What is Dc motor: Definition and 321 Discussions

A DC motor is any of a class of rotary electrical motors that converts direct current electrical energy into mechanical energy. The most common types rely on the forces produced by magnetic fields. Nearly all types of DC motors have some internal mechanism, either electromechanical or electronic, to periodically change the direction of current in part of the motor.
DC motors were the first form of motor widely used, as they could be powered from existing direct-current lighting power distribution systems. A DC motor's speed can be controlled over a wide range, using either a variable supply voltage or by changing the strength of current in its field windings. Small DC motors are used in tools, toys, and appliances. The universal motor can operate on direct current but is a lightweight brushed motor used for portable power tools and appliances. Larger DC motors are currently used in propulsion of electric vehicles, elevator and hoists, and in drives for steel rolling mills. The advent of power electronics has made replacement of DC motors with AC motors possible in many applications.

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  1. R

    DC motor control progressive start and stop

    hey Everybody!... I`m stck with the Control of a DC Motor...I need To Control a DC motor in this way, it Must Start real slowly, and then progressively but slowly should continue to reach its maximun velocity, it could take up to 1 min to reach it; then remain for a set time stable at its final...
  2. Phrak

    Dynamic Braking of 3-Phase DC Motor

    To brake a 3ph DC, the best I've come up with, apparently, is to place a pair of power FETS, back-to-back across each pair of leads. I would like to manage a hard short without additional load beyond the motor winding resistance, then duty cycle to get controlled braking. As far as having...
  3. T

    Unknown DC motor Specifications

    Me and another person were rummaging through one of my colleges labs looking for usable parts for my groups product design course. We found this medium size motor that weighed about 2-3 pounds. The problem is that there were no stickers at all that indicated its specifications. There were a few...
  4. B

    Calculating the Resistance and Capacitor for a Snubber Circuit with 3HP DC Motor

    Hi, I have build a PWM to control a 3HP DC motor. The problem is that the MOSFET is getting damaged because of high return current/voltage. I used a Diode at the motor end but that diode is also getting burnt. Main DC 380 Volt PWM used to control a 220 DC 3HP motor I found out that a...
  5. K

    Simple Dc Motor Clarrifocation

    So I have a project over the holidays, received it on Friday, I have to build a simple Dc Motor. Using the textbook as a guide has proven to be very difficult becuase it does not explain itself very clearly, I was hoping some one could provide me with some clarrification. Here are the...
  6. dink

    What Is the Best Textbook for Comprehensive Learning About Brushless DC Motors?

    I'm looking for a textbook that has an in depth coverage of brushless DC motor physics as well as control theory. -indepth mathematical approach as well as conceptual theory -controller schemes and design fundementals -mathematical study of induced currents on the stator/rotor, and what this...
  7. T

    DC Motor Circuit: Predicting Vehicle Distance

    So I've designed this simple circuit for an electric vehicle. The inductor and resistor that are boxed off are the motor. The way it works, as you can probably figure out from the diagram, is that the RC circuit on the left controls how long the right side of the circuit runs (via the...
  8. O

    Back E.M.F. & Torque Output of a Permanent Magnet DC Motor

    Hi, What is the effect of "back e.m.f." on the torque output of a permanent magnet d.c. motor? I googled it but didn't get any results.. I just need a brief description to understand the concept.. Thanks :blushing:
  9. B

    Understanding BLDC Motor Control: Position, Speed, and Current

    Hi guys, I'm developing a BLDC motor controller with load. I've bought a Maxon E40 motor . But some things i can't figure out: I want to control position, speed and current (torque). I use PID controller to do it. In the closed loop system the output of the speed controller should be input...
  10. S

    DC motor selection for REALLY low speeds

    Hi everyone. I'm in the process of designing a telescope mount, and am now trying to figure out how to drive the thing. Ideally I would like to go with an off the shelf dc motor and gearhead setup, as this appears to be the cheapest option. My problem is, that I don't know how slowly you...
  11. R

    DC Motor: Rotating Coil in Magnetic Field

    The diagram shows a DC electric motor containing a rectangular coil of 20 turns and of length .50m and width .40m The coil is pivoted so that it can rotate freely on an axle. The coil is shown lying horizontally in a magnetic field of uniform stength .60T. A current of 3.5A is passing through...
  12. T

    Confused with DC motor equations when accelarating

    Hi everyone. I'm trying to build a robotic "arm" to move an object along one axis, the idea is to put a dc motor connected to an H-brigde which is then controlled by a microcontroller, the dc-motor will be attached to the object I intend to move by a cable. Since the objective of this is...
  13. S

    What are the best batteries to power 2 perm 080 dc motors in an EV application?

    i want to power 2 perm 080 dc motors in an EV application, i want to know what batteries will be a good match motor specs-- Typical system performance. Voltage: 24 V Angular-velocity constant: 291 rpm/V Torque constant: 4.64 ozf·in/A Terminal resistance: 0.0236 ohm No-load current...
  14. P

    Eigenvalue for DC motor convergence rate

    Hi, I have troubles solving this question: Given the general DC motor governed equation, find the control voltage such that the speed w tends to constand reference input w* and the convergence rate is determined by the desired eigenvalues L1 and L2. I think it's easy to find the control...
  15. S

    Question about Simple DC Motor Winding

    I have a question concerning the armature in a simple DC Motor, the kind portrayed in textbooks. We have received an assignment to build a DC Motor and while I have made my own design I am having a bit of confusion with the armature. I know I can just have a straight conductor but I was...
  16. Y

    HELPCAN anyone explain the difference between an AC and DC motor?

    i was wondering y there still got some dc motors,coz ac motors more powerful...can anyone tell me y?
  17. L

    DC Motor Speed Control - Ideas & Circuits

    dear members i want to design speed control circuit for 24v dc permanat magnet motor in both direction if anyone have ideas or circuits please post here. it may be great help to me. Thanx in advance
  18. N

    3 Volt DC Motor Performance Graphs

    Does anyone know where I can find 3 Volt DC Motor Performance Graphs on the web? I'm looking for something like this, but with a 3 Volt motor. My googling has yet to find any relevant results. Thanks in advance.
  19. G

    Maximizing DC Motor Performance: Voltage and Amp Considerations Explained

    Hi - can someone please help me with the following - I am mechanically minded not elecrically so please do not pick on me - I purchased a DC motor and gearbox (worm and wheel) from ebay (item 3858047682 if you want to look at it) - now it is supposed to work at up to 20 volts DC - now I was...
  20. I

    Torque in a DC motor (equations?)

    hey, I've been looking EVERYwhere for equations for torque in a DC motor. I've come accorss plenty too: T = µBsinθ and T = k(magnetic flux per pole)I <- where k is a "mechanical and conversion constant" and I is the current in the armature, and i couldnt' find the magnetic flux symbol...
  21. Shahil

    DC Motor Problem - Magnetic Field Calculation

    I really need help in calculating the magnetic field generated by a horse-shoe shaped solenoid which is being used as a permanent magnet in a DC motor. The calculation is VITAL (well, I think so) as I need it to be able to predict the angular speed (in revs per minute) of my motor. If...
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