SIEMENS 3AH3 series vacuum circuit breaker

SIEMENS 3AH3 series vacuum circuit breaker

Core features and structure of the product

1. Core design and maintenance free advantages

Vacuum arc extinguishing system:

The arc extinguishing chamber adopts air insulation, which can be freely contacted and the insulation components are easy to clean in harsh environments;

The upper bracket of the arc extinguishing chamber is fixed, the lower bracket is axially guided, and the supporting components absorb external forces and contact pressure during opening and closing;

Maintenance free cycle: Under normal conditions (IEC 62271-1), it supports 10000 operating cycles without lubrication or adjustment.

Spring energy storage operating mechanism:

Energy storage method: electric energy storage (standard, motor voltage 24-240V DC/AC) or manual energy storage (with dedicated handle, order number 3AX15 30-4A/B/C);

Opening and closing control: remote electric (closing soleoid voltage 24-240V DC/AC), local mechanical/electric (to prevent accidental closing, switch equipment interlock needs to be connected);

Operation sequence: Supports standard sequence O-3min-CO-3min-CO (normal current), CO-30min-CO (short-circuit current), and some models support O-0.3s-CO-15s-CO (≤ 31.5kA).

2. Key functions and safety design

Free release mechanism: in accordance with IEC 62271-100, when receiving a disconnection command during the closing process, the contact immediately returns to the disconnection position and remains in place to avoid continuous disconnection ("pump effect");

Interlocking system:

Electrical interlocking: The auxiliary contacts of the circuit breaker control the electromagnetic lock of the isolation switch, which can only be operated when the circuit breaker is opened;

Mechanical interlocking: detecting the position of the circuit breaker through sensors to prevent on load opening and closing, and adapting to drawer type components;

Release signal control: When the NO contact is opened, it instantly closes, triggering the alarm system. Local control requires a series cut-off switch (distinguishing between automatic/manual opening).

Technical parameters and environmental adaptation

1. Core electrical parameters (classified by voltage level)

Voltage level Rated lightning impulse withstand voltage (kV) Rated short-time power frequency withstand voltage (kV) Rated short-circuit breaking current (kA) Rated normal current (A) Pole distance (mm)

7.2kV 60/75 20/32 50/63 1250-4000 210/275

12kV 75/95 28/36 50/63 1250-4000 210/275

17.5kV 95/110 36/42 50/63/72 3150-8000 275/300

24kV 125/145 50/60 50/63/72 3150-8000 275/300

36kV 170/185/195 70/85/95 31.5/40 1250-4000 350

40.5kV 185/195 85/95 31.5/40 1250-4000 350

2. Environmental and installation restrictions

Climate environment: Complies with IEC 60721-3-3, with specific levels as follows:

Key requirements for environmental type level

Climate environment 3K4 low temperature -5 ℃, humidity ≤ 95%/day, ≤ 90%/month

Biological environment 3B1 is free from mold and insect erosion

Mechanical environment 3M2 anti vibration and impact

Chemical active substance 3C2 is resistant to slightly corrosive gases (without freezing/wind blown precipitation)

Mechanical active substance 3S2 requires regular cleaning of insulation components

Elevation and insulation correction:

When the reference altitude is 1000m, the insulation level needs to be corrected according to the altitude coefficient K a, with the formula: U ≥ U 0 × K a; Example: At 2500m, K a=1.2. If a 75kV lightning impulse withstand voltage is required, a 90kV reference insulation level should be selected.

Current carrying capacity: The reference temperature is 40 ℃ (for open type switchgear), and the rating can be increased when the temperature is below 40 ℃. For example, the carrying current of 6300A can be increased by about 15% at 20 ℃ (refer to the current temperature curve in the document).

Selection and Configuration Rules

1. Order number structure (16 digits)

Main circuit section (4-8 bits): Define voltage, short-circuit breaking current, rated current, pole spacing, for example:

3AH3 305-6:3 (main group), A (subgroup), H (series), 3 (version), 305-6 (36kV, 40kA, 2500A, 350mm pole spacing);

Secondary equipment section (bits 9-16): Define the combination of release devices, operating voltage, and auxiliary switches, for example:

9-position (release): A (1 shunt release), M (2 shunt releases+1 undervoltage release);

10 positions (closed soleoid): B (24V DC), F (220V DC), K (230V AC);

Option code: End with "- Z" and add a 3-digit code (e.g. Z A20:64 pole plug gold-plated).

2. Core options and auxiliary equipment

Option Category Model/Code Function Description Applicable Scenarios

Automatic tripping device with shunt release (connected to protective relay, 24-240V DC/AC) for overcurrent protection

When the undervoltage release voltage is less than 35% of the rated value, the circuit breaker (24-240V DC/AC) provides abnormal voltage protection

Current transformer operation release without auxiliary power supply, time division switch (0.5/1A rated current), remote and no power supply scenario

Auxiliary switch 6NO+6NC standard, providing regular control requirements for opening and closing status signals