What is Rotor: Definition and 148 Discussions

ROTOR was an elaborate air defence radar system built by the British Government in the early 1950s to counter possible attack by Soviet bombers. In order to get it operational as quickly as possible, it was initially made up primarily of WWII-era systems, notably the original Chain Home radars for the early warning role, and the AMES Type 7 for plotting and interception control. The system had a network of control stations, mostly built underground, and connected with an extensive telephone and telex network.
Work also began on a new microwave frequency radar to replace Chain Home in the 1957 time-frame. However, an experimental system known as Green Garlic was so successful that it began replacing Chain Home starting in 1954. In service, these proved so accurate that they could replace the Type 7 radars as well, and their greatly improved range meant that far fewer radars would be needed to provide coverage over the entire United Kingdom. This led to the Master Radar Stations that filled both early warning and ground controlled interception roles. The original ROTOR plans for 66 radars was repeatedly reduced, ultimately only requiring half that number of stations.
ROTOR called for the continual upgrading of the network over time, both the radars and the command and control systems. The introduction of the carcinotron radar jammer in the mid-1950s was a serious blow to these plans; a single aircraft carrying a carcinotron could jam the ROTOR radars so completely that they were rendered useless. At the same time, the introduction of the hydrogen bomb and ballistic missile greatly changed the nature of the strategic threat, and over time the idea of whole-country defence became untenable; the only way to defend against missile attacks was deterrence, and if that failed, interceptor aircraft and missiles would have no measurable effect on the eventual outcome.
ROTOR was initially to be replaced by a new network dedicated largely to defending the V-bomber force, the "1958 Plan". But even this role was eventually abandoned, leaving only the task of locating aircraft carrying jammers in order to keep the BMEWS radars free from interference and prevent a successful sneak attack. Such a system did not require a large number of radars nor country-wide coverage. To reduce the cost of this much smaller network, studies on integrating the military radars with civilian air traffic control led to the Linesman/Mediator system of only five primary stations. The original ROTOR was replaced by Linesman in stages, starting in 1967.
A similar expedient system in the United States was the Lashup Radar Network.

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  1. M

    Is there a resultant holding torque in the rotor?

    Hi, sorry for the title. I struggled to accurately describe my question in a short sentence. I'm trying to understand if there would be a holding torque or not in the following scenario. I'm referring to a motor which has a central stator and two permanent magnet rotor plates on either side...
  2. fluidistic

    Radiation E field of a rotor, can't get the result

    Homework Statement Two equal and opposite charges are attached to the ends of a rod of length s. The rod rotates counterclockwise at a speed ##\omega=ck##. The electric dipole moment of the system at ##t=0## is ##\vec p_0=qs\hat x##. Show that the electric field in the radiation zone is ##\vec...
  3. T

    How to calculate open rotor voltage?

    Homework Statement The AC power supply is connected to the stator terminals of the induction motor and the dynamometer. The rotor terminals are left open. The AC power supply is then turned on. I need to find voltage between any two of the open rotor terminals. Homework EquationsThe Attempt at...
  4. T

    How to calculate stator to rotor winding turns ratio?

    Homework Statement I have a set of data that I need to use to calculate the stator to winding turns ratio. A hint was given: "The rotor current measured is the rotor winding current. However, the rotor current we use for our calculations is the current referred to the stator side of the...
  5. D

    Modal Analysis of a Rotor Blade Using Simpack

    Hi everyone, I am relatively new to Simpack and would appreciate some help with getting started. Basically I am trying to obtain the displacement of a rotor blade as it rotates (I already have the model). I want to have the displacements of each modal shape along the entire blade radius. Now...
  6. 0

    Mechanics in a rotor problem

    The free boy diagram of one person inside the rotor should have three vectors: weight down, friction up, normal to the center of the cylinder. Is friction force given by centripetal force * static friction coefficient? Normal and centripetal are the same vector in this problem. Is minimum...
  7. H

    Showing Rigid Rotor Microstates with Angular Momentum ≤ M

    Homework Statement By evaluating the "volume" of the relevant region of its phase space, show that the number of microstates available to a rigid rotor with angular momentum less or equal to M is (M/ħ)2. Homework Equations Consider the motion in the variables θ and φ, with...
  8. P

    Ansoft Maxwell -- shaping an interior electric motor rotor

    For shaping an interior PMSM rotor from top figure to as in bottom fig, I made an equation based curve, united with another curve , made a surface using coverline and united that shape with my rotor. When validated it showed band and rotor intersecting and I adjusted the band - DiaGap. Then...
  9. M

    Engineering Using the Locked Rotor Test to find parameters of DC motor?

