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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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Can one connect 2 or more DC motors of same or different excitations in series or parallel combination,and how does it work [closed]

I am trying to understand DC motors,but i had this doubt throughout the machines course. .How does speed and torques and speed gets affected(major query)
NISHANT DUBEY's user avatar
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1 answer
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Do eddy currents in a rotor core of an induction motor create torque proportional to the coil current of a squirrel cage?

In a rotor of an induction motor, the core plates and wire coil conductors have non-zero thicknesses. Therefore, eddy currents non-zero too. And they approximately proportional to the coil current of ...
Imyaf's user avatar
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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 ...
aulven's user avatar
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Rotor types in Synchronous Reluctance Motor

I am doing research on Syncrhonous Reluctance Motor (SynRM) and the rotor used in it. I am a bit confused in their rotor types. Now according to Google, the rotor types do consists Salient Poles Rotor ...
Muhammad Ahmad's user avatar
3 votes
4 answers
864 views

Is copper loss present in the winding of an autotransformer?

Since the autotransformer transfers power conductively in addition to through its magnetic field, does its winding also cause loss of electric power in the form of copper losses? It seems to me that a ...
Dwqae's user avatar
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Reluctance concept

I would like to appeal question, where the correct answer was given as option (B) 'Cross-sectional area.' However, I believe that option (D) 'Permeance' is also inversely proportional to reluctance. ...
Dragnovith's user avatar
2 votes
1 answer
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Magnetic interaction between resolver & motor windings?

Scenario: Synchronous electric motor whose rotor position is measured by a resolver. Won't the magnetic field created by the motor stator & rotor, link with the primary & secondary windings ...
DarkMIR4GE's user avatar
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203 views

DC motor operation at no load

I was solving a DC shunt motor question where no load is specified to: Speed=1000 rpm Rated armature current=3.33 A Rated voltage=230 V And Ra=0.3 Rsh=160 Line current = 40 A (at full current) were ...
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Best switching topology for axial stator with rotating field

The idea is to have a stator with coils driven by AC current not switched with DC as is done in most cases. On top of that I need the field to physically rotate around with the rotor. This essentially ...
Girts's user avatar
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How to model the dc link voltage dynamic of the inverter fed induction machine drive in braking mode?

I have been attempting to find the differential equation describing the dynamic of the dc link voltage of the induction machine based electric drive in braking mode. I have started with the energy ...
Steve's user avatar
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Can we go beyond rated terminal voltage at no load with a synchronous generator?

A synchronous generator is made to rotate at constant speed and it only has a voltmeter connected to its terminals between line and neutral. In this scenario the terminal voltage will be equal to the ...
dRIFT sPEED's user avatar
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What does rated voltage of synchronous machine mean?

What does 'rated voltage' we see written on the name plate of synchronous machines mean? Is it the generated voltage or terminal voltage? By generated voltage I mean the EMF induced in the machine and ...
dRIFT sPEED's user avatar
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3 answers
255 views

Torque on generator due to reactive power

Since reactive power goes back and forth from load to generator, so when reactive power goes from load to generator this should manifest as torque that's exerted on the rotor right? (like that of a ...
diode's user avatar
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Electric Torque Equation of DFIG Wind Turbine

I go through the several books and research paper related with DFIG wind Turbine. There is some confusion regarding these two equations. Can any one clarifies this confusion? In one place Te = Kopt * ...
aman2909's user avatar
1 vote
1 answer
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Battery for a 24 V, 200W or 250W DC motor

I am trying to build an electric scooter and have decided on either a 200 or a 250 W DC motor. However, I’m struggling to choose a battery that would be sufficient for these motors. I want the scooter ...
Eray's user avatar
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7 votes
2 answers
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In an electric machine, does the force act on the copper conductors or on the iron and why?

My question arises from the following reasoning: Starting from the basic explanation that a force acts on a current-carrying conductor in a magnetic field, I realized that, more concretely in ...
PortaL's user avatar
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I used another power adapter for my soda machine [closed]

I have a soda machine that was working perfectly until I decided to use another adapter just to check if it still worked. Now the soda machine is not working anymore, please help! This is the ...
Juan Olaya's user avatar
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1 answer
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Importance of ADC Speed for Accelerator Pedal Position Sensor (APPS)

We are building a electric vehicle and need an accelerator pedal position system. We have the circuit designed as shown below. When simulating our circuit, the ADC speed of the Arduino Uno seemed slow....
Kalamakra's user avatar
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Mapping geometric to electric parameters for a PMSM machine

I am looking at a PMSM machine described by the following equations: $$\frac{di_d}{dt} = \frac{\omega_e L_q}{L_d}i_q - \frac{R_s}{L_d}i_d + \frac{u_d}{L_d}$$ $$\frac{di_q}{dt} = -\frac{\omega_e (...
Josef's user avatar
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2 votes
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How to calculate the parameters of the equivalent circuit from the no-load measurement of the induction motor?

