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Can you explain why oil filled capacitors must be used for capacitor run motors instead of the more economical ac electrolytic types?

Electrolytic capacitors cannot be used on an AC (alternating current) system.


Why dc can be stored ac cannot stored?

Why direct current (DC) can be stored but alternating current(AC) can not be? Current means flow of charge per unit second. Any flow cannot be made stationary. Then it is not flow. Hence both direct current and alternating current cannot be stored. We can store only charges. In capacitors we store charges and not current. For storing we use direct supply or direct voltage When a capacitor is connected to a battery, which is a source of direct voltage, each plate of the condenser get charged. Charges remain in the plates. No current flows in between the plates. When the source is removed, there are some charges left in the plates. We say that charges are stored in the plates. If an alternating source of supply is connected in between the plates,every instant ,the charges in the plates are alternating and they are not stationary. When ac supply is removed, all the charges move out of the plates and hence no charge is left in them. Hence charges can be stored with dc supply and not with ac supply. However as long as the ac is connected to the capacitor, the capacitor gets stored and emptied with the frequency of the ac supply.


Why capacitors cannot be used with direct current?

DC does not travel through a capacitor for long because there is a buildup of charge on the plates and when the voltage matches the supply voltage, mo more current flows. But capacitors are used to smooth a DC supply because a capacitor acts a bit like a small battery and can prevent any rapid fluctuations in the supply voltage.


How can a capacitor filter the AC and DC?

A capacitor consists of two plates separated from one another by an insulator. These plates are normally thin foil and can be sandwiched around a very thin insulator and wrapped into a small package. Since there is an insulator between the plates, DC connected to the two plates cannot flow as long as you do not exceed the breakdown voltage of the insulator. AC current is a different story. Because the insulator is very thin and the effective plate area is relatively large, a negative charge building up on one plate causes electrons to be repelled from the opposite plate, and as the charge on the first plate reverses and becomes positive, the electrons in the opposite plate are attracted back again. This results in a matching alternating current flow on the opposite side of the capacitor.


Capacitor used in motor for starting torque?

A capacitor builds and holds a charge until required. Larger motors require a temporary boost in electrical power in the start-up phase in order to overcome the inertia of a motionless stator. Once the stator begins to spin, the capacitor disengages from the starting circuit.AnswerCapacitors are used to provide the starting torque for single-phase induction motors. They do this by causing the current through the starting winding to be out of phase with the current through the main winding, causing the resulting magnetic fields to naturally rotate, cutting the bars of the rotor, and inducing voltages into them. The resulting combination of fields provides the starting torque on the rotor. Once the machine is running, this amount of torque is no longer necessary and the capacitor is disengaged. Further to the original answer, the charge on a capacitor cannot 'build up and hold' when subjected to a.c., and most certainly cannot provide a 'boost' -temporary or otherwise!

Related Questions

Is it true that an alternating current passing through a capacitor While a direct current can not Explain?

Then I'll try this. Just as V=IR is the fundamental equation relating voltage, current and resistance for a resistor circuit, the following equation relates voltace, current and capacitance for a capacitor: Or, if you are not familiar with that calculus term with the derivative, you can think of it as: I(t) = C * (change of voltage per time) So when you have DC, there is no change of voltage with respect to time, so there is zero current. When you have an AC voltage signal that varies across the capacitor with time, that equation lets you calculate the current that results through the capacitor. A capacitor is two surfaces near each other, but not touching. A direct current "sees" a capacitor as an open switch. It cannot pass through. An alternating current "induces" a charge in a capacitor and can pass through.


What happens when a capacitor is connected to a dc supply?

is it ? are you sure ? but i know so many circuit where capacitor is connected with ac supply . still , if u connected a capacitor to dc supply , then : 1. if it is in SERIES with the dc supply , it will block all the dc current as capacitor provides infinite resistance to dc current . application : where u want to block dc current.(simple high pass filter) 2. if it is in PARALLEL with the dc supply , it will not block dc current , but if any ac current comes out from the supply , the ac current will go through the capacitor , as capacitor provides small resistance to ac current. application : a) where u want to block ac current.(simple low pass filter) b) to filter the noise (ac components) of dc supply.


Can you explain why oil filled capacitors must be used for capacitor run motors instead of the more economical ac electrolytic types?

Electrolytic capacitors cannot be used on an AC (alternating current) system.


Can dc current pass through capacitor which is in series connection?