    Homework Statement A locked rotor test is performed on a permanent magnet DC machine with the following results: Terminal Voltage 5 V DC Input Current 10 A DC Locked rotor torque. 20 Nm a) Making suitable approximations deduce the effective rotor resistance in ohms? b) Making suitable...
  10. Salvador

    Outer monopole generator rotor

    Hello, Happy New Year everyone. I wanted to know or can anybody show me how would a rotor like that look like or how it would be wound? I need the rotors outer part that faces the stator to have a single magnetic pole coming out of it , not like typical rotors that have poles on them and one is...
  11. D

    Modeling a quad rotor vibrations

    Homework Statement I have a system of five coupled ODEs. I believe I should be able to reduce it down to four coupled ODEs, but I am not sure how. This system is modeling a quad X rotor where the arms are viewed as end loaded cantilever beams with motors attached. Homework EquationsThe...
  12. W

    Squirrel cage induction motors - rotor issues

    Hello all, I am currently involved in a diagnostic project for an induction motor with suspected rotor stator contact. all critical dimensions have been checked but the question has been raised by none electrical observers: Does the location of the rotor bars effect the magnetic center line...
  13. B

    Replaceable alternator rotor windings

    Has anyone ever heard of a rotor winding that can be interchanged with different shaft lengths? I'm trying to find a way to create a 3-phase alternator with a through shaft to attach pulleys on each end.
  14. H

    Helicopter hovering in crosswind with tail rotor

    Homework Statement A helicopter is hovering in a steady cross wind at a gross weight of 3,000lb. The helicopter has 275 hp delivered to the main rotor shaft. The tail rotor radius is 2.3 ft and has an induced power factor of 1.15. The tail rotor is located 15.3 ft away from the main rotor...
  15. M

    Analyzing Forces in the Rotor Ride at the State Fair

    Homework Statement In the Rotor Ride at the NM State Fair, passengers stand with their backs to the wall in a giant rotating drum with a radius of 10 feet. The drum is brought up to a speed of 33 1/3 RPM, and then the floor is lowered, leaving the passengers suspended above a giant hole in the...
  16. O

    Rotor Disassembly from Vehicle Alternator - How?

    Good evening, Before I start, I'm sorry if this is in the wrong forum, I wasn't sure where to post such a question. I have an car alternator which I'm going to be experimenting with to generate electricity from the wind. It's a GM Valeo model, possibly taken out of a Vauxhall. Right now...
  17. Y

    MATLAB Savonius rotor simulation in matlab/simulink

    hi there, i'm trying a to simulate a savonius rotor in simulink. below is brief summary of how much i have done:- 1. derived the equations for torque. 2. MATLAB code done. 3. in simulink the equation I'm using to get the angular velocity and angular position is T...
  18. K

    Gas Turbine: Making Rotor as Stator and vice versa

    Hi, Just wondered why the rotor of a gas turbine (generally inside) is not made stationary and the casing (drum that surrounds the rotor) made to rotate...kind of reversed gas turbine... One limitation i thought about was the combustion can placement... Any other views as to why we don't see...
  19. S

    What about motor rotor size?

    Specifically, this is all to do with rotor size of brushless DC motors and how it plays a part in calculating angular velocity / volts / amps / torque. There is no single equation to be solved here. Any relating information or equations..., any and all, please jump in. I've been looking at all...
  20. J

    Effect of wind turbine yaw on rotor rotational speed

    Hi From what I understand as the rotor yaws, there are gyroscopic forces that act upon it and the magnitude of these depends on the speed of yawing (e.g. 10 degrees per second). What happens to the rotor rotational speed during yawing? Does it slow down? Is the aim to slow down the rotor...
  21. J

    BLDC rotor and stator poles

    hi, There is one thing that I do not understand and nor do I find any direct explanations for it. Is there any relationship between no of rotor poles and no of stator poles in BLDC motor (or PM Synchronous Motor)? I have read somewhere there doesn't have to be. I can imagine if no of poles are...
  22. P

    Induction motor rotor and stator fluxes

    Hi, When a load is applied to the rotor of an induction motor, the rotor speed decreases and as a result, the induced currents in the rotor and the torque produced increases due to the relative speed difference between the rotor and the rotating field within the stator. My question is...
  23. E

