What happens if i connect a capacitor in series with a small DC motor (small, battery operated ones)?

Question

will its speed/torque increase?

Answer 1

Since capacitors do not pass DC current, I would not expect the motor to run. If you put it in parallel with the motor it might reduce "noise" in the circuit.

Answer 2

In series not a thing. A capacitor does not carry electricity like a wire would. Picture a bucket. You are pumping electrons into this bucket from the negative terminal of your battery until the bucket is full. Since you are in series the only thing connected to the opening of the bucket is the battery.
Wired in parallel with the motor. You will pump electrons into the bucket and from there they will flow into the motor (when the bucket is full). They will continue to flow through motor, through the other side of the capacitor and return to the positive side of your battery. What the capacitor will do is keep the electron flow through the battery at the same rate even as the battery dies down.
In hydraulics this is called "Accumulator Bottle". It will dapen the spikes or elevate the low points in the voltage flow. Based upon the size of your capacitor.
All a capacitor is is a storage device that does a sudden discharge in power. A battery will maintain a degree of discharge for a longer period of time. This is why capacitors are often used to start a race motor. Using 3 or 4 large capacitors will often start a motorcycle motor and will be less weight than a battery.

Oh by the way something else to consider. If you noticed I said from negative to positive. There are two ways to follow electricity. One is called "Hole Flow" (the traditional way to view it from positive to negative). The other is called "Electron Flow". This is the flow of electrons from the negative battery terminal to the positive. Remember that a battery is nothing more than the electrode shedding an electron and it flowing back to the anode.

Answer 3

If the capacitor is charged up this will increase the voltage to the motor, causing it to speed up for a brief instant until it is charged up in the other direction, at which time the motor will stop as no more current can flow.

Remember when it comes to motor speed and torque, for an ideal motor, speed is proportional to voltage and torque is proportional to current.

Answer 4

Capacitors are used to help with the power spike needed to get a motor turning initially by storing a charge. If it's wired in parallel, you are actually defeating it's purpose and using extra energy for no reason.

Answer 5

I would say it probably do nothing it could run for a second or two untill the capacitor charged.just dependes on how much voltage the motor requires and what size batterie