Transmission Definition and 753 Threads

A transmission is a machine in a power transmission system, which provides controlled application of power. Often the term 5-speed transmission refers simply to the gearbox, that uses gears and gear trains to provide speed and torque conversions from a rotating power source to another device.The term transmission properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differential, and final drive shafts. In America the term is sometimes used in casual speech to refer more specifically to the gearbox alone, and detailed usage differs.
The most common use is in motor vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels. Such engines need to operate at a relatively high rotational speed, which is inappropriate for starting, stopping, and slower travel. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process. Transmissions are also used on pedal bicycles, fixed machines, and where different rotational speeds and torques are adapted.
Often, a transmission has multiple gear ratios (or simply "gears") with the ability to switch between them as the speed varies. This switching may be done manually (by the operator) or automatically (by a control unit). Directional (forward and reverse) control may also be provided. Single-ratio transmissions also exist, which simply change the speed and torque (and sometimes direction) of motor output.
In motor vehicles, the transmission generally is connected to the engine crankshaft via a flywheel or clutch or fluid coupling, partly because internal combustion engines cannot run below a particular speed. The output of the transmission is transmitted via the driveshaft to one or more differentials, which drive the wheels. While a differential may also provide gear reduction, its primary purpose is to permit the wheels at either end of an axle to rotate at different speeds (essential to avoid wheel slippage on turns) as it changes the direction of rotation.
Conventional gear/belt transmissions are not the only mechanism for speed/torque adaptation. Alternative mechanisms include torque converters and power transformation (e.g. diesel-electric transmission and hydraulic drive system). Hybrid configurations also exist. Automatic transmissions use a valve body to shift gears using fluid pressures in response to engine RPM, speed, and throttle input.

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  1. ?

    Reflection and transmission of waves in a medium of nonuniform density

    Hello all, Apologies in advance for the text-wall; this is a rather involved question. I am trying to compute the effective transmission coefficient for a medium of non-uniform refractive index. For simplicity I am assuming the slab has thickness ##d##, that ##n(0)=1##, and that ##n(d)=n##...
  2. Wrichik Basu

    Handling brake failure/stuck accelerator in auto transmission cars

    It's been a year since I was issued my driving licence. I have never driven automatic transmission cars, so my idea about them is very faint. I know that there is no clutch pedal, and one doesn't have to shift gears while driving forward - that's it. Last day, I was watching a TV show where...
  3. K

    Can Superconducting Cables Overcome AC Transmission Distance Limits?

    For underground AC transmission, the line charging current prevents the lines from exceeding 100 km due to the close proximity and high capacitance between the line and ground. If the line was made with superconducting material, I think the same distance limitation applies (assuming same power...
  4. wolfy

    B Quantum Tunneling different individual transmission probabilities

    I have gone through all the videos on Youtube about Quantum Tunneling and became interested in it, so any helpful feedback would be appreciated. Do all the different individual transmission probabilities of electrons, protons, and such remain constant? May I ask what is the "formula" or...
  5. WonderfulWorld

    Long Distance Wireless Power Transmission

    Hi Everyone, I wanted to get the communities take on this. Long distance wireless power transmission. I know that you cannot accomplish this with magnetic fields or with radio waves because the energy falls of with the square of the distance but I have been reading about some unique methods to...
  6. F

    EMF below Power Transmission Lines

    Many years ago I was responsible for maintaining the integrity of a buried fiber optic cable that utilized a railroad right-of-way. Kinda like watching submarine races ! Along much of this routing, transmission towers / power lines would be adjacent to the railroad. Talking with railroad...
  7. DariusP

    I Transmission and absorbance of materials in the deep UV

    I wanted to ask - why do some materials with very high transmittance inevitably start to absorb in deep UV? Is there an explanation?
  8. A

    I Transmission electron microscope beam focusing

    So I'm reading up on this device and what I get is that in all electron guns once the electrons are emitted they would tend to repel one another so in order to make the beam focused instead of spread out across, one uses magnetic fields in the electron microscope, So after the focused beam hits...
  9. Amartansh

