Motorized Circuit Breaker

The CDADA Motorized Circuit Breaker (MCCB) is an upgraded, high-performance low-voltage electrical protection device engineered specifically for AC power distribution systems. With a rated insulation voltage (Ui) up to 1000V AC and rated operational voltage (Ue) of AC 400V / AC 690V (50Hz/60Hz) with current ratings spanning from 10A to 800A (and up to 1250A in extended frame capacities), the DAM11 AC series provides complete overload, short-circuit, and undervoltage protection for heavy electrical equipment, main busbar feeders, and industrial sub-distribution networks.

Designed for versatile three-phase AC power systems, the DAM11 series is ideal for main power incoming panels, secondary feeder lines, and infrequent starting, operational switching, and protection of three-phase squirrel-cage induction motors. Fully compliant with international electrotechnical standards IEC 60947-2 and GB/T 14048.2, the DAM11 AC MCCB supports both vertical and horizontal cabinet mounting with zero or ultra-short flashover distance, offering electrical contractors, switchboard builders, and distributors a reliable, high-breaking solution.

Core Features & Technological Highlights

The DAM11 Series AC Moulded Case Circuit Breaker integrates advanced electrodynamic contact design, modular arc extinguishing, and flexible digital release technology to deliver outstanding AC circuit safety:

● Current-Limiting U-Shaped Pre-Breaking Mechanism: Equipped with an innovative U-shaped stationary contact. When high short-circuit currents occur in the AC circuit, the mutual electrodynamic repulsion force between the fixed and moving contacts rapidly drives them apart before the mechanical trip mechanism operates, rapidly building arc resistance to clamp peak fault current and reduce thermal-mechanical stress (I²t) on downstream cables.

● Modularized Zero-Flashover Arc Extinguishing Chamber: The de-ionizing arc chute splits, cools, and quenches AC electrical arcs within milliseconds, achieving zero external flashover distance and allowing compact switchgear panel designs.

● Unified 6-Frame AC Architecture: Available across 6 standardized frame sizes (125, 160, 250, 400, 630, 800 type). Sibling series—including standard thermal-magnetic DAM11, residual current breaker DAM11LY/DAM11RT, and intelligent electronic DAM11E/DAM11EY—share uniform external mounting dimensions, panel cutouts, and modular internal accessories.

● Intelligent Electronic Release & Modbus Networking (DAM11E / DAM11EY): Microprocessor-controlled digital release featuring adjustable overload long-delay current (IR), short-circuit short-delay current (Isd), instantaneous tripping (Ii), ground fault protection, and overload pre-alarm (Ip). Built-in Modbus-RTU port enables remote telemetry, remote control, and switchboard door digital display.

● Modular Snap-In Internal Accessories: Complete range of modular accessories (shunt trip, undervoltage release, auxiliary contacts, alarm switches) featuring independent insulation barriers for safe installation.

● Industrial & Marine Ambient Resilience: Rated for operating altitudes up to 2000m, ambient temperature range from -5°C to +40°C (+45°C for marine editions), withstanding high humidity, salt spray, industrial vibration, and 4g earthquake resistance.

Technical Specifications & Performance Data

Electrical and mechanical specifications in full compliance with IEC 60947-2 testing standards:

AC Short-Circuit Breaking Capacity Ratings Across Frame Sizes (IEC 60947-2 at AC 400V / 690V)

Tripping Characteristics & Dial Settings

● Distribution Protection (Standard): Instantaneous trip threshold fixed at 10 In ± 20% for cable and transformer branch protection.

● Motor Protection: Instantaneous trip threshold fixed at 12 In ± 20% to withstand initial AC induction motor starting inrush currents without nuisance tripping.

● Electronic Release (DAM11E): Overload long-time delay (IR = 0.4–1.0 In, tR = 60s), short-delay (Isd = 2–10 IR, tsd = 0.1s), instantaneous (Ii = 1.5–12 In), and pre-alarm (Ip = 0.85 IR).

For Motorized Circuit Breaker applications, the trip characteristics and operating mechanism serve different functions: the trip unit provides circuit protection, while the motorized mechanism enables electrical opening and closing. The required configuration should be selected according to the system design.

Typical AC Applications & Industry Sectors

The DAM11 Series AC Moulded Case Circuit Breaker is designed for heavy-duty low-voltage AC power distribution and motor control:

● Industrial Manufacturing Plants: Main incoming power control panels and sub-distribution feeder lines in automotive, metalworking, chemical, paper, and machinery factories.

● Commercial Buildings & High-Rise Infrastructure: Main distribution switchboards (MDB), floor distribution panels, and HVAC chiller feeder protection in hospitals, shopping malls, and corporate offices.

● Motor Control Centers (MCC): Direct-on-line and soft-starter feeder protection for heavy three-phase AC industrial pumps, blowers, air compressors, and conveyor systems.

