🔔Help Electro Academy grow! 🔔 Your support can make a big difference! 😍 If you appreciate the efforts behind these educational videos, please subscribe - it’s free and just a click away.!🙏🏽 Additionally, if you can contribute, you can become a patron and support our mission of sharing knowledge with students and professionals around the world: patreon.com/ElectroAcademy 🙌 I am deeply grateful to our first sponsor! Your kind gestures motivate us to continue creating quality content. Let’s build this community together.!🏆 THANKS .! - Sudarshan, Creator of Electro Academy
How does the rotor continue running in a rotating magnetic field if the start capacitor disconnects and there is no run capacitor either, because the start capacitor itself was responsible for the stators rotating magnetic field in the first place right?
The rotor continues to run after the start capacitor disconnects, due to an event known as rotational inertia and the residual rotating magnetic field. The start capacitor initially provides the phase shift to create a temporary rotating magnetic field. This is necessary to overcome the initial inertia and produce enough torque to start the rotor moving. Once the rotor reaches a certain speed, the start capacitor disconnects often by a centrifugal switch or a relay. In a single phase motor, the magnetic field is only oscillating rather than truly rotating. By this point, the rotor has gained enough momentum or inertia to keep spinning, even though the magnetic field is only oscillating rather than rotating. There are still enough variations in the field that the moving rotor can “chase” the oscillating field. This interaction continues the rotor’s motion, even if it's less efficient and has lower torque compared to motors with a run capacitor. This design is common in low-load applications where the motor doesn’t need high efficiency or high torque after starting. In cases requiring constant torque and smooth operation, a run capacitor would be used to maintain a steady rotating magnetic field after startup. Hope you got the answer.
What will happen if we use an inductor in place of a start capacitor in single phase induction motor? How could we get an inductor to work as a starter. I would love to see a video answering my question--I believe that this may aid my understanding of both capacitors and inductors.
The reason we don't do that in practice, is that capacitance is significantly cheaper than inductance, per unit of energy storage. So usually when a design is indifferent to a capacitor vs an inductor, the capacitor is preferred. Another reason: the motor winding itself has inductance, which is especially evident at startup. You get a much more significant phase shift by pairing the motor winding with the opposite kind of reactive element, than you would get pairing it with the same kind of reactive element.
If you replace the start capacitor with an inductor in a single-phase induction motor, the motor likely wouldn't start due to the wrong phase shift. The inductor would delay the current in the start winding, preventing the creation of a proper rotating magnetic field. To make an inductor work as a starter, you'd need to redesign the motor entirely, but capacitors remain the preferred choice for most applications because they provide the correct phase lead needed for efficient motor startup.
Exactly. Most single-phase motors require a capacitor to start, especially in cases where moderate to high starting torque is needed. (Compressor motors, pumps, etc.). How ever Shaded pole motors and Split-phase motors are with a different arrangement and can start without a capacitor. But they are limited in their capacity due to very low starting torque and efficiency.
@@ElectroAcademyEA excellent video! I have many questions since I'm in an electrical class at the moment. Do you think you can answer a few of my questions,m
A capacitor is a two terminal thing whose current through it is proportional to the rate of change of the voltage across it. That is , I= C* dv/dt. C just happens to be the “capacitance”. dv/dt is nothing more than the SLOPE of the voltage curve :)
No. I my AC I have 2 x 3uf start capacitors, and the run capacitor is 50uf. But the 3uf caps can be cycled much quicker than the larger one. Lower capacitance means it fills quicker and dischargers quicker. With a start capacitor you're not dumping power like you would in a DC circuit, you're initiating a phase change, So those start caps aren't just dumping once, they're being charged and discharged thousands of times until the motor comes up to 75% of it's speed.
So I have a fountain and capacitor is blow, but wiring doesn't look correct as it has 3 connections from the capacitor but the drawing shows no live feed to the capacitor? Just a neutral in and 2 outputs. Is this correct? Single phase motor
Purpose of the capacitor of a ceiling fan is to create a phase shift between the currents in different windings, generating the necessary rotating magnetic field to spin the rotor. When reversing the fan's direction, the fan motor needs to change which winding is leading in terms of current. By altering the current flow through the windings achieved via an internal switch or control mechanism, the phase shift caused by the capacitor is effectively flipped. This will change the direction of the magnetic field and makes the fan to rotate in the opposite direction.