    I Intuition behind fields in Transmission lines

    How can traveling wave exist on transmission line if wires are perfect conductors (how voltages can be different at different positions on one perfect conductor)? I mean electric fiels should be zero on equipotential source. I know if length is too long compared to wavelength, we get phase...
  10. E

    Night sky cooling, cooling by transmission or as 'heat sink'

    Howdy all. Regarding the phenomenon of radiative night sky cooling, where an object (such as a blackbody) on the surface of the planet cools via radiating energy into space: can the cooling be ascribed to the transmittance of the radiation through the atmosphere (as such a clearer night with...
  11. entropy1

    I Entanglement setup that shouldn't allow for the transmission of info

    Suppose we produce a polarisation-entangled photon pair ##A_1## and ##A_2##. Then we entangle another pair ##B_1## and ##B_2##. Now suppose that these photons will not interact with anything, sending ##A_1## and ##B_1## to Alice and ##A_2## and ##B_2## to Bob. Alice measures the polarisations...
  12. J

    Engineering 50 Hz High-Voltage Transmission Line

    VS=VR(A1+jA2)+IR(B1+jB2) IS=VR(C1+jC2)+IR(D1+jD2) Given the parameter values in TABLE C and an open-circuit received voltage measured as 88.9 kV, calculate the values of VS and IS and hence the power (PSO) absorbed from the supply by the transmission line on open circuit. VR= 88.9×103 Table...
  13. E

    Transmission line resonator

    Hello everyone, I am studying transmission line resonators and in particular I was considering a particular case of resonator where I have an open circuited quarter wavelength transformer of high impedance terminating a regular 50 ##\Omega## line. If I look at the input impedance from the open...
  14. B

    WKB method transmission coefficient

    Homework Statement: The Task is to calculate the Transmission coefficient with the WKB Approximation of following potential: V(x) = V_0(1-(x/a)²) |x|<a ; V(x) = 0 otherwise Homework Equations: ln|T|² = -2 ∫ p(x) dx I have inserted the potential in the equation for p(x) and recieved p(x) =...
  15. L

    Ground clearances for transmission lines

    Why are ground clearances so large for 765 kV towers? I did a little research on this and even if the switching surge factor is 3 and you have a factor of safety of 1.5, in air (3 kV/mm), it corresponds to 1.62 m of maximum arc length, which doesn't explain why towers are so large. According...
  16. T

    What does it mean to have an complex transmission angle?

    I am getting a complex number for my transmission angle in part (c) but I do not know what that means. Am I even doing this correctly? Any help will be greatly appreciated. Thanks!
  17. F

    Motion transmission through a mechatronical wrist

    Hello, As a personal project,I am currently designing a mechatronic hand, with a number of DOF similar to our hand. I've choose to transmit the axial movement of a finger through a rotary motion, because cable where causing too many backslash an other linear transmission became severely more...
  18. Z

    Comp Sci Rate of transmission in a wireless LAN

    Hi, It says that: When A transmits, it can only be heard/received by B when D transmits, only C can hear/receive from D. Ans : 2 messages/slot Please provide some reasoning for this answer. Zulfi.
  19. Z

    YSICS: Troubleshooting an Equation Plot Issue

    First image showing script and plot Second image where all I have done is slightly change the thickness and now the plot looks very weird. Final image showing the kind of plot I am expecting. Am I just doing something stupid as I can't see what is wrong/different between my equations and the...
  20. amjad-sh

    A Matrix transmission coefficient

    The Hamiltonian of the system I'm working on is in the form : ##\hat H=\dfrac{p^2}{2m}-\dfrac{\partial_z^2}{2m}+V(z)+\gamma V'(z)(\hat z \times \vec{\mathbf p})\cdot \vec{\sigma}## There is translational symmetry in the x-y plane. ##\vec{\mathbf{p}}## is the two dimensional momentum in the x,y...
  21. J

    D Latch using Transmission Gates

    My book has this diagram: Book: Digital Integrated Circuits by Jan M. Rabaey I don't understand the purpose of using the three Inverters. It's not mentioned in the book, nor could I find anything on the internet.
  22. B

    Electricity in transmission lines (Simple V^2/R =P)

    I understand how to get the answer but i don't understand how the answer 0.2 ohms is equal to the resistance of the transmission lines If V^2/P = R then (132kV)^2/800MW = the resistance of the transmission lines, why is the 1% tansmitted as heat relevant at all as this is just one form of...
  23. John FD

    Transmission Line , OPGW Stringing

    Hi, any of you guys have experience paying out conductors leaving the OPGW later on? any idea or procedures needed so that during OPGW paying out stage later on it will not be damaged by the existing conductors. Mentor Note -- Adding link to information about OPGW...
  24. A

    AC Electricity Generation and Transmission over a Single Wire?