    3 Phase Rotor / Stator Swapping ?

    3 Phase Rotor / Stator Swapping ? I have been toying around with the following idea : (specific application project) Normally a stator is the external housing of a motor and is fixed to a structure - the rotor is the shaft through the middle of this stator etc. and is rotating at ...x... RPM...
  24. N

    Understanding Rotor RMF in Squirrel Cage & Slip Ring Induction Motors

    is the rotor rotating magnetic field(R-RMF) present in squirrel cage induction motor (SCIM). Is it same as in 3 phase ROTOR winding of slip ring induction motor (SRIM), generating rotor RMF. * THE 3 phase, supply given to stator 3 phase winding of SRIM, generates (RMF), which cuts the rotor 3...
  25. F

    E-field Perturbation of 2D rotor. Show Y_10 couples ground state?

    Homework Statement Consider a molecule with an electric dipole moment d. The Hamiltonian of a molecule in the external electric field E is: \hat{H} = \frac{\hat{L^2}}{2I} - dE \cos{\theta}, where the polar angle \theta characterises the orientation of the molecule. (We have chosen the field...
  26. B

    Quantum Rigid Rotor Homework: Energy Eigenstates & Degeneracy

    Homework Statement Consider a rigid rotor with moment of inertia Ix = Iy = I, Iz = (1 + ε)I Classically, his energy is given by, E = L^2/2I. (c) What are the new energy eigenstates and eigenvalues? (d) Sketch the spectrum of energy eigenvalues as a function of ε. For what sign of do the...
  27. T

    What is the speed of the quad rotor with this given detailes?

    so a single-phase quadrotor with the weight of 100 grams has 100 Newton thurst force from motors 2 and 3 and 50 Newton thurst force from motors 1 and 4. given this detailes, at constant movement and ignoring other factors, what will the speed of the quad rotor be? show me your calculations, also...
  28. S

    Induction Motor:No of rotor poles not equal to no of stator poles

    Consider 2 cases case 1: no of rotor poles = 2 no of stator poles =4 case 2: no of rotor poles = 4 no of stator poles =2 What will happen in case 1 & 2 ? Will Induction motor run?
  29. S

    3-phase Induction Motor:Supply given to Rotor & Stator winding shorted

    In a 3 phase slip ring Induction motor, 3 phase balanced supply is given to rotor winding & stator winding is short circuited . Then rotor would - run against the direction of rotating field. Can anyone explain this phenomenon?
  30. B

    Brushless DC Rotor Position Question

    Hi. I am curious about ways to sense the position of a rotor in a BLDC motor. I am familiar with hall sensors and back emf but am wondering if there are other ways to find the position of a rotor maybe more accurately. I had an idea about using a laser and a photoresistor around the...
  31. C

    Intermeshing rotor helicopters/synchropters hard to fly?

    i was reading an article about the Kaman K-max being used as a UAV, and there were comments about how this helicopter is harder to fly than a traditional main-and-tail-rotor helicopter ... the large number of accidents of the K-max also seems to suggest the same thing why is this? to me, the...
  32. A

    DC motor rotor + stator : torque by attraction ?

    DC motor rotor + stator : torque by attraction ? [Solved] So on that image there's a very simple dc motor. Knowing that F = B*I, the force acting on the wire can be represented as on the image. Also the current passing through the rotor will create a magnetic field, represented by Brotor...
  33. A

    Calculating Rotor Moment of Inertia and Time to Slow Down

    Ok, here we go. In a rotating mechanism (helicopter rotor), at a state of equilibrium, the rotor consumes a certain amount of energy from the shaft to maintain a constant angular velocity (since there is a measure of resistance present over the span of the rotor). Lets suppose that the...
  34. M

    How Does Rotor Pole Count Affect AC Motor Performance?

    Hello, Generally and specially in AC motors, what is the effect of the no of poles of the rotor on the motor performance? if it's same or less or more than the no of poles of the stator? Thanks
  35. P

    Rigid Rotor question requiring quantum mechanics.