The pole classification is based on the total number of magnetic poles created by all windings (run and start) in the stator, regardless of how long the start winding is connected. However, when the motor is running, the rotational speed is determined by the number of poles in the run winding and the frequency of the AC supply.
Hello! Please! Would someone explain me how can the voltage be synchronized with current on principal coil? The coil reactance doesn't make current be late compared to the voltage? Thanks...
In an inductive coil, the current naturally lags the voltage due to the coil’s inductive reactance. To synchronize voltage and current (reduce the phase difference), you can add a capacitor to the circuit, which introduces capacitive reactance. This capacitive reactance can counteract the inductive reactance, bringing the voltage and current more in phase. This technique is commonly used in power factor correction to improve the efficiency of systems with inductive loads.
In single-phase induction motors, the capacitor can be connected to either the start winding or the run winding, depending on the type of motor and its design. Capacitor on the Start Winding is the Most Common type. This configuration is typical in capacitor-start induction motors and capacitor-start capacitor-run motors. In these motors, the capacitor is connected to the start winding, which is only engaged during the start-up phase of the motor's operation. If you are focusing on starting torque and the capacitor is meant to help the motor start, it should be connected to the start winding. However If you are focusing on running efficiency and the capacitor is meant to improve the motor's performance during operation, it should be connected to the run winding.
![[#2024MAMA] G-DRAGON - 무제(Untitled, 2014)+POWER+HOME SWEET HOME+뱅뱅뱅+FANTASTIC BABY | Mnet 241123 방송](http://i.ytimg.com/vi/Ox29z5Nf1Uk/mqdefault.jpg)
🔔Help Electro Academy grow! 🔔
Your support can make a big difference! 😍
If you appreciate the efforts behind these educational videos, please subscribe - it’s free and just a click away.!🙏🏽
Additionally, if you can contribute, you can become a patron and support our mission of sharing knowledge with students and professionals around the world: patreon.com/ElectroAcademy 🙌
I am deeply grateful to our first sponsor! Your kind gestures motivate us to continue creating quality content. Let’s build this community together.!🏆
THANKS .!
- Sudarshan, Creator of Electro Academy
nice explanation
Thank you
How does the rotor continue running in a rotating magnetic field if the start capacitor disconnects and there is no run capacitor either, because the start capacitor itself was responsible for the stators rotating magnetic field in the first place right?
The rotor continues to run after the start capacitor disconnects, due to an event known as rotational inertia and the residual rotating magnetic field.
The start capacitor initially provides the phase shift to create a temporary rotating magnetic field.
This is necessary to overcome the initial inertia and produce enough torque to start the rotor moving.
Once the rotor reaches a certain speed, the start capacitor disconnects often by a centrifugal switch or a relay.
In a single phase motor, the magnetic field is only oscillating rather than truly rotating.
By this point, the rotor has gained enough momentum or inertia to keep spinning, even though the magnetic field is only oscillating rather than rotating.
There are still enough variations in the field that the moving rotor can “chase” the oscillating field.
This interaction continues the rotor’s motion, even if it's less efficient and has lower torque compared to motors with a run capacitor.
This design is common in low-load applications where the motor doesn’t need high efficiency or high torque after starting.
In cases requiring constant torque and smooth operation, a run capacitor would be used to maintain a steady rotating magnetic field after startup.
Hope you got the answer.
What will happen if we use an inductor in place of a start capacitor in single phase induction motor? How could we get an inductor to work as a starter. I would love to see a video answering my question--I believe that this may aid my understanding of both capacitors and inductors.
The reason we don't do that in practice, is that capacitance is significantly cheaper than inductance, per unit of energy storage. So usually when a design is indifferent to a capacitor vs an inductor, the capacitor is preferred.
Another reason: the motor winding itself has inductance, which is especially evident at startup. You get a much more significant phase shift by pairing the motor winding with the opposite kind of reactive element, than you would get pairing it with the same kind of reactive element.
Super--thank you@@carultch
If you replace the start capacitor with an inductor in a single-phase induction motor, the motor likely wouldn't start due to the wrong phase shift.
The inductor would delay the current in the start winding, preventing the creation of a proper rotating magnetic field.
