the synchronous machine preliminaries
Tài liệu The Ego Machine ppt
... of the manuscript still in the typewriter The other spouse would routinely continue the story where the first had left off They alternated in this manner as many times as necessary until the ... distracted him He studied the instrument briefly, then clapped his hands sharply together an inch from the mouthpiece There was a sharp, anguished cry from the other end of the line "Very good," ... worse Operating on the theory that the old Nicholas Martin had come into it, the theater, which had breathed an expensive air of luxurious confidence, chilled toward him The nap of the Persian rug...
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Tài liệu The Time Machine pptx
... said the Editor of a well-known daily paper; and thereupon the Doctor rang the bell The Psychologist was the only person besides the Doctor and myself who had attended the previous dinner The other ... them when I saw their little pink hands feeling at the Time Machine Happily then, when it was not too late, I thought of a danger I had hitherto forgotten, and reaching over the bars of the machine ... Filby’s eye over the shoulder of the Medical Man, and he winked at me solemnly 14 The Time Machine II I think that at that time none of us quite believed in the Time Machine The fact is, the Time Traveller...
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The Dueling Machine pot
... cocked an eye at the chief meditech, hovering at the edge of the little group The meditech, one of the staff that ran the dueling machine, pointed out, "The Prime Minister has passed the examinations ... taken the electroencephalographic records of clinical cases of catatonia and run them through the machine' s input unit The machine immediately rejected them, refused to process them through the ... the dueling machine chamber Neither of them slept well that night The next morning, after an unenthusiastic breakfast, they found themselves standing in the antiseptic-white chamber, before the...
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The Anime Machine: A Media Theory of Animation
... that the machine theory” of animation moves beyond all that In effect, the machine theory charts a course between these two ways of looking at Japanese animations What then is machine theory? ... over the image The pan over an image, however, can be as easily produced by sliding the drawing under the camera, rather than moving the camera Because of the relative immobility of the camera, the ... to the same space as the perceived objects: the traveler saw the objects, landscapes, etc through the apparatus which moved him through the world.”4 On the other hand, Schivelbusch notes, “the...
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The Influencing Machine: An Introduction potx
... the Republic survives The irony is that the more people participate in the media, the more they hate the media The greater the participation, the greater the paranoia that the media are in control ... the convulsions roiling the media augur the apocalypse We’ve been here before: the incivility, the inanities, the obsessions, and the broken business models In fact, it’s been far worse and the ... to their public because, if they lose that allegiance, they lose money Sometimes the press leads the public; sometimes the public leads the press The media, at least the mainstream media, don’t...
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The time machine
... The Morlocks, on the other hand, represent the dehumanisation of the working classes Unlike the Eloi, they still know how to make things, but they have become brutal predators of the night In Wells’s ... groups Ask them to imagine that they are going to travel 1,000 years into the future Ask them to discuss these questions (a) Are they going to enjoy the experience? Why/why not? (b) What will they ... students to know the new words found on page 78 of the Reader They are practised in the ‘Before you read’ sections in the back of the book (The definitions are based on those in the Longman Active...
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the induction machine handbook chuong (1)
... discovered the electromagnetic induction law around 1831 and Maxwell formulated the laws of electricity (or Maxwell’s equations) around 1860 The knowledge was ripe for the invention of the induction machine ... currents in the short-circuited (or closed) windings of the rotor The interaction between the stator produced field and the rotor induced currents produces torque and thus operates the induction ... applications, the induction motor seems now ready to make the electric starter/generator system aboard the hybrid vehicles of the near future The new challenges in modeling, and optimization design in the...
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the induction machine handbook chuong (2)
... cases the internal primary is the mover and the external secondary is at a standstill In most rotary IMs, the primary is the stator and the secondary is the rotor Not so for linear induction machines ... fact, it is 25 to 60% of the rated current depending on the machine airgap g to pole pitch τ ratio The higher the ratio τ/g, the smaller the magnetization current in p.u The stator and rotor currents ... (Figure 2.9) The slip rings are visible to the right The stator-placed brush system is not Single-phase-supply IMs have, on the other hand, in general, two windings on the stator The main winding...
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the induction machine handbook chuong (3)
... to this combination The insulation of the coil conductors (turns) is applied before inserting the coils in slots The coils are vacuum also impregnated outside the machine The slot insulation ... All these insulation accelerated life tests involve the ageing of insulation test specimens until they fail at temperatures higher than the operating temperature of the respective motor The logarithms ... motor The logarithms of the accelerated ageing times are then graphed against their reciprocal Kelvin test temperatures (Arhenius graph) The graph is then extrapolated to the planed (reduced) temperature...
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the induction machine handbook chuong (4)
... ……… For the fundamental, ν = 1, we obtain the maximum amplitude The higher the order of the harmonic, the lower its amplitude in (4.8) While in principle such a primitive machine works, the harmonics ... layer and the other side in the second layer They are connected observing the inward (A, B, C) and outward (A’, B’, C’) directions of currents in their sides Connecting the coils per phase The Ns/2m ... Having two current paths, the current in the coils is half the current at the terminals Consequently, the wire gauge of conductors in the coils is smaller and thus the coils are more flexible...