    Homework Statement A rigid rotor with moment of Inertia I is known to be in a state with eigenfunction Y3,-2(θ,∅). A. What is the rotational energy of the rotor in terms of I and h bar. B. What is the uncertainty in the measurement of the energy of the rotor? Homework Equations...
  36. H

    Finding static pressure of rotor

    I've been reading a helicopter aerodynamics book and found that you can only find the induced velocity by using the Momentum theory and Bernoulli's Principle. If I don't know the thrust the rotor is generating, then I have to find the induced velocity of the rotor, where Atmospheric pressure =...
  37. B

    Induction Motor Rotor Speed: Beyond Synchronous Speed

    What will happen if the rotor speed becomes larger than the synchronous speed for induction motor?
  38. K

    Material Selection & Process Selection for Rotor Steam Turbine

    Hi I need to perform a material selection case on the rotor of a steam turbine. Both material selection as process selection have to be made. Since my background is rather chemical than mechanical or material engineering I've encountered some difficulties. I hope you can help me with them. For...
  39. M

    Helicopter rotor acceleration

    How would you calculate the acceleration of the following two points? http://img341.imageshack.us/img341/917/helicoptor.jpg Uploaded with ImageShack.us1) The tip of the helicopter blade The diameter of the hub = d The length of the rotor = l The flapping angle: theta = A sin(omega*t)...
  40. P

    Which Poles Do I Connect for Short Circuiting in a Wound Rotor Motor?

    Hello, I have problem with an old asynchronous motor with wound rotor it is VEB MEZ VSTEIN.I am intending to run the motor via frequency inverter by connecting it to the stator windings. I need to short circuit the rotor, but there are 6 poles coming out (a,b,c and a0,b0,c0) from the wound...
  41. B

    Consider a rotor rotating inside a stator. The rotating torque

    Consider a rotor rotating inside a stator. The rotating torque produces a moment. This moment will be counter balanced by generating a counter- torque (by rotating the stator or some other element in counter direction). Now, my query is that I have a pump rotating a considerable mass and this...
  42. A

    Induction motor fed from rotor.

    What will happen if an induction motor is fed from rotor side. I mean if i supply say 50HZ frequency supply to rotor through slip rings and have my stator windings connected to variable resistances will the rotor start to rotate and if it does in which direction?
  43. C

    Rotor vs Propeller: Know the Difference

    Hey guys, I have always wanted to know the difference between propeller and rotor though they are used for similar applications. I never researched on it until now when I had to write it down as one of my assignments. Any answers will be appreciated and also if anybody can refer me to any books...
  44. K

    Single Rotor Versus Coaxial Rotor Lift

    I'm having a tiny debate with someone over whether a 2nd coaxial rotor generates additional lift for a helicopter by itself or the helicopter has additional lift only due to the elimination of the tail rotor so 100% power goes to generating lift? My theory is that it does not generate...
  45. T

    Rigid Rotor: Finding Angles

    Homework Statement I am trying to find the angles (theta, phi) it is most probable to find the rigid rotor for the spherical harmonic m=1, l=1 Homework Equations The equation given is Y = (3/8pi)1/2*sin(theta)*ei*phi The Attempt at a Solution I have tried to solve it by...
  46. T

    Understanding the Energy Differences: Rigid Rotors vs. Harmonic Oscillators

    I am currently taking a modern physics course, and we have a take home quiz. I am not savvy in physics at all, much less quantam mechanics, so any and all help is greatly appreciated. My question is: Explain what is the difference in terms of energy between the ground states of rigid rotors...
  47. J

    Axial flux generator dual rotor question

    I am building an axial flux generator with dual rotor and single stator. I was doing calculations and have a magnet pole pair question i need help with, there are 12 magnets on each rotor with North pole on one rotor across from South pole on the other rotor. Since there are 24 total magnets...
  48. H

    Velocity Calculation for helicopter rotor question

    Hello, I'm creating an excel file to calculate the velocity of one rotor of a helicopter, and I'm getting really weird answer, in comparison to the one a friend of my who does aerospace engineering give me. I don't do an aerospace engineering course but this is a project I've been researching...
  49. F

    Asynchronous motors - the heat of the rotor

    So I was reading about asynchronous motors, and it seems the motor works better when the resistance of the rotor is smaller. This is fairly obvious, because the smaller the resistance, the bigger the inductive currents and therefore more mechanical force is applied on the rotor, thus its doing...
  50. M

    Tilting a helicopter rotor, does it create torque?

    Hello I am making a helicopter flight simulation and I need an answer to this question: when you push the cyclic forward, does this create a torque which will rotate the helicopter. if the answer is yes, please tell me what counteracts this torque and stops the rotation when I return the...
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