Overview
Capacitor switching contactors are designed for both reactive and non-reactive capacitor banks. They feature early make contacts and damping resistors to limit the make current to less than 70 times the rated operational current (Ie), and are protected against contact welding for a prospective making current of 200 times Ie.

Specifications
The contactors are suitable for low-inductive and low-loss capacitors in capacitor banks, compliant with IEC70, IEC831, and VDE 0560 standards. They operate at ambient temperatures up to 50°C and 60°C, with varying rated operational powers and currents based on voltage and type.

Technical Data
Specifications adhere to IEC 947-4-1, IEC 947-5-1, EN 60947-4-1, EN 60947-5-1, and VDE 0660 standards. They support a maximum of 120 operations per hour, with a contact life of up to 400,000 operations for reactive capacitor banks.

Mounting Instructions
Use materials that are difficult to ignite and self-extinguishing near capacitor switching contactors due to potential abnormal temperatures around resistor spirals.

Auxiliary Contact Blocks
Available in various configurations, these blocks handle different rated operational currents and are compatible with contactors from K3-10 to K3-115.

Dimensions and Circuit Diagrams
Dimensions for various models and typical circuit diagrams are provided, including wiring for quick discharge resistors to ensure current does not exceed the rated current of auxiliary contacts.

Contactor Operation
Resistor wires do not heat up during operation as they are not in the circuit. Pre-contacts attenuate current peaks during make, preventing damage to main contacts and capacitors. Contactors can be used where pre-contacts have no function during break, ensuring safety against voltage peaks.

Function and Practical Function
Function diagrams and oscillograms show the attenuation of current peaks by pre-contacts and the subsequent building-up of the main circuit with lower amplitude and frequency.

Specifications
The document compares performance of contactors with and without pre-contacts and chokes. Models include K3-18K and K3-18A (12.5kVAr, 18A/400V) and K3-62A and K3-62K (50kVAr, 72A/690V).

Procedures
Describes switching capacitor banks under different conditions, highlighting differences in current peaks with and without pre-contacts and chokes.

Key Observations
- Without pre-contacts, make current peak can reach 1200A; with pre-contacts, it is 280A.
- Without pre-contacts and chokes, peak can exceed 4000A; reduced to 500A with chokes.
- Chokes and pre-contacts reduce peak to 200A.

Recommendations
Using chokes and pre-contacts is recommended to reduce make current peak and improve sinusoidal waveform by reducing harmonic frequencies.