How do Universal Motors work ?

How do Universal Motors work ?

Universal Motors they are capable of running under both DC and AC power supply this unique feature makes them preferable for many special types of applications a universal motor is a specially constructed DC series motor let’s consider a simplified series motor when connected to a DC power source they work just like a DC motor with the help of commutator rings a unidirectional current is always made to flow through the left and right side of the coil thus the torque action is always unidirectional and the rotor continues to rotate let’s see what happens when the same motor is connected to an AC power source since the field coil and rotor coils are connected in series the same phase of electricity passes through them always it is obvious that in this case the electricity flow through the left and right part of the coil is never unidirectional but along with the change in direction of this current direction of magnetic flux also changes as the same electricity flow through field and rotor coils this simple trick will make sure that the torque action is always unidirectional here are the different scenarios that could occur during the motor rotation you it is clear that irrespective of speed of the rotor and frequency of electricity the torque action is always in the same direction as a result the rotor will continue to rotate even under an AC power source but if you connect an ordinary DC series motor with an AC power supply it won’t perform well you have to make some modifications on it since the AC power produces a fluctuating magnetic field eddy current loss in the core will be heavy for this reason the core layers should be laminated for a universal motor during the AC operation the transformer action induces an EMF and extra sparking at the brush contact thus the contact brushes of a universal motor have to be of high resistance we hope you had a nice introduction on the working of universal motors thank you for watching the video

75 Replies to “How do Universal Motors work ?”

  1. Great video, very explanative, though I'm wondering why you chose the Left-Hand rule? Traditionally the Right-Hand rule is used, and although they're equivalent (as long as you swap the current/magnetism fingers), it's kind of confusing. I paused the video for several minutes wondering how come my RHR wasn't matching your diagram, till I realized what was going on.

  2. Is there back EMF with universal motor , I want regenerative braking  on heavy electric assist velomobile , permanent magnet dc or electro magnet for simple low power dc generator suitable for low dc battery charging…thanks for your time  

  3. Could you please do a video on how the motor that turn the blades of the quardcopters work. I have a theory for a new quardcopter motor but I before I say it I want to see if that motor would work.

  4. I think the positon of the electric brush should be delicately designed, or else there would exist some time during the rotation that the torque is dragging the rotor.

  5. Might this have anything to do with why my vacuum cleaner motor has loads of sparks coming out, with a burning smell?
    And will replacing the brushes help?

  6. so, while operating in dc, if i swap the polarity at the brushes the rotor will rotate in the opposite direction but what about while in ac? does it work the same way?

  7. I tried using the transvestite over the forward converter but it burnt the 3GPP transistors. Does anybody know where I can find a jar of pickles for my pulse code Modulator?

  8. hi, I need a help to understand how work this motor. When you used the left rule hand, do you indicate the real direction of current? Tks for your help 🙂

  9. man…i just dont have money to fix my dremel tool…now i gotta learn electric stuff and engineering??! augh this is cool stuff but i feel like im back in school….well atleast this knowledge might actually have a practical application


  11. Good Work Learn Engineering Team. Can you please make a video on "Why DC shunt motor cannot be used as Universal motor"?

  12. OK so we have a 120v ac motor at 1200w. Something went out. Either the X2 safety capacitor 10%, film capacitor 2J473J, or the Tip transistor. Which Tip transistor is it? TIP120 TIP122 TIP125 TIP31 TIP32 TIP41 TIP42?

  13. Fcking Hell, I jumped on the start of the video like an AC 3 Phase motor with full torque at the start of the video…lol… "Universal Motor BOOOO"

  14. When we give ac supply to dc motor the motor will burn due to absence of reactance universal motor how we use same winding for both ac and dc supply.

  15. Your channel will have more subscription if you will also provide your videos in Hindi language
    Your animations are good but many Indians find it difficult to understand .

  16. If universal motors are dc series motor, then series motor are types of motors which should not be run without a load or run ta dangerously high speed damaging the motor,

  17. some thoughts, for commenters. the word 'series' describes the way in which power is routed through the system (the motor). this type of motor has NO magnets. the 'field' is produced by two electromagnets (connected in series) which are energized via the Commutator. the field coils and the armature windings are in a Series circuit. the Commutator completes the circuit (via its switching action) and must be of a specific config. googletranslate note the discussion/images at 'generators'

  18. One advantage of these motors is that they can spin at extremely high speeds, tens of thousands of rpm for some types. AC induction motor speeds are determined by the number of poles and power line frequency. Two and four pole induction motors spin at 3450 and 1725 rpm respectively for 60 Hz power. A vacuum cleaner motor may spin at 10,000 rpm, thus allowing a small fan to produce powerful suction. A wood router may spin at 25,000 rpm.

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