# If capacitors are connected in series across a dc source and one of them blows open what will be its effects on output voltage? ?

4 capacitors are connected across dc source, the purpose of the capacitors is to provide emergency supply to motor. In case, one of the capacitor blasts open or short how will it effect output voltage? I searched throughout web to find an answer but didnt find anything on this topic

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• Ash
Lv 7
4 weeks ago

If one of the capacitors blows open then the other 3 capacitors will not get voltage , as the circuit is open . So no stored charge and there will be no emergency supply

On the other hand, if one of the capacitor shorts, then the equivalent capacitance reduces and so does the charge. so you will have emergency supply for lesser time.

(Provided, off course, the 3 remaining good capacitors are rated to withstand the higher voltage across it. )

( Also there may be a possibility that the capacitor may not exactly show around 0 resistance but some little higher resistance causing voltage drop across it. That will reduce the emergency supply delivery too)

• 4 weeks ago

1. The arrangement doesn't make sense.

2. The series string must be in parallel with the output!

3. If one of them opens the voltage remains unchanged but the available current decreases.

4. If one of them shorts the output current increases and the voltage remains unchanged.

• Robert
Lv 4
4 weeks ago

Increase in potential output voltage if the capacitors on the lower side of the total circuit go open as the loading effects of the capacitive divider would be void. If the first capacitor in the series chain goes open there would be no voltage on the series chain except at the full supply voltage tap and across the intact capacitors. The potential voltage from the neutral line would change with the different senarios seen.

• 4 weeks ago

if it shorts it will short out the supply and pop a fuse if there is one, if not, flames will happen.

short is same as cap is replaced by a piece of wire between the two terminals, across the supply.if it opens, output voltage is not effected, but the amount of time the motor will run if power is lost will be reduced. By 1/4th if the caps are all the same value.    open is same as if the cap is removed. But those caps must be of very high value to supply power to a motor for more than a second or two.

edit, sorry, missed word "series"

but why would you put the caps in series.... ??

in series if one blows as a short, the other two are in series. The voltage on each (assuming all 3 are equal value) will go up by 50% which may exceed the rating on those and cause them to die also. C value will increase also.

if one blows as an open, all 3 caps are out of the circuit.