    I'm a bit confused as to why can't you transmit AC current over a single wire. For instance, say you have an AC generator which induces potential difference at different points of the wire and thus, creating current. Downstream, the wire can be split and applied to a load. When the wire is...
  25. M

    Impedance graph of a transmission line powersystem in MATLAB/simulink

    I'm trying to plot impedance locus of transmission line in Matlab/Simulink. I have readed some document and thay have plot result like that : I'm trying to calculate impedance when system have short - circuit fault, and plot it on R-X diagram, but i can't get their *red - dot* result like those...
  26. R

    Automotive How Can I Calculate the Minimum Value of n2 in Tractor Power Transmission?

    Hi, I have a problem to design traktor power transmission.Can anybody tell me How to calculate minimum speed for output shaft.I need to calculate number of rotation(maximum and minimum) of the driven shaft Here is the equation: n(driven) max=(n(drive) + n2 (max). (z3/z1)) /(z3/z2 +1) so I get...
  27. Jason-Li

    How to Calculate Transmission Line Coefficients?

    Homework Statement Figure shows a 50 Hz, high-voltage, transmission line. The relationships between the sending and receiving end voltages and currents are given by the complex ABCD equations: where 'S' stands for sending-end and 'R' stands for receiving-end (a) Given the parameter values...
  28. jedishrfu

    More Worrisome News of Prion Transmission

    In a recent Scientific American blog article, it was revealed that prions can be transmitted via optical testing equipment and via sterilized surgical equipment: https://blogs.scientificamerican.com/artful-amoeba/the-case-for-transmissible-alzheimers-grows/
  29. Jason-Li

    Transmission Line Coefficients & Definitions

    Homework Statement (a) State what is meant by a ‘distortionless’ and a ‘lossless’ transmission line.(b) A transmission line has the primary coefficients as given below. Determine the line’s secondary coefficients Zo, α and β at a frequency of 1 GHz. R = 2 Ω/m L = 8 nH/m G=0.5 mS/m C=0.23...
  30. Rx7man

    Microhydro project, transmission line loss

    Well, I've been trying to design a microhydro power project, and I contacted a supplier on Alibaba and we're a bit at odds about the recommended transmission voltage, I'd like to go with 480V and a transformer back down to 120/240V on the other end, their 'engineers' say this isn't necessary and...
  31. Cocoleia

    Power loss in a transmission line

    Homework Statement Homework EquationsThe Attempt at a Solution I have posted the whole solution so it is more complete, but I really only need help with part c (I think) My output power is higher than my input power, I'm not sure where I'm going wrong
  32. Beth N

    Thin-film interference: transmission & reflection of colors

    Homework Statement This is a 2 part question. I have a follow up question from the problem 1. A sheet of glass having an index of refraction of 1.40 is to be coated with a 187-nm thick film of material having a refractive index of 1.55 such that yellow light with a wavelength of 580nm (in...
  33. S

    Electric current flowing in a power transmission line

    A cable of resistance 12 Ohm carries electric power from a generator producing 250 kilowatt at 10,000 volts. Calculate the current in the cable. Solution using P=VI I=25A but using P=I^2R 250000=I^2×12 I =500/root 12 Amps What is the reason for the different...
  34. B

    Optics Experiment involving transmission through a gel and a sphere

    Assume you have the following scenario: Light begins traveling through a gel of index of refraction n=1.34 in a straight line along the x axis. It is then incident on a solid sphere(n=1.36) of radius R in 3-space. Upon transmittance, the light again travels through the gel(n=1.36) and finally...
  35. S

    Transmission electron microscopy -- signal type and importance

    What are the different signals we obtain from TEM and How can we distinguish between them? what are the significances of those signals?
  36. ccdani