I would like to determine the values of the parameters of the magnetizing branch of the equivalent circuit of the induction motor based on the no-load measurement. Based on the Electric Motor Control ...
Steve's user avatar
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How to calculate torque of a three-phase induction motor?

I have a three-phase induction machine with following nameplate data: \$V_{s_n}=\frac{425}{\sqrt{3}}\,\mathrm{V}\$ - effective value of the phase voltage, \$f_n=70\,\mathrm{Hz}\$ - nominal frequency, \...
Steve's user avatar
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1 vote
0 answers
850 views

Number of turns needed to rewind a 4-pole motor as 2-pole

I'm wishing to rewind a 4-pole, 1/2 cv motor as a 2-pole motor for the same voltage rating. Its stator has 32 slots, and the main winding looks like this: It's a concentric winding, made of 4 ...
user2934303's user avatar
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2 answers
65 views

Electric panel heater to smart [closed]

I just bought a house that comes with these panels for heating. The panel has a timer but I’d like to explore if there is any smart option. The option I initially checked is those smart WiFi plug, but ...
Geo Koro's user avatar
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1 answer
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Why is the output voltage of an electric generator limited to 25 kV?

I'm currently studying electrical machines, and reading the book I found the following statement: The output voltage of an electric generator is usually limited to 25 kV due to physical ...
grex1997's user avatar
1 vote
1 answer
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Nodal admittance matrix of a winding

I have a question concerning the nodal admittance matrix of a winding that has n turns. If each turn of the winding had its own model, is it possible to consider my winding a n-port network?
Wallflower's user avatar
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3 answers
216 views

Can a rheostat (as an alternative to a relay) act as the correction unit in a thermostatically controlled electric heater?

I was studying about the various elements present in a thermostatically controlled electric heater control system. While I agree that a relay can be used to correct the output temperature from a ...
Sheraz Malik's user avatar
1 vote
0 answers
408 views

How to calculate total power required for an electric vehicle (ebike) design?

I wanted to design an ebike with good enough specs to satisfy my requirements, my first consideration was the power required to move the bike at my required speed and from there I can choose a motor. ...
AhmedH2O's user avatar
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-1 votes
2 answers
48 views

How do I write first order numerical method for finding power? [closed]

I'm new in this just taking the lectures on YouTube according to this, a self learner you can say I'm stuck in a problem of how to write numerical method for finding power of motor in the given set of ...
Uzair Kabeer's user avatar
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2 answers
114 views

A question regarding reactive power

Why does the production of reactive power not require extra fuel unlike active/real power?
Jirhs Kumar 's user avatar
-2 votes
2 answers
158 views

Importance of power factor [closed]

I understand the difference between reactive power, but why is power factor so important? A system with low PF draws more current; well wouldn't a larger load, be it resistive or reactive, draw a ...
Jirhs Kumar 's user avatar
1 vote
1 answer
137 views

Armature Winding

This might seem like a silly question, buy why aren't armature windings usually done in a simple manner as shown in the image, why does it have to be more complicated such as lap winding etc?
Jirhs Kumar 's user avatar
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2 answers
227 views

Why would a motor have 100kW in 90kW out?

I might have phrased my question wrong but our lecturer asked us a question about why a motor (or generator I am not sure) would have 100kW in and 90kW out. He proceeded with saying that it had ...
Kalamakra's user avatar
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1 vote
0 answers
74 views

What's the per phase equivalent circuit of induction motor with asymmetric windings?

We know that there's T equivalent circuit and inverse Γ-equivalent circuit for 3 phase induction motor(IM). When the IM is operating under normal situation, the windings are symmetrical, so all 3 ...
user11004178's user avatar
1 vote
0 answers
60 views

Mechanic and electric power after imbalance in power system?

After a power imbalance (for example a generator disconnection) in the electric grid, generation and consumption are not equal. This causes a dynamic transient in generators described by the Swing ...
Samuele Benito Di Gioia's user avatar
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1 answer
269 views

Which problem occurs with large synchronous motors in the event of high starting current?

