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Questions tagged [rotor]

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0answers
19 views

Flux and inductance in simple motor

This is the front view of a cylindrical motor of depth (or height) \$D\$. There are three windings: \$\alpha\$ (stator), \$\beta\$ (stator) and \$\gamma\$ (rotor): Considering the core to be of ...
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1answer
122 views

What type of motor is this? (photo included)

I want to make this motor work, but I can't understand what type this is. I supplied 5V DC to the terminals, but it just kept buzzing and the coils were energized. It also had some kind of circuit, ...
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1answer
111 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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1answer
28 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 ...
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3answers
75 views

Apart from speed, do VSD's also alter current?

As I know it, a VSD alters the frequency to change the speed of a motor. I also understand that since the back emf of the rotor is directly proportional to the speed of the rotor, the slower the motor ...
2
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1answer
217 views

Working of a Doubly-Fed Induction generator (DFIG) in wind turbines

I am unable to understand how a Doubly-Fed Induction generator works (in Wind Energy conversion system)? I do not understand how the reactive power fed into the stator interacts with the rotor so as ...
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0answers
41 views

PM Generator magnet and stator relation

I am designing a 3 phase axial flux permanent magnet generator. Howewer, I can not find reference or study of the optimal size of slot and coil, in relation to the magnet. I am adding a picture for ...
0
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1answer
54 views

Why the rotor core losses are very tiny compared to the stator core losses in an induction motor?

Book says rotor mostly runs at speed near to synchronous due to which the relative velocity between rotor and stator magnetic field is very less. Correspondingly making rotor core losses tiny and ...
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3answers
349 views

Why rotor copper loss in induction motor doesn't change with slip

Why air gap power is consumed in R2/s but rotor copper power loss only in R2? Transformer Equivalent circuit of Induction motor: ...
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0answers
49 views

EMF - DC Permanent Magnet Motor

I am using FEMM to design a dc permanent magnet rotor. I am trying to calculate the EMF that is induced to the rotor. Since each coil has a different position, the induced emf will be different. In ...
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4answers
3k views

Why is slip necessary in an Induction motor?

Why should the rotor of a 3-phase induction motor not rotate at synchronous speed?
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3answers
6k views

Finding number of pole pairs in a BLDC motor

I have a 3phase CDROM BLDC motor for which I don't have any datasheet. How can I find out the number of pole pair in the motor? Hint:-With a magnet, I could check that there are some N and S poles in ...
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1answer
299 views

Can I coil directly onto the iron cores of a stator for a basic generator?

I am constructing a very basic miniature generator (25mm diameter), the rotor has 8 bar magnets, and there will be the same number of coils, wired appropriately, in the stator. . I understand that ...
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0answers
55 views

Describe this type of rotor from a three phase induction motor?

After CNC machining the rotor, to expose the outer surface of the silicon iron, this proves to be exactly the same as the inner surface was (the one facing the core).Just plain electric iron rings ...
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3answers
68 views

IC that measures RPM mounted on rotor without magnetic field [closed]

Does this chip exist, there only seem to be hall sensors?
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1answer
395 views

Relating Hall sensor outputs to absolute rotor position (Which combination corresponds to which angle)

I have a working 6-step BLDC commutation which works based on the Hall effect sensor outputs. I would like to apply the same code to another motor, which doesnt have Hall sensors but an absolute rotor ...
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0answers
131 views

Why does excitation voltage lie on the quadrature axis in a salient pole synchronous machine?

I am having a hard time rationalizing why the excitation voltage (Ef) always lies on the q-axis. My understanding of salient machine is that current has been broken down into d-axis and q-axis ...
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1answer
2k views

Why would a rotor get stuck on the side of the stator when the induction motor is turned on, and how to fix it? [closed]

My big fan stopped working, so I decided to dismantle it and check what's wrong with it. The problem lies in a faulty induction motor. I opened it and found out that I can easily turn the rotor ...
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2answers
1k views

what is the transformation ratio of squirrel cage Machine? [closed]

typically Induction machine also called rotating transformer so what is the ratio of stator numbers of turns to rotor number of turns (from the design point of view i.e we can't directly measure ...
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0answers
198 views

Laminations for brushless rotor?

I'm planning to build a brushless DC inrunner motor, with permanent magnets glued to the rotor. I know the stator needs to be made of laminations of electrical steel to avoid eddy currents, but does ...
1
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1answer
100 views

Fine tuning PID controller for non-linear closed-loop system

I am having trouble getting my PID controller to be accurate over a range of values. My goal is to input a duty cycle for a PWM wave, which controls the speed of a fan rotor. The range of possible ...
5
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1answer
2k views

What is meant by front and back pitch of an armature winding?

I searched the internet for these definitions and found a common definition in all websites: Back Pitch- A coil advances on the back of the armature. This advancement is measured in terms of ...
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1answer
3k views

why the stator frame of a 3-phase generator is made up of cast iron?

I don't have a good knowledge of engineering materials, so please answer the following questions with reasons. Why is the stator frame of a 3-phase generator made up of cast iron? Why is the ...
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2answers
1k views

What happens if i rotated a DC motor's rotor?

a 3V DC motor. If i rotated its rotor at a constant RPM without any DC input, what will the output current be at the terminals? will it be a constant Sine wave or DC?
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1answer
2k views

Alternator shaft speed

I am running an alternator with an electric motor (variable speed), but I do not know the shaft speed. I would like to calculate it from voltage frequency. The rotor of the alternator has 12 poles (6 ...
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2answers
76 views

DC motor exception

What happens to our DC motor if we stop motion of the rotor with our hand while motor is active? Will the motor burn? Why, what is really happening in that situation?
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1answer
796 views

Rotor current paths and lamination in an induction motor

As far as I understood, the rotor currents circulate through the aluminium bars embedded inside steel laminations. But why do they use steel for laminations instead of an insulator if the the idea is ...
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3answers
2k views

Meaning of “with respect to rotor and stator”

In the following example, when it says “with respect to stator” and “with respect to rotor”, did they mean the rotor part of the synchronous generator in both cases? Example: The excitation field in ...
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2answers
216 views

Circuit of a Rotor on an Induction Motor

Here is an equivalent circuit of a rotor on an Induction motor: Can someone explain How do we arrive at this circuit? The rotor seems to be only a disc(made of a metal) with conductors embedded near ...
5
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2answers
2k views

How do I modify a DC electric generator to get the same power at a lower speed?

This will be a theoretical question. Suppose that I have a DC generator, and I'm getting 300VA power from it when it rotates at 2000rpm. I want to make it run at a lower speed of about 700rpm, and I ...
3
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2answers
3k views

Which parts of this rotor can be made out of plastic?

I'm asked to redesign a rotor, by making as much parts of it as possible out of plastic. The issue is its weight, we want to make it as light as possible. Especially the shaft & axis of it is the ...