    Transmission of blue light through ceramics and surface roughness effects

    Hey :) I measured the transmission of blue visible light (350-550nm) through lithiumdisilicate ceramics with an ulbricht ball and an spectrometer. The light source was a led dental curing unit (bluephase style). The light guide was positioned direct on the ceramics. Now I wanted to test...
  37. G

    Transmission line: leakage current differential equation

    Homework Statement I have a coaxial cable with internal conductor of radius r1 and external conductor of radii r2 and r3. The material of the conductors has a conductivity ##\sigma_1##. Between the conductors there is a imperfect dielectric of conductivity ##\sigma_2##. Consider the...
  38. Marcin H

    Transmission Line Transposition - Conceptual Question

    This is more of a conceptual question and not a homework question. I am having a hard time understanding why we have to transpose transmission lines and how physically moving them changes anything. Do we only transpose in 3 phase transmission lines when we have 3 wires? Does the orientation...
  39. bachir1994

    Electrical energy transmission is on the inside or outside of a conductor

    Hi, Is it true that the transmission of energy is not inside an electrical conductor, but outside the metal. this even for frequencies around 50 hertz. Thank's
  40. G

    Physics of Light/Infrared for Solar Stills Research

    Hi, I am doing my dissertation for Mechanical Engineering on Solar Stills and my mentor has suggested it would be a good idea to research the physics of light/infrared absorption, transmission, water evaporation and condensation. I am wondering if anyone has good book recommendations for me to...
  41. G

    Is This Transmission System Exercise Correctly Solved?

    Homework Statement We have a transmission system (plate-pinion), with a 38-tooth chainring and a 14-tooth sprocket. The distance between the crank (between the chainring and the pedal) is 170 mm and the pedal is overloaded with 60 kg and pedalled at a speed of 70 min-1. Homework Equations P =...
  42. M

    Light wavelength transmission through ice

    I am studying hailstones. I have set up an experiment to pass colored light through hail, one color at a time for the colors of the visible spectrum, Red, Orange, Yellow, Green, Blue, Indigo and Violet (ROYGBIV). I have measured the dominate wavelength for each color with a photo spectrometer...
  43. gfd43tg

    Preserving Vehicle Transmission in Park

    Hello, From what I understand, when you put your car from Drive to Park, you put stress on the transmission. I have been parking in the following order: Use Parking Brake -> Put car into neutral -> Put car into park. Is this the best way to preserve my vehicle's transmission? Or is there a...
  44. C

    Underwater acoustics: transmission loss at long distance

    Hi all, I have some problems to understand how to calculate the transmission loss at long distance, which model do I have to use? I was looking into the energy flux model (Weston model), but I didn't understand at what range I should switch from "mode stripping" to "single mode". I am working...
  45. maxelcat

    Transmission Grating: Determining the Correct Order of Diffraction

    Homework Statement This is a question we have been doing at school. The answer is C. I think A is correct as well. Homework Equations I have used nλ=dsinθ and put in test values. I guess I should be able to do this by just 'inspecting the question' but the sin confused me. So I put in some...
  46. g98

    To reduce cost and weight, power transmission lines are made

    Homework Statement Determine the resistance of a 30 km long wire. b. Assume that the line transfers 1000 MW of power at a potential difference of 500 kV. What is the current through the wires? c. How much power is lost during transmission? What fraction of the transmitted power is lost...
  47. A

    Lattice Diagram of a transmission line

    In lattice diagram, if the voltage wave is generated at Junction that there is an overhead transmission line before it, will the wave be in two directions with the same magnitude, or one in neglected ? Picture may illustrate .
  48. T

    Why do radio transmission harmonics occur?

    What I understand about harmonics, is when something is transmitted at high power, the antenna resonates on other frequencies besides the desired one. But Why?
  49. R

    Coupling signals to a stripline transmission line

    Hello. I have a question about the place where signal enters or gets out from a line (strip or not) Sorry I don't know the exact word in english, may be tap or tapping ... For different lines 1/4 or 1/8 wavelength these points are sometimes @ a 1/4 from the cold point, sometimes elsewhere. I...
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