● Data Centers & Critical Power Infrastructure: Incoming and outgoing AC feeder protection for UPS systems, backup diesel generator synchronization panels, and PDU distribution units.

● Construction & Mining Distribution: Robust power distribution boxes and temporary site power panels requiring high vibration resistance and reliable overcurrent protection.

● Marine & Port Facility Switchgear: Marine-grade vibration-resistant AC distribution boards compliant with marine ambient standards.

For installations that require remote switching, a DAM11 configuration with the CD2 motorized operating mechanism can also be considered for Motorized Circuit Breaker applications. The choice of operating accessories depends on the control circuit and switchgear requirements.

Standards, Certifications & Factory Quality Assurance

CDADA maintains rigorous factory testing to ensure high quality and long-term durability in every AC MCCB unit:

● Compliance Standards: IEC 60947-2 (Low-voltage switchgear and controlgear - Part 2: Circuit-breakers), GB/T 14048.2.

● Product Certifications: CE Marking (European compliance), CCC Certification.

● Factory Quality System: Standardized quality management with 100% automated calibration and functional testing.

10-Step Factory Quality Control Workflow

● Incoming Raw Material Testing: High-precision electrical conductivity check on copper terminals, contact assemblies, bimetals, and flame-retardant BMC/DMC molding materials.

● Automated Robotic Assembly: Automated assembly of U-shaped fixed contacts, moving contact levers, and de-ionizing arc chutes.

● 100% Thermal Tripping Calibration: Constant-current thermal bath testing to ensure exact adherence to inverse-time overload trip curves.

● Instantaneous AC Pulse Current Test: High-current magnetic and electronic instantaneous trip threshold calibration.

● Dielectric Insulation Withstand Test: 2500V AC insulation test across open contacts, phase-to-phase, and to ground.

● Mechanical Endurance Validation: Verification of 10,000+ mechanical switching operations and automated terminal screw torque checks.

● Outgoing Quality Control (OQC): Verification of laser nameplate, barcode tracking, phase barrier fitting, and master export carton packaging.

For more information about CDADA and its manufacturing background, visit our company profile. You can also browse the full range of moulded case circuit breakers.

Sourcing Advantages & Why Choose CDADA

For international electrical wholesalers, panel builders, and OEM contractors, our direct manufacturing offers clear commercial advantages:

Installation, Wiring Guidelines & Maintenance

Flexible mounting and wiring configurations ensure seamless integration into global standard AC switchgear cabinets:

● Mounting Flexibility: Supports both vertical mounting and horizontal mounting without derating breaking performance.

● Wiring Methods: Front-board wiring (standard bolt connection), Back-board stud wiring (rear connection), and Plug-in / Drawout base mounting for quick replacement.

● Phase Barriers: Interphase insulating partitions must be inserted into the top and bottom slots to prevent interphase flashover.

● Torque Verification: Terminal bolts must be tightened with a calibrated torque wrench in accordance with conductor sizing tables.

● Routine Maintenance SOP: Clean dust from arc chute exhaust vents annually; check terminal bolt tightness; inspect contact wear after clearing fault currents.

Comprehensive Accessory Range & Modularity

The DAM11 Series AC Moulded Case Circuit Breaker series provides a rich selection of factory-fitted and field-installable accessories:

Internal Accessories

● Shunt Release (MX): Remote tripping mechanism upon voltage application (AC 220V/380V, DC 24V/110V/220V, operating range 70%–110% Ue).

● Undervoltage Release (MN): Automatically trips the breaker when supply voltage drops below 35%–70% Ue to protect motors and equipment from brownouts.

● Auxiliary Switch (OF): Provides remote indication of breaker contact status (ON / OFF).

● Alarm Switch (SD): Activates signal contacts only when the breaker trips due to overload, short-circuit, or shunt release.

External Accessories

● Manual Rotary Operating Handle: Direct panel-mounted rotary handle (W) or door-interlocked extended rotary handle (Z).

● Motorized Operating Mechanism (CD2): High-reliability electric motor drive (AC 230V/380V, DC 24V/110V/220V) for remote automatic opening and closing.

The CD2 motorized operating mechanism is the relevant accessory for applications requiring a Motorized Circuit Breaker configuration. It enables remote electrical opening and closing, while the circuit breaker's protection functions are provided by its selected release unit. For compatible accessory options, see our MCCB accessories.

● Terminal Shrouds & Spreader Kits: Extended busbar terminal plates and transparent protective covers (IP40).

● Plug-in Base & Drawout Mechanism: Allows rapid replacement without disconnecting main busbars.

Export Packaging & Shipping Specifications

Heavy-duty export packaging designed for ocean container shipping, air freight, and multimodal transit:

Logistics Compliance: Standard fumigated wooden pallets, stretch-film wrapping, corner edge protectors, clear shipping marks (Model, Current, Pole, Gross/Net Weight, CE/CCC markings).