No, unless its Voltage rating is exceeded (if it fails, a capacitor acts like a short). In a series connection, only alternating current (AC) can pass, because it will allow the capacitor to discharge sometime. DC will only charge it, as it will not flow the other way.This behavior is useful, actually, when there is need to double the voltage in a circuit. Using transistors, a capacitor is charged, and then discharged into a bigger one (while simultaneously also charging the bigger one with the negative phase of AC, for example). Connect a few steps like this into a "ladder", connect the ladder to a transistor and a transformer, add a few diodes to prevent backflow, and you have yourself a flyback transformer - a device used to generate the high voltages needed to light up a TV picture tube.


Why dc can be stored ac cannot stored?

Why direct current (DC) can be stored but alternating current(AC) can not be? Current means flow of charge per unit second. Any flow cannot be made stationary. Then it is not flow. Hence both direct current and alternating current cannot be stored. We can store only charges. In capacitors we store charges and not current. For storing we use direct supply or direct voltage When a capacitor is connected to a battery, which is a source of direct voltage, each plate of the condenser get charged. Charges remain in the plates. No current flows in between the plates. When the source is removed, there are some charges left in the plates. We say that charges are stored in the plates. If an alternating source of supply is connected in between the plates,every instant ,the charges in the plates are alternating and they are not stationary. When ac supply is removed, all the charges move out of the plates and hence no charge is left in them. Hence charges can be stored with dc supply and not with ac supply. However as long as the ac is connected to the capacitor, the capacitor gets stored and emptied with the frequency of the ac supply.


What does the continuity of capacitor voltage mean?

It might mean that the voltage across a capacitor cannot change instantanteously because that would demand an infinite current. The current in a capacitor is C.dV/dt so with a finite current dV/dt must be finite and therefore the voltage cannot have a discontinuity.


Can resistors stores current?

No, a resistor cannot store current. A capacitor is a passive device that can store a small amount of DC current.


Why the solar panel power cannot be transfer to the meter?

Solar panels are direct current (DC), the electric in the meter is alternating current (AC). You need a special transformer to convert from direct to alternating. This usually has to be done since everything in your house usually runs on alternating current.


Why capacitors cannot be used with direct current?

DC does not travel through a capacitor for long because there is a buildup of charge on the plates and when the voltage matches the supply voltage, mo more current flows. But capacitors are used to smooth a DC supply because a capacitor acts a bit like a small battery and can prevent any rapid fluctuations in the supply voltage.


How ac current pass through capacitor?

Alternating charged current arrives at one terminal on the cap. The load to ground is connected at the other terminal of the cap. Actually 'alternating' can be a confusing electrical term to some folks. Think of the charged current as a wave that delivers this positive current from the bottom to the top of the wave and retreats or falls off at the bottom of the other side of the wave. This condition is caused from the rotating action of the rotor turning inside the stator fields in a generator. The ground through the load is attracted to the positively charged electrons at the barrier of the cap at the top of the wave from the generator. Now. Think charge separation on the ground side. As the electrons become excited on the ground side of the cap at the barrier across from the positive charge (attraction), a vacancy of non-charged electrons has occurred downstream at ground. When the positive charge and current falls at the bottom of the wave from the generator side, the excited electrons at the barrier of the cap on the ground side are now positive (charge separation) and move to power the load and fill the vacancy to ground. This is also the reason for the delay of current and charge moving through a cap to ground. A larger barrier equals a longer delay (faud rating). Nothing but magnetic field attraction between electrons has happened at the cap barrier. This is why a DC current cannot move through a cap. It has no wave. If we pulse the DC, we can get it to move through the cap, but at a lower efficiency than AC. calllowayengines dot com


How can a capacitor filter the AC and DC?

A capacitor consists of two plates separated from one another by an insulator. These plates are normally thin foil and can be sandwiched around a very thin insulator and wrapped into a small package. Since there is an insulator between the plates, DC connected to the two plates cannot flow as long as you do not exceed the breakdown voltage of the insulator. AC current is a different story. Because the insulator is very thin and the effective plate area is relatively large, a negative charge building up on one plate causes electrons to be repelled from the opposite plate, and as the charge on the first plate reverses and becomes positive, the electrons in the opposite plate are attracted back again. This results in a matching alternating current flow on the opposite side of the capacitor.


What type of current must be used with a transformer?

DC current cannot be used in a transformer only AC will work. A transformer needs the continual build and collapse of the magnetic field to keep the iron core from reaching saturation. Only alternating current will transfer power through a transformer.