What is Back EMF & what is its significance | DC Motor | TheElectricalGuy

[@kennedymwila2100]

I clicked on the video by mistake. But I have really enjoyed the lecture. Well done

[@GauravJ]

Glad you liked it 👍🏻

[@mariastanford5701]

@@GauravJ due to Back EMF magnetic field strength of stator's electromagnet(DC motor) also reduced? Lets say stator required 1 amp to produce B=0.2T, but due to back emf if its only consume 0.5Amps, Does B=? also get reduced?

[@aliusef2912]

best explanation ever existed on DC motor starting current & back emf.

[@GauravJ]

Thank you 😊

[@ritas20]

Great explanation, well done!

[@GauravJ]

Glad it was helpful!

[@sisir22]

your lecture is very helpful to know the working principle of DC motor. thank you sir.

[@GauravJ]

You are most welcome

[@boffotape914]

Very clear and neat explanation .

[@sisir22]

sir you are sparking the mind what we want to digest. ok so creative idea.

[@karthik77-5]

So what about whent it comes to a DC Generator, the back emf reduces the magnetic field like the back emf reduced the effect of supply voltage here?

[@sanihabegum1086]

I think that, as the electrical energy is the output of a generator, there is no source which the armature field is opposing. The emf produced from the armature flows through the commutator and is received as the output through brushes. Furthermore, the field produced by the armature is opposing the source current in a motor, whereas in a generator, there is no source to oppose

[@karthik77-5]

@@sanihabegum1086 ohh thankyou for clarification..😃

[@showmikalves5430]

It was helpful...Thank you

[@trader573]

Interesting video indeed..🔥💯

[@davem5392]

I think loosing the field while motor is running has big consequences related to this. Also if no field motor will not rotate I think it would be useful for you to explain this

[@uniquebeats5378]

More videos on dc Machines please ------ load characteristics

[@GauravJ]

Hello. I have a detailed course on DC machines.. you can check it out. Link is in the description

[@SumaiyaFerdous-p2j]

Then why don't we supply source of less voltage? Considering the capability of the motor? Plz answer if anyone knows.. Thank you

[@TanjilKabir]

Every motor is designed to operate at a specific rated voltage. While reducing voltage might seem like a way to prevent high back EMF or protect the motor, it generally results in poor performance, reduced efficiency, and potential damage due to higher current draw. Why? Because lower voltage resulting less speed and in this condition B-EMF is negligible , so at the starting of the motor, it will draw a large amount of current .Therefore, motors are typically supplied with their rated voltage to ensure optimal operation.

[@TcTDezaster]

Back EMF is a function of the angular velocity or rotational speed. Reducing voltage will decrease the speed of rotation and therefore . But yeah the motor is now slower

[@Who_was_That.]

Thanks

[@ramswaroopkhokhar7910]

Is back emf existing in AC machine ??

[@a1kyam]

Thank you very much sir ❤

[@GauravJ]

Most welcome

[@danblankenship5744]

I agree, if your motor employs a magnet and a coil of wire your motor will induce a back EMF. Unfortunately, this back EMF will significantly inhibit the output power from your motor. If you have a 12Volt DC motor, you could expect the motor's output power is being created from about 3 Volts while the back EMF is consuming the other 9 volts. So your opening statement, "If the back EMF is not there it could damage the motor ..." is a little misleading. Without back EMF the same motor would be rated as a 3 volt motor and it would be just fine. If you went ahead and applied the old 12 volts, then your statement is true. With a geometry change a DC motor can be created without these powerful magnets that induce this counter productive EMF. From what I've seen, the efficiency of such creations leave the existing motors in the dust. The closest thing I have found are generally classified solenoid engines.

[@Ustad-p3z]

what will happen if we connect dc motor to dc source via diaodes

[@vipinthampy4669]

Please do vedio on solar cell

[@abdulqayyum4715]

Sir. What is fee of course of electrical for 6 months in Pakistani rupees?

[@GauravJ]

Hi. You can check it on courses.theelectricalguy.in

[@mahershhab3824]

احتاج مساعده بمقابل مادي لو سمحت

[@DaniyalAshraf-ce4rr]

You have explained the eddy currents not the back emf

[@davidopperman6117]

Initial current won't be 50 amps because the coil has reactance

[@JONASDJORBUAHTETTEY]

If back emf is for DC motor what do we have in AC motor

[@infinitebeing1119]

Back EMF present in both AC and DC motors.

[@engrnaveed96]

Best

[@sowmijadeja]

what happens if Back EMF = Supply Voltage ?

[@AsifMPED]

Armature current will become zero, and therefore electromagnetic torque will also become zero.

[@CaryS2]

To say that is why back emf is of paramount importance is insufficient. How about saying WHY back emf is important to have or not have specifically.

[@Sam-yq3br]

Very good lesson though the accent is hard to be understood by Chinese...

[@honestman276]

Despite that comment, I thank you much. Thanks from Bangladesh.

[@mahershhab3824]

I need some paid help, please

[@nkotoki]

what you are talking about is electricity only you can understand.

[@mr.elliotanderson]

whatever you told could be told in 5 minutes itself ...

[@mr.elliotanderson]

whatever you told could be told in 5 minutes .....why you taken so long

[@nicoledarling3538]

Very low on visual aids. You don't explain how to calculate back EMF on any system nor do you show nor the relation to speed and back EMF... Videos should be used to make information visual, not just to lecture.

[@Traderhood]

Why don’t you make one yourself then.

[@bernardocisneros4402]

Very good video. Thank you! I have a question. I'm just getting started in electronics so I'm having trouble understanding the relationship between back EMF and inductive reactance. I assume back EMF is not the same as inductive reactance, but both work together in an AC circuit to oppose the flow and change in current. My question is: Are back EMF and inductive reactance the same thing or does back EMF oppose the change in current while inductive reactance opposes the flow of current?

[@GauravJ]

No. Back emf and inductive reactance are not the same. Back emf does not oppose the current.

[@bernardocisneros4402]

@@GauravJ Thanks for the quick reply. I think I understand now. Back EMF opposes the supply voltage and that's why you subtract back EMF from supply voltage when calculating current with Ohm's law, but by increasing back EMF or inductive reactance you decrease current. Is this correct? If not, please recommend one or more of your videos that might clear this up for me. Thanks again!

[@GauravJ]

Yes, back emf opposes the supply voltage. That is correct. Now, inductive reactance will not come into picture in case of a dc motor. Inductive reactance is only applicable for AC (Alternating current) as it only opposes the change in current and not constant current (DC,). To have more clarity on it, you can check out my playlist on "AC circuit"

[@bernardocisneros4402]

@@GauravJ Thanks for the explanation. I understand it now. Formula for inductive reactance is 2pifL and frequency in DC cicuit is zero so if you plug in zero for frequency in the inductive reactance formula the product is zero.

[@yarasinikitha8972]

Loved the vd❤

[@honestman276]

Your own statement about the definition and functions of different terms confuse us. Please don't misunderstand me. Thanks from Bangladesh.

[@rmanobalaji6475]

Thanks