Technical
‧ Installation of Capacitor Expulsion Fuse
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‧ Capacitor Expulsion Fuse Unit
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Electrical Properties of Metallized Film
Capacitance Change vs. Temperature
Insulation Resistance vs. Temperature
Dissipation Factor vs. Temperature
MPET: Metallized Polyester Film
MPP: Metallized Polypropylene Film
Self-healing mechanism
Dielectric adopts metallized film as intermediate; in case excessive voltage takes place and damages the material, the metallized layer around the damaged spot will disappear instantly, and insulation is restored immediately.
- Metallized layer
- Film
- Damaged spot
- Self-healing range
Safety
Operation of Internal Safety Mechanism
Capacitor element wounded by segmented metallized film. Hundreds or thousands of small capacitors in parallel formed the element, and each small capacitor equipped individual fuse as Figure 1. When a dielectric breakdown occurred in a small capacitor due to overvoltage, abnormal heating or end of life, the fuse of the failure area burned off and disconnected the failure area from circuit. The remained good small capacitors would continue to be used as Figure 2. Capacitor will not lose the function caused by partial failure. Its self-protective function will prevent capacitor from emitting smoke or catching fire.
Figure 1. Element Structure (Normal Condition)
Figure 2. Fuse burned off on failure area
- Segmented metallized film
- General metallized film
- Metallized layer
- Free margin in transverse direction
- Free margin in machine direction
- Fuses
- Failure area
Operation of Internal Protective Device
In the event of internal failure or aging at the end of the capacitor's operational life, an increasing number of self-healing breakdowns may cause rising pressure inside the capacitor element. To prevent it from bursting, each capacitor element is designed with internal pressure sensitive interrupter (Protective Device). With rising pressure the cover will bulges to disconnecting copper taps at weak points from the cover, and the current path is interrupted irreversibly to avoid the relative disaster.
Contents of Capacptor Technical supports
| Capacitor function | Notices for capacitor installation |
| The benefits of shunt capacitors | References for selections of protective devices for low voltage capacitors |
| The benefits of shunt capacitors at different location | Capacitor maintenance |
| Selection principles of power factor correction capacitors for industrial high or low voltage power system | Calculation of power factor correction |
| Harmonics strategies of power capacitors | General formulas |
| Calculation of resonance point and frequency on capacitors with serial reactors | Calculation of discharging resistor for capacitor |
| Instruction for power capacitors | Features of low voltage power capacitors |
| The causes of capacitor faults | Heat dissipation instruction for induction heating furnace capacitors |
| The effects of lightning strikes on capacitors | Circuit diagram for automatic PFC capacitor banks |
| Correct connection of capacitor for star-delta starting induction motors | The parts and dimensions of expulsion fuses for power capacitors |
