Abandoned high voltage discharge capacitors

Will a capacitor hold a charge if disconnected?

In theory it will. If an ideal capacitor is charged to a voltage and is disconnected it will hold it's charge. In practice a capacitor has all kinds of non-ideal properties. Capacitors have 'leakage resistors'; you can picture them as a very high ohmic resistor (mega ohm's) parallel to the capacitor.

Which discharge device should be used for capacitors?

Resistors are the preferred discharge device for capacitors though reactors and voltage transformers can also be used if faster discharge is necessary. By using resistor, the rate of discharge, resistor power dissipation can be controlled to a high degree by the designer.

Can a power capacitor be discharged?

For most power system switching applications, once the voltage is decayed below 10% it is typically safe for reclosing, switching etc. The most common method of power capacitor discharge is to permanently connect resistors across the terminals.

When should a capacitor be discharged?

I'm in charge of designing the discharge circuit, in which I have an input that indicates when I want to discharge the capacitor. When the input is 0 V, the discharging circuit should be closed so when the car turns off (or fails) it should be discharging.

What type of capacitor is used in a DC-DC converter?

In designing a relatively high voltage DC-DC converter, my output capacitor happens to be a 100uF electrolytic charged to 400v nominal. Efficiency is a design constraint, so I would like to know of any common design practices that handle the discharging of these capacitors.

What happens when a capacitor is disconnected from a power source?

When capacitor is disconnected from power source, an auxiliary relay connects capacitor terminals to resistor ‘r’ dissipating the charge across the resistor. See figure 3. Resistor ‘R’ is the built-in discharge resistance of the capacitors which is typically of high ohmic value.