To make an inductor work as a starter, you'd need to redesign the motor entirely, but capacitors remain the preferred choice for most applications because they provide the correct phase lead needed for efficient motor startup.
@@carultch Thank you!
Great work, loved it.
Thank you
finally, I catch it! thank you sir
Thank you
This means a single phase is never enough to start a motor and you create another phase with a capacitor.
Exactly.
Most single-phase motors require a capacitor to start, especially in cases where moderate to high starting torque is needed. (Compressor motors, pumps, etc.).
How ever Shaded pole motors and Split-phase motors are with a different arrangement and can start without a capacitor.
But they are limited in their capacity due to very low starting torque and efficiency.
@@ElectroAcademyEA excellent video! I have many questions since I'm in an electrical class at the moment. Do you think you can answer a few of my questions,m
A capacitor is a two terminal thing whose current through it is proportional to the rate of change of the voltage across it. That is , I= C* dv/dt. C just happens to be the “capacitance”. dv/dt is nothing more than the SLOPE of the voltage curve :)
Thanks for your comment
So it means the starting capacitor is bigger than the run capacitor right?
Yes
No. I my AC I have 2 x 3uf start capacitors, and the run capacitor is 50uf.
But the 3uf caps can be cycled much quicker than the larger one. Lower capacitance means it fills quicker and dischargers quicker. With a start capacitor you're not dumping power like you would in a DC circuit, you're initiating a phase change, So those start caps aren't just dumping once, they're being charged and discharged thousands of times until the motor comes up to 75% of it's speed.
So basically, a capacitor start capacitor run motor runs as a two phase motor all the time, both when starting and when running.
Yes.
So I have a fountain and capacitor is blow, but wiring doesn't look correct as it has 3 connections from the capacitor but the drawing shows no live feed to the capacitor? Just a neutral in and 2 outputs. Is this correct? Single phase motor
how can some ceiling fans revert its direction? What is the logic behind the magnetic fields and capacitors that allow this?
Purpose of the capacitor of a ceiling fan is to create a phase shift between the currents in different windings, generating the necessary rotating magnetic field to spin the rotor.
When reversing the fan's direction, the fan motor needs to change which winding is leading in terms of current.
By altering the current flow through the windings achieved via an internal switch or control mechanism, the phase shift caused by the capacitor is effectively flipped.
This will change the direction of the magnetic field and makes the fan to rotate in the opposite direction.
Why is it always the videos with the crazy AI voice that explains it the best?
Concentrate on the content.
Hi there...great video....but tell me...is this a 2 Pole or 4 Pole motor?...
The pole classification is based on the total number of magnetic poles created by all windings (run and start) in the stator, regardless of how long the start winding is connected.
However, when the motor is running, the rotational speed is determined by the number of poles in the run winding and the frequency of the AC supply.
Hello! Please! Would someone explain me how can the voltage be synchronized with current on principal coil? The coil reactance doesn't make current be late compared to the voltage? Thanks...
In an inductive coil, the current naturally lags the voltage due to the coil’s inductive reactance.
To synchronize voltage and current (reduce the phase difference), you can add a capacitor to the circuit, which introduces capacitive reactance.
This capacitive reactance can counteract the inductive reactance, bringing the voltage and current more in phase.
This technique is commonly used in power factor correction to improve the efficiency of systems with inductive loads.
Cap should be on the RUN winding, not the start winding.
In single-phase induction motors, the capacitor can be connected to either the start winding or the run winding, depending on the type of motor and its design.
Capacitor on the Start Winding is the Most Common type.
This configuration is typical in capacitor-start induction motors and capacitor-start capacitor-run motors.
In these motors, the capacitor is connected to the start winding, which is only engaged during the start-up phase of the motor's operation.
If you are focusing on starting torque and the capacitor is meant to help the motor start, it should be connected to the start winding.
However If you are focusing on running efficiency and the capacitor is meant to improve the motor's performance during operation, it should be connected to the run winding.
Sorry sir why starting capacitor is dead many times?
Capacitors also have a general lifetime.
However, If you connect a capacitor of acceptable brand with correct capacity, it will last longer.
A start capacitor always worn out due to on n off it endures when motor is starting n it's subjected to high current on start up of motor LRA.
Correct when you starting motor require high current
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Thank you