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. R

    I V * grad(V) = grad(V^2/2) - rotor(omega)

    Hi, while studying for my aerodynamics class, I encountered this equivalence that my professor gave us as a vector identity: $$ \mathbf{V} \cdot \nabla \mathbf{V} = \nabla\left(\frac{V^{2}}{2}\right)-\mathbf{V} \times \boldsymbol{\omega} $$ where ## \boldsymbol{\omega} = \nabla \times \mathbf{V}...
  2. HauTo

    Help to calculate rotation speed of rotor

    Hello everyone, i have a question, how to find wind turbine rotor rotation speed based on freewheel rotation speed of rotor (RPM)(torque = 0)? Thanks for your attention.
  3. Astronuc

    NASA NASA - Bimodal NTP/NEP with a Wave Rotor Topping Cycle

    New Class of Bimodal NTP/NEP with a Wave Rotor Topping Cycle Enabling Fast Transit to Mars https://www.nasa.gov/directorates/spacetech/niac/2023/New_Class_of_Bimodal/ Ryan Gosse, University of Florida, Gainesville, FL...
  4. A

    Induction motor rotor design features

    I had to repair (change bearings) on a single phase induction motor recently and I recalled an age old question I've had. What are the rotor end ring blades made for ? The only reasonable answer I can come up with is - they are for cooling of the stator winding ends that extend out of the...
  5. patric44

    Nuclear rotor model wave function

    hi guys I am recently taking a Nuclear structure course, and have a lot of questions regarding the nuclear rotor model. in most nuclear physics books the I have, the wave function associated with the rotor model of the nucleus is written in terms of the Wigner D functions , like the expression...
  6. T

    Engineering Spectrum analysis of unbalanced rotating rotor

    Spectrum of acceleration vs frequency Results of balanced condition Results of unbalanced condition
  7. H

    Why do we need stators in compressors or turbines?

    Hey Everybody! I was wondering why do we need Stators in compressors and turbine, for instance the goal of compressor is to increase the outlet pressure, so that the combustion is effective, but why we don't put just Rotors and no stators in the compressor (or Turbine).
  8. M

    Single main rotor helicopter

    Hello everyone! I am currently developing a thesi to become an aeronautical engineer. I am trying to reproduce the NASA report "a mathematical model of a single main rotor helicopter for piloted simulation". I already built a simulink model but i am having a bit of trouble looking at the...
  9. adamaero

    Engineering How to calculate rotor flux of the three phase squirrel cage induction motor?

    Three phase squirrel cage induction motor with given parameters (stator winding connected in delta) nominal power: Pn=22.4kW nominal stator voltage: Vsn=230V nominal stator current: Isn=39.5A nominal stator frequency: fsn=60Hz nominal speed: nn=1168min−1 number of pole pairs: 3 stator...
  10. J

    Response of a motor rotor to just 1/60th of a second of current

    Where can I get actual demonstration that a 1/60 sec current can move the magnet. That is. You just apply 1/60 sec current without other power in the middle of it, will the magnet move that fast in 1/60 sec? Or does motor runs because of inertia of the previous rotation?
  11. T

    Automotive Cancelling effects on a larger brake rotor

    Hello all, I am struggling to find out what exactly makes to have very little advantage in terms of cold stopping distance when you fit larger brakes on a car. Important note, the discussion is only regarding the braking power in the very first stop, before the heat starts to become a problem...
  12. vish1711

    Synchronous Generator PMG Rotor Damaged

    Generator - 1800rpm, 11kV, 656A. While running Gen, a large load was turned on, and excitation voltage went from 23V to 120V, but that's a normal situation that happens every time and on all Generators. But this time after turning on the large load, vibrations started increasing, and Gen tripped...
  13. B

    B Question about a Rotor Ride in a amusement park

    Hi I don't understand why the static friction force is maximum in this situation?
  14. O

    Transorbs in a generator rotor

    is there some special reason why transorbs would be inserted into the rotor circuit of a capacitor controlled generator, rather than diodes? And since I have no way of determining the value of the existing transorbs, could I simply substitute diodes. Diodes are the "normally" expected component...
  15. kolleamm

    Why do the phases of a motor spin the rotor?

    Assuming we have a 3 phase motor I've always wondered why is it that the rotor spins rather than just being compleltly pulled towards the direction of the phase or the electromagnet? What causes that angular movement?
  16. J

    Engineering Relationship between total Rotor Power and Losses

    Equations: Pr : Pm : Pc = 1 : 1-S : S Total Power into rotor: Pr=I'22R'2/S Mechanical Power Output: Pm=I'22R'2(1-S)/S Power loss in rotor: Pc=I'22R'2So I'm a little skeptical of my answer here. Seems a little too easy, which normally means I've missed to mark by about 100 miles. Attempt...
  17. F

    What causes an AC motor to pull locked rotor amps?