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the induction machine handbook chuong (5)
... replaced by the actual (designed) maximum flattened flux density Bgm, at an angle θ = 30°/p1, which makes the length of the flux lines in the back core 2/3 of their maximum length Then finally the calculated ... have consequences in the phase current waveforms for the two connections Finally, the saturation produced third and other harmonics influence, notably the core loss in the machine This aspect ... let us calculate the value of F1m To solve the problem in a rather simple way, we still assume a sinusoidal flux distribution in the back cores, based on the fundamental of the airgap flux density...
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the induction machine handbook chuong (6)
... respectively As the pole pitch of the harmonics is τ/ν, their fields not reach the back cores and thus their saturation factor Ksν is smaller then Ks The higher ν, the closer Ksν is to unity In a ... fields The airgap flux does not reach the other slotted structure (Figure 6.10a) while the zig-zag flux “snakes” out through the teeth around slot openings In general, they may be treated together ... rotor phases In reality the flux in the rotor varies at Sf1 frequency, while in the stator at f1 frequency The amplitude is the same and, with respect to each other, they are at stall Now we...
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the induction machine handbook chuong (7)
... S.A.Nasar………… ……… The lower the power factor at ideal no-load, the lower the core loss in the machine (the winding losses are low in this case) In general, when the machine is driven under load, the value ... the value of Pelm is zero, so the machine driven at that speed absorbs power in the stator to cover the winding and core loss Motor no-load mode is when there is no-load torque at the shaft The ... means that either n < and n1(f1) > or n > and n1(f1) < In both cases, as S > (S > 0), the electromagnetic power Pelm > and thus flows from the power source into the machine On the other hand, with...
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the induction machine handbook chuong (8)
... constant under steady state and the machine behaves like a synchronous machine with the torque dependent on the power angle δ (S = f2/f1 = ct) On the other hand, the frequency f2 may be varied ... converter The machine speed n is n= f1 ± f p1 + p (8.71) The smaller f2, the smaller the rating of the corresponding frequency converter The behavior is typical to that of a synchronous machine ... when the load torque decreases, to reduce the flux level in the machine and thus reduce the core losses and increase the power factor and efficiency while stator current also decreases The slip...
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the induction machine handbook chuong (9)
... IN THE END RINGS VIA THE MULTILAYER APPROACH As the end rings are placed in air, although rather close to the motor laminated stack, the skin effect in them is routinely neglected However, there ... On the other hand, if slot leakage saturation occurs only on the teeth top and the teeth, additional saturation due to skewing does not influence the flux lines distribution within the slot, the ... calculate the final values of leakage inductances Now if the skewing flux occurs both in the stator and in the rotor, when the leakage inductance is calculated, the rotor one will include the skewing...
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the induction machine handbook chuong (10)
... only as the harmonics wavelength is smaller than that of the fundamental and therefore the flux paths close within the airgap and the stator and rotor teeth/slot zone The slip Sν ≈ and thus the slip ... order is a multiple of the number of slots (10.12) The stator (rotor) mmfs may produce harmonics of the same order either as sourced in the mmf or from the interaction with the first airgap magnetic ... components close their flux lines axially through the stator frame then radially through the end frame, bearings, and axially through the shaft (Figure 10.3) The factor ch accounts for the magnetic...
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the induction machine handbook chuong (11)
... when the IM is static converter fed, and thus the voltage time harmonics content depends on the type of the converter and the pulse width modulation used with it The space harmonics in the stator ... associated with them, but the higher frequency flux harmonics may lead to larger core loss On the other hand, the commutation losses in the PWM converter increase with carrier frequency The optimum ... means that the skin effect is not significant Therefore we may neglect the rotor lamination-induced current reaction to the stator field That is, the airgap field harmonics (11.6) penetrate the rotor...
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the induction machine handbook chuong (12)
... (induction) machines, the thermal energy flows from the windings in slots to laminated core teeth through the conductor insulation and slot line insulation On the other hand, part of the thermal ... thermal resistance from the iron core to the air in the ventilation channels Rt5 – thermal resistance from core to air in ventilation channel Rt6 – thermal resistance towards the air inside the ... we may break the motor axially into a few segments and “thermally” connect these segments together To account for thermal transients, the thermal equivalent circuit should contain thermal resistances...
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the induction machine handbook chuong (13)
... t load dt x' The concept of E’ is derived from the similar synchronous motor concept The angle δ is the rotor flux vector angle with respect to the synchronous reference system The steady-state ... Chapter 6, the leakage flux circumferential flux lines at high currents influence the main (radial) flux and contribute to the resultant flux in the machine core The saturation in the stator ... IMs), the cdr – cqr windings account for the skin effect via the double-cage equivalence principle Let us consider also that the core loss windings are coupled to the other windings only by the...
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the induction machine handbook chuong (14)
... satisfy the specifications for the entire speed range as the load torque is below the available motor torque Again the torque in Nm is the same for both motors and the choice between the two ... torque/speed envelope deliverable by the induction motor The first one is the mechanical characteristic of the induction machine itself and the second is the temperature rise For a general purpose ... that the induction motor capability to meet them depends on the motor torque/speed envelope and on the temperature rise for the rated load duty-cycle There are two main limitations concerning the...
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