So I was performing a test just recently with a synchronous motor at my school, and the teacher said that starting synchronous motors with a high starting current would cause problems to the machine. ...
ElonTusk1312's user avatar
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1 answer
123 views

Relative Permeability of Rotor

I am working on an example question from a electric machinery textbook. The question provides a simplified version of rotor and stator as shown in the picture below (please excuse me for the poor ...
john kim's user avatar
1 vote
1 answer
49 views

Need some help with design for reduced friction acceleration of a ferromagnetic mass through a barrel

I would like to levitate (by that I mean just enough to not make contact with the surface of the barrel) and accelerate a ferromagnetic mass along a barrel of a certain length. I have a few questions ...
ICRed's user avatar
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0 answers
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Identifying the components of an electric motor

I need to calculate the magnetic field in the airgap of this electrical motor (also other things such as torque) but I'm having difficulty identifying its components (airgap, rotor and its nucleus, ...
bebewow's user avatar
1 vote
1 answer
131 views

Force of attraction on the actuator arm

An actuator system is shown below. All dimensions are in centimeters. The magnetic material is cast steel, whose magnetization characteristic is shown in Fig. 1.7. The magnetic core and air gap have a ...
Luz0000's user avatar
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1 vote
2 answers
78 views

Is there any way to estimate transformer's estimated remaining lifetime without testing the oil (or degree of polymerization)?

The common parameter for transformer health monitoring is testing the oil and sediments (N.B., there might be others I don't know). The insulating strength of oil is decreased due to faults, overload, ...
Sadat Rafi's user avatar
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0 answers
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Standard equation for delivered power from synchronous generator wrong for fractional kW machines?

When synchronous machines get to a certain size (in the \$MW\hspace{-0.8mm}s\$) the armature resistance is a lot smaller than the synchronous reactance, \$R_A << X_s\$, because of this \$R_A\$ ...
JMy's user avatar
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0 votes
1 answer
184 views

Three phase induction motor connected in single phase power system

I'm trying to figure out an experiment in a lab that we did with a three phase motor connected in a single phase power supply. The schematic is as below: I measured all currents in the motor windings,...
João Marques's user avatar
0 votes
1 answer
212 views

Can someone verify my understanding of induction motors?

Here's my understanding of the induction motor, it would be really helpful if someone can verify it. 3 phase AC supply given to stator, sets up an rotating magnetic field (RMF,) \$ B \$ (discussing ...
Aravindh Vasu's user avatar
1 vote
1 answer
75 views

Oversized electrical motor, synchronous, vs asynchronous

I know that a oversized motor would consume more energy than a well sized one, and in a low load scenario it will present a lower power factor than a well-sized one too. My question is, what is the ...
user14398375's user avatar
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0 answers
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Exciting the rotor and stator of a slip ring induction motor at different frequencies, will it develope torque?

I came across this question as I was preparing for an exam, I am unable to understand the theory behind it. The textbook says the motor can run a 600 and 2400 rpm but gives no explanation. Could ...
User's user avatar
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0 answers
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Is it viable to short pitch different windings by different degrees of short pitching in the same synchronous generator?

In the design of a synchronous generator one can chose to eliminate or reduce harmonics at the expense of emf. The pitch factor \$K_p = \cos(\alpha/2)\$, which is always less than or equal to 1, ...
JMy's user avatar
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0 votes
2 answers
2k views

What is the difference between applied voltage and induced voltage at primary side of transformer specifically?

I am not able to understand difference between applied voltage and induced voltage. Whenever voltage is applied at primary side of transformer there will be primary current producing flux using ...
Jonathan's user avatar
-2 votes
2 answers
664 views

Is there non conductive solder?

I am making a project in my university and I really need to find a way to glue back together two blocks of the stator (part of an electric motor). As you probably know the sator is composed of sheets ...
jmml's user avatar
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0 votes
1 answer
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Why can't we increase diameter of induction motors as we can do in axial flux motors?

Axial flux motors have high torque to weight ratio. One of the reason is that it has larger diameter. which means since T=F*r . if r-->radius increases torque increases. More specifically I read it ...
Yogita's user avatar
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2 votes
0 answers
241 views

How does mutual flux in a synchronous generator remain constant like in a transformer?

Given is the flux per pole of of a synchronous generator 1)Is it field/rotor flux per pole ? 2)The generated emf per phase is given by E=4.44Nfφ where φ is the flux per pole But from transformers, we ...
Nigel Goveas's user avatar

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