    When an alternating current motor first turns on, what causes an alternating current motor to pull locked rotor amps for approximately one second after first turning on as opposed to just pulling the same amount of amps the entire time? What causes the amperage on an AC motor to drop after...
  18. N

    Lenz's Law for a rotating PM motor rotor spinning in a thin CU tube

    The motor is required to operate at its resonance frequency and I am looking to add a thin-walled (0.010") copper tube inside the stator bore to add some damping. The current motor air-gap is 0.015". If I install a copper tube in the stator bore bonded to the stator and leave a 0.005" air-gap...
  19. F

    What causes locked rotor amps on a motor?

    When an electric motor first starts running, the motor will draw approximately 5X the normal amp draw of the motor for approximately the first half second that the motor runs. The amps that an electric motor draws for about half a second that are about 5X the normal amp draw of the motor are...
  20. MichPod

    Susskind's treatment of a rotor in a magnetic field

    My question is related to the chapter 10 of L.Sussknd's book on analytical mechanics named "The theoretical minimum". There he considers dynamics of a charged rotor in magnetic field using Hamiltonian formalism and poisson brackets. He also introduces a treatment of the same kind for a...
  21. J

    Air resistance: cylindrical rotor in stator with air gap

    Hello, I am currently doing research on the aerodynamic properties of a rotating cylinder in a cylindrical housing. The cylinder represents a rotor in a electric motor. The air gap between rotor and stator is about 0.5mm. I'm looking for a theoretical analysis and calculation on the...
  22. niaz

    Cylindrical rotor generator power under loss of excitation

    Hello all, I want to know about turbo alternator real power producing capability under loss of excitation condition. Normally in salient pole rotor have capability to supply real power under field current=0 condition, as there is reluctance power developed. But what about non salient pole...
  23. W

    Motor: stator and rotor magnetic strength

    What is the perfect ratio of rotor pm magnetic strength:stator em magnetic strength ? What will happen if we have N52 rotor magnet surrounded by stator 187amp/turn electromagnet ? Will stator magnetic field will be sufficient for revolution of rotor??
  24. Cocoleia

    3-phase delta supply to a 3-phase synchronous motor?

    Homework Statement Can we use a 3 phase delta supply to a 3 phase synchronous motor who's stator windings are connected in star (wye)? The Attempt at a Solution I was thinking no, since I read in my notes that the rotor has to be supplied with a "continuous current" But I'm not sure. I have...
  25. T

    Increasing the number of pole shoes on an alternator rotor

    Would like to know how to determine if 2 additional pair of rotor pole shoes can be added (re-designed) to rotor for existing 72 slot alternator stator. Present claw pole rotor has a total of 12 and I would like to have a total of 16. Any assistance would be appreciated. Thank you.alternator...
  26. F

    Induction motor - calculating rotor flux angle

    Hello. I'm trying to write my own soft for Field Oriented Control of induction motor. I have finished hardware - 3ph 3kW inverter, controlled by STM32F4, and V/F open loop algorithm to control ACIM - it works. Now I'm trying to implement FOC algorithm. As we know we need to do Clark&Park...
  27. Noaha

    Rotor and stator flux in 3 phase Induction motor

    The rotor and stator flux speed are stationary with respect to each other in 3 phase induction motor. What will happen if there is relative speed between them? How these two fluxes interact with each other to develop a torque?
  28. P

    Rotor magnetic field and stator magnetic field

    This is one of the big confusions i have. When rotor magnetic field is 90 degrees with respect to stator magnetic field we get maximum torque. In field oriented control the a, b, c axis is converted to d and q axis. So making d axis to 0 and q axis to torque and running through pi loop does...
  29. P

    Clarification of the motor rotor position

    I was referring to the following statement in the document which confused me and also attaching the document for your reference. "First, we need to know the rotor position. The position is typically related to phase A." How the above statement is true. Please help me to understand. I am...
  30. D

    [Mechanics] Friction decelerating a helicopter rotor assembly

    Homework Statement A Chinook helicopter’s rotor blades and hub have a top speed of 300 revs/min and a combined mass of 300 kg. On a maintenance test the blade assembly is allowed to stop without applying the brake, in this condition the blades take 48 seconds to come to a standstill. The...
  31. B

    How to measure the moment of inertia of a motor's rotor?

    Hello, I need to measure the moment of inertia of a DC motor's rotor. Any suggestion? Thanks
  32. Stef

    Rotor Analysis -- Big deformation problem

    Hi everyone, i am currently doing a rotor analysis with "modal analysis" on Ansys and even though my rotor's specs are L=145mm D=10mm and the rotating velocity is 10000rpm i get a deformation of 100mm at most of the modes. I have read that this might be cause of a mass-normalized value but i am...
  33. PhysicsCollegeGirl

    Amusement Rotor Ride Explanation

    1. Homework Statement An amusement park ride consists of a large vertical cylinder that spins about its axis fast enough that any person inside is held up against the wall when the floor drops away (see figure). The coefficient of static friction between person and wall is μs, and the radius of...
  34. S

    Fatigue of a Rotor: Predicting Life Expectancy with Variable Cyclic Stresses

    I have a fast rotating rotor spinning over 2 axis (over its main axis and over an external axis - the two axis are perpendicular to each other). Easiest to imagine this is like a windturbine yawing as it follows the wind direction.Each of the two rotations obviously causes a distinct centripetal...
  35. Mr lee

