snaps the shaft clean in half. I am looking to build ...