Questions tagged [electric-machine]

Electrical Machines are Electro-Mechanical energy converters. They maybe classified into motors (electrical -> mechanical) and generators (mechanical -> electrical).

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40 views

How to set solver for control loop simulation?

I have been developing a simulation of the field oriented control of the three phase squirrel cage induction motor (control is oriented by the rotor flux). I have been using the Xcos which is an ...
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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 ...
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32 views

Why does wave winding not need a voltage equalizer?

I understand that lap winding needs a voltage equalizer to balance the voltage at different points. However, I could not understand why wave winding does not need one (according to the textbook "...
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36 views

Why duplex lap winding has twice as many current paths as simplex lap winding?

I found the statement of question on page 346 in the book "Electric Machinery Fundamentals, fifth edition" written by Stephen J. Chapman. When I searched for how duplex lap winding looks ...
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1answer
29 views

Explanation of v curve of sync machine

I am trying to understand the v curve of synchronous machine. Particularly, the point that changing field current can put the machine in leading or lagging mode. I am trying to get an explanation to ...
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119 views

Unexpected behavior of the Luenberger observer for three phase induction motor

I have been developing control software for three phase induction motor. The control software will implement the field oriented control algorithm. The considered algorithm is oriented to the rotor ...
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1answer
42 views

What electrode material can I use for electrical discharge machining? [closed]

Can I use an electrode made of melted soldering wire in electrical discharge machining (EDM) instead of copper or graphite? I think it is very easy for me to make electrode by using melted soldering ...
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38 views

what does nominal numbers of electrical machines mean

I got confused about rated numbers of generators and motors like rated voltage and rated power . I know nominal numbers of electrical machines are numbers which the machine is designed to operate but ...
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59 views

How to find rated voltage of a machine?

I am trying to understand what a rated voltage/current/power mean for a machine. when I google it, I typically get information on how to find it from nameplate, but I am trying to understand it ...
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163 views

What are the two sensors doing in the automatic bread production line? [closed]

I want to know what is the name of these 2 sensors and what function they perform Some of you were complaining about the picture quality. It is the highest quality image I can get. Also these sensors ...
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21 views

How to determine transform angle in field oriented control of three phase induction motor

I have been developing a control software for the field oriented control of the three phase induction motor. I have studied a lot of application notes and literature about this topic. Based on that I ...
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1answer
42 views

Rotor Current and Torque Producing Current in Induction Motor

Is rotor current of an Induction motor always same with torque producing current? In torque equation of Induction motor, there is also one factor called rotor power factor. if rotor current and torque ...
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40 views

Why stationary armature is preferred for commercial use

While reading a book on electrical machines, I found a point that says that for power generation, a stationary armature is the preferred type. If in any generator, there must be moving parts, why is ...
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37 views

Difference between reactive load and source?

Probably a silly question, but I am coming across terms like reactive power load and reactive power source in some articles in web. Does it matter if a reactive component is a source or load? Say ...
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26 views

Moment calculation for DC serial generator question

DC serial generator tag information : 9.25kW, 185V, 1500rpm . this is the table I have two solutions, which one might be right
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How can I find current in this Ward-Leonard system?

I was able to find only RPM in this question. How can I find the armature current?
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83 views

Transformer at no load [duplicate]

I have been reading about the working of transformers at "no load" condition, that is when no load is connected to secondary side of the transformer. I don't understand why the transformer still draws ...
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248 views

How does this old fan regulator circuit work?

I was on the lookout for an old fan regulator. I had heard that its power consumption was constant at all speeds. I could lay my hands on this 1970 regulator. It appears to be a transformer with ...
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1answer
93 views

Torque production in PMSM

First and foremost I have a question regarding the MMF distribution in a Motor produced by a single coil. I found a picture here: Why does the MMF not start at 0 at 0°? When I apply the $$NI=\int{H \...
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26 views

DC series machine

What is the different between electrical and mechanical torque? and How to find the mechanical torque if electrical torque is given?
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193 views

How was ceiling fan speed controlled before the invention (or availability) of Triac?

I am interested to know about the circuit diagram of the ceiling fan regulators of the old days (when Triacs were not available). I have searched on google but all of the results were related to SCR. ...
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1answer
30 views

SCC for Synchronous Generator Using Matlab

What should I put in ''Three-Phase Programmable Voltage Source'' block ?
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1answer
75 views

Induction motor starting torque and pull out torque

Recently I was doing some work on the induction motor where I found some general theory on starting speed torque curve of the induction motor. Where the theory is the starting torque will be 1.5x of ...
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88 views

What is meant by AT/cm in transformer?

In a problem related to transformer loss I have found a line "AT/cm for a flux density of 1.2 Wb/m^2 in iron to be 5" I've searched in google for 30 minutes about what is AT and how it is related to ...
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21 views

Formula for calculating the MMF and its harmonics of n-Phase PMSM with integral slot winding (slot per pole per phase =1 & 2)?

Data\Prerequisites: Integral slot winding full pitch winding Slot per pole per phase = 1 and 2 (two different possibilities) Number of phases : n = 3,4,5,6,7 Assume number of turns = N and current to ...
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1answer
25 views

What is all properties of orthogonal axis (dq) axis?