    Magnus effect in flettner rotor

    Mr lee said: ↑ hi -new but enjoyed years, wit and wisdom Flettner rotor on a boat - ie. magnus effect Can the vertical rotor create lift? a curve balls 'laces' exaggerate and bend the magnus effect. can you replicate this effect on a rotor? --perhaps to enable another direction of force-- up...
  36. F

    Need help with BLDC motor rotor design

    Trying to design a motor for a learning project. Finished the math but having a lot of trouble with design questions. Can anyone give me some insight. For the rotor in this picture there is a ring magnet. Is the magnet glued on? I think it is glued onto electrical steel. 2nd question, on the...
  37. W

    Wankel/rotary engine efficiency

    I was just wondering how we can find out the efficiency of a rotary engine? Obvious, it is more efficient than a gasoline/diesel engine.For example the RX8 on 1.3 L in 2 rotors get 250 hp which is quite impressive for that capacity,also it works in 4 stroke,and the power to weight ratio is...
  38. cnh1995

    Rotor and negative sequence impedance of alternator

    When an alternator is supplied with a 3-phase voltage and its rotor is rotated in opposite direction to that of the stator rmf, the ratio phase voltage/phase current is the negative sequence impedance of the alternator. My understanding of this is as follows: When rotor is rotated in opposite...
  39. D

    Kinematics of rigid rotor - angular acceleration

    Homework Statement http://pho.to/A7jM2 Homework EquationsThe Attempt at a Solution My question is why the answer of question 15.258 (a) about the angular acceleration of rod BD isn't correct. I used the realtion of tan(25) in the end of the solution.
  40. T

    Induction motor locked rotor test

    For the locked rotor test I have these values, P1 = 620W Stator line voltage = 32V Stator line current = 8.4A To calculate active power/phase, Po = (P1+P2)/3 But I don't have P2, Is P1 maybe equal to P2 ?
  41. D

    A question about kinematics of a rigid rotor

    Homework Statement Hey guys, I have a question about this(I know you want to see my soultion, but I've done it ok except the 2 things I'm asking about) : http://athena.ecs.csus.edu/~grandajj/me143/1_Introduction_Tires_WM2D/1_4_2_Exercise_2.pdf 2 questions: 1. How can I undersdant that I...
  42. Salvador

    Please confirm magnetic levitating rotor

    what do you think is this video real or is there a trick somekind ?
  43. Usamah Abdul Latif

    Coaxial Rotor UAV Helicopter Hover Performance

    Hi Guys! I'm doing a conceptual performance calculation and analysis on co-axial rotor UAV helicopter on hover. However, I'm having conflicting results and if anyone can help me, it would be very great. The design constant of the helicopter are as follows: MTOW = 20 kg κ = 1.15 (Induced Power...
  44. C

    Rotor blade thrust - torque and angular velocity

    Imagine a motor, spinning a rotor blade around and around and around and around and around... How does the angular velocity of the rotor blade, and the torque affect the thrust produced?
  45. ATY

    Chord length and radius of a wind turbine rotor blade

    Hello, I have a question about the chord length of rotor blades from wind turbines. I do not really understand what the difference is to the radius of a wind turbine. I can not find a real explanation, but it seems to be very important. I know that the formula of the chord length depends on...
  46. cnh1995

    Rotor EMF in squirrel cage induction motor

    In a 3 phase induction motor,when stator rmf rotates, it cuts the rotor bars and induces an emf in them. Is this emf sinusoidal? I mean shouldn't it be a square wave since the rotor "bars" are being cut by the flux, like in case of concentrated stator windings of a synchronous generator? If the...
  47. LesterTU

    Calculating Apparent Weight on a Rotor Ride

    Homework Statement A 30-kg child is on a rotor ride at a carnival. The radius of the rotor is 3 m and it completes 0.4 revolutions in one second. The coefficient of static friction is 0.6. What is the magnitude of the child's apparent weight? Homework Equations ΣFx : FN = mv2/r ΣFy : Ff = Fg...
  48. Salvador

    Need help understanding strange idea (electric motor rotor and stator)

    A dc brushed motor with a commutator, the stator isn't fixed to anything and is left freely on a desk for example, now apllying power the rotor starts to turn, if I take the rotor and hold it with hand the stator now starts to turn around , I assume this happens because the stator poles and...
  49. R

    Big rotor vs multiple small rotors in a Permanent Magnet Generator

    Hello guys, I am trying to build a permanent magnet generator, I have 48 magnets and 18 coils, and I am hesitating betwen 2 configurations. Configuration A: 2 huge steel plates with 24 magnets on each and an 18 coil stator between them or Configuration B: 4 smaller plates stacked to sandwich 3...
  50. D

    Centrifugal Force: Balancing a swing bucket rotor

    A lab mate and I got into a discussion on how to properly balance a swing bucket rotor. This is different than a normal centrifuge in that there are buckets that swing out once spinning begins. In a standard centrifuge balancing is simple - it's just the same weight directly opposite your...