Frequently Asked Questions (FAQ)

Q1: What is the main operational benefit of the U-shaped fixed contact in the DAM11 AC series?

A1: The U-shaped stationary contact creates a self-generated electrodynamic repulsion force during high AC short-circuit faults. This force separates the moving and fixed contacts milliseconds before the mechanical trip mechanism unlatches, rapidly introducing arc resistance to suppress the prospective peak fault current and reduce thermal stress on the AC electrical system.

Q2: How do I choose between Breaking Classes S, M, and H for AC distribution?

A2: Class S (Standard Breaking, 25–50kA) is suitable for general commercial and light industrial sub-distribution. Class M (Medium Breaking, 50–65kA) is recommended for main distribution switchboards with higher prospective fault currents. Class H (High Breaking, 70–85kA) is designed for heavy industrial installations near transformers and high-capacity power stations.

Q3: What are the differences between 4-Pole Neutral types A, B, C, and D?

A3: Type A: N-pole without overcurrent release, cannot close/open with other poles; Type B: N-pole without overcurrent release, closes/opens with other poles; Type C: N-pole equipped with overcurrent release, closes/opens with other poles; Type D: N-pole equipped with overcurrent release, cannot close/open with other poles.

Q4: What is the difference between Distribution Type and Motor Protection Type releases?

A4: Distribution Type releases are calibrated with instantaneous tripping at 10 In ± 20% for cable and line protection. Motor Protection Type releases have a higher instantaneous setting at 12 In ± 20% to accommodate high AC motor starting inrush currents without tripping.

Q5: What is the Minimum Order Quantity (MOQ) and production lead time?

A5: For standard models in factory packaging, MOQ is 1 master carton (e.g., 12–24 pcs depending on frame size). For customized OEM branding, typical MOQ is 100 pcs per frame size. Production lead time is typically 15–25 days for container orders.

Q6: Can the DAM11 series be configured as a Motorized Circuit Breaker?

A6: The DAM11 series can be equipped with the optional CD2 motorized operating mechanism for remote electrical opening and closing. This configuration can be used in Motorized Circuit Breaker applications where electrical operation is required. The suitable operating voltage and accessory combination should be confirmed according to the switchgear control circuit and application requirements.

Sample Policy, Testing Support & Warranty Terms

● Sample Support: Evaluation samples available for type testing, dimensional fitting, and laboratory validation.

● Standard Factory Warranty: 18-month warranty from date of shipment or 12-month from installation date against manufacturing defects under normal operating conditions.

● Technical Support: Full technical data sheets, 2D/3D CAD dimensional drawings (STEP/DWG), and trip curve diagrams provided upon request.

● Quality Claim SOP: Direct factory replacement for verified quality issues with complete batch traceability.

OEM & ODM Customization Capabilities

We provide comprehensive private label and engineering customization services for global electrical brands:

● Model & Specification Definition: Select frame size (125–800), pole count (3P/4P), breaking class (S/M/H), and trip curve (Distribution / Motor / Electronic).

● Customized Laser Nameplate: High-resolution laser engraving of customer brand logo, custom model codes, QR traceability codes, and certification marks.

● Specialized Voltage & Auxiliary Configuration: Tailored shunt/undervoltage release voltages (e.g. AC 220V/380V/415V, DC 24V/110V/220V for control circuits) and pre-assembled internal accessories.

● Custom Packaging & Multi-Language Manuals: Branded inner color boxes, custom outer export cartons, and localized instruction manuals.

● Pre-Production Golden Sample Sign-Off: Sample verification before full-scale automated batch manufacturing.

Commercial Procurement & RFQ Inquiry Guide

To receive a prompt, detailed quotation within 24 hours, please include the following parameters in your inquiry:

● 1. Product Series & Model: e.g. DAM11-160, DAM11-250, DAM11-400, DAM11-630.

● 2. Pole Configuration: 3-Pole (3P) or 4-Pole (4P: specify Neutral type A, B, C, or D).

● 3. Rated Current & Quantity Breakdown: e.g. 100A (200 pcs), 225A (100 pcs), 400A (50 pcs).

● 4. Breaking Capacity Class: S (Standard) / M (Medium) / H (High).

● 5. Application Type: Power Distribution Protection (Type 1) or Motor Protection (Type 2).

● 6. Required Accessories: Shunt release (voltage), Auxiliary contact, Alarm contact, Rotary handle, Motorized mechanism.

● 7. Installation Type: Front-board connection / Rear-board stud / Plug-in base.

● 8. Branding & Packaging: Standard Factory Packaging or OEM Custom Brand.

● 9. Commercial Terms: Target Delivery Incoterms (FOB Ningbo/Shanghai, CIF destination port, EXW).