We know about the transformation between abc three phase to dq0 axis which is orthogonal. BUT I am confused about What is the added value and all properties of orthogonality for dq0 axis that help in ...
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187 views

Why do some motors have high rpm while other have low even though having same power consumption

I have seen a 500w motor which run on 1200 rpm but a 300w motor with over 10000rpm . I know using a gearbox can give required rpm or torque and torque is inversely proportion to speed but how can I ...
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In 1965 when Ivan Sutherland was testing the Vr machine, what was he viewing in the headset

Ivan Sutherland is an american inventor who invented virtual reality and the sketch, they recorded a video 55 years ago about him experiencing the headset, I always wondered what was he actually ...
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39 views

Voltage Difference Between Machine Laminations

Given a lamination stack that is exposed to a transient magnetic field, how can the potential difference between the individual laminations be determined? is there a rough rule of thumb that can be ...
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165 views

Does regenerative braking, using supercapacitors, really save fuel in the case of diesel city buses? [closed]

Does regenerative braking, using supercapacitors, really save fuel in the case of diesel city buses? A 10-ton diesel bus, fully loaded, that slows down, on average, from 30 km/h to 0 km/h each ...
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1answer
30 views

Which case count as leading PF in Salient plot generator?

In the figure above we can see the location of two armature currents. In case 1, \$I_{a1}\$ is leading \$Vt\$ (terminal voltage) but lagging \$E_f\$ (excitation voltage). In case 2, it is obvious that ...
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33 views

When do the positive sequence negative sequence, and zero sequence apprea?

I have analyzed three phases current in different cases, but I am still confused about some cases. Positive and Negative sequences are appeared but not the zero. Zero sequences is appeared, while ...
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103 views

Can someone tell me what this machine is? [closed]

It has two probes on two cables. I think it might be an xray machine but I can not be sure since there is no readable info on it. Can someone please identify it?
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1answer
264 views

Tesla model 3 motor

The Tesla's model 3 uses IPM-SRM motor in the rear drive. This motor is fed by AC supply OR DC supply? Is the motor's stator is of salient pole construction OR the same stator as of the induction ...
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1answer
120 views

Why earth pin in plug is larger than the other pin?

Why main line pin is not bigger ,the work of main line pin is more important than earth line? And the flow of electricity is also pass through main line and neutral pin then why earth pin is larger ...
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332 views

Why are the poles of the stator and rotor taken differently in the picture below?

The rotor and stator in the picture below have the same orientation of flux lines yet the are taken as opposite that is flux lines leaving the stator is taken as a South Pole while flux lines leaving ...
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1answer
62 views

Are the emissions to power electric cars really better for the environment than the emissions from petrol cars? [closed]

In my country most of the electricity is generated by coal which is then in turn used to power electric cars, which I don’t think is to good for the atmosphere, is there any prof that this is better ...
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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?
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1answer
106 views

Are permanent-magnet motors equally (in)efficient as motors vs. as generators?

Given a permanent-magnet motor with an efficiency of 80% that converts 100W electrical input power into 80W mechanical output power, would the motor have the same efficiency if used as a generator? ...
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AVR Excitation System and Generator in SimuLink

I am designing in simulink cooperation of synchronous machines with the grid. The main blocks are Excitation System which is AVR [link1] and Synchronous Machine [link2]. On the site we can find "...
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2answers
64 views

In 3 phase induction motor how many phase will be generated in wound type and squirrel cage rotor?

In 3 phase induction motor how many phase will be generated in wound type and squirrel cage rotor? If we consider a generator when the rotor rotates there will be voltage induced in every pole of ...
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1answer
53 views

Understanding of torque constant and efficiency of a permanent magnet motor from datasheet

I am trying to understand the efficiency of the following permanent magnet synchronous motor Motor Datasheet (note we are using the medium voltage model), and its relationship with the input voltages ...
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1answer
370 views

How brush shifting affects current distribution in dc machines?

I understand that how armature reaction causes neutral plane to shift by some angle . If brushes are placed along Geometrical Neutral Axis, then there'd be sparking during commutation as voltage ...
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1answer
24 views

Mean Free Path of Magnetic Core

I don't understand how they got the mean free paths (ls) of each leg. I know that I should be calculating the longest + the shortest paths and divide them by two, but I don't know HOW I should be ...
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If a high rpm motor is run at lower rpm, will it produce more torque?

I did the following calculations: Max current = 1.2A, Max voltage = 12V Then power = 14.4 watts = 0.019hp Rpm = HP * 5252 ÷ torque I need a torque to 2kgf-cm = 0.144 lb-ft Gives rpm= 698. Thus this ...
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132 views

why induction motor torque oscillating?

why when start induction motor the torque oscillate before become constant, like the following matlab torque simulation graph .
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26 views

Can torque angle of motor be positive?

For any motor text say that, the rotor field follows the stator field with a certain torque angle. And in case of generator, the stator field follows the rotor field with a negative load angle. The ...
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2answers
151 views

Hidrogen generator - electric problem

I made an Hidrogen generator (HHO) like YouTube : https://m.youtube.com/watch?v=zq8YMON9hjA&list=PLPCtNZjqSVUhWVzuxEkzlyrz1CatH8OiF&index=29&t=504s but , it does not working at all. ...
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110 views

Automotive alternator

I have been working on a project where so called Lundell alternator plays a crucial role. I haven't got any experience with this device sofar so I have decided to study some literature regarding this ...
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Electric brushed motor for electric car project

I am using a 24v 11amp 5700 rpm motor for a single seater car project. The problem is that when i am connecting the motor directly to the batteries without any throttle or control the vehicle shaft ...