Automatic Transfer Switch
The MDS9 Series Automatic Transfer Switch is one of the most advanced members of the MDS switch family, offering comprehensive functionality. With a maximum rated current of 4000A, it is suitable for power source end (U-U or U-G) and distribution end load transfer applications. Featuring a withdrawable structure, motorized pre-charging and coil excitation drive mechanism, and dual mechanical interlock switch body, it is equipped with the MC800 controller and a touchscreen LCD panel to ensure more accurate dual power source transfer. The MDS9 Series also includes a bypass type variant (MDS9B Series), which further enhances power supply reliability for critical applications.
Controller Features
Supports various automatic transfer switch control logics: standard type, delayed type, overlapping type, standard bypass type, delayed bypass type, and overlapping bypass type.
21 DI and 11 DO programmable I/O ports to meet diverse customer application requirements.
Real-time self-diagnostic function ensures the device remains in a healthy state with continuous internal scanning and timely alarms for module or ATS faults.
7-inch color LCD touchscreen control panel with multiple functions for parameter display, setting, control, and event logging.
Standard RS485 communication interface supporting Modbus RTU protocol; optional Ethernet interface supporting Modbus TCP protocol for integration with power monitoring or other systems.
The controller does not require an additional power supply and supports an auxiliary third power input.
The processor and digital circuits are isolated from the primary circuit.
Real-time monitoring of three-phase voltage and frequency of two power sources; optional load current detection.
Supports generator start/stop and periodic testing.
Configuration
MDS9S – Withdrawable Standard Automatic Transfer Switch
Suitable for general and mixed load applications. Withdrawable structure facilitates maintenance.MDS9D – Withdrawable Delayed Automatic Transfer Switch
Ideal for motor loads or transformer loads. Withdrawable structure for easier maintenance.MDS9C – Withdrawable Instantaneous Overlapping (Closed Transition) Automatic Transfer Switch
Used for critical loads, commonly in utility-to-generator scenarios. Allows 100ms parallel running of two power sources for “no-break” transfer. Withdrawable design for easy servicing.MDS9BS – Bypass Standard Automatic Transfer Switch
For general and mixed loads. When the main switch is under maintenance, the bypass switch ensures continuous dual power transfer.MDS9BD – Bypass Delayed Automatic Transfer Switch
More suitable for motor or transformer loads. Bypass switch maintains power transfer during main unit maintenance.MDS9BC – Bypass Instantaneous Overlapping (Closed Transition) Automatic Transfer Switch
For critical loads, often in utility-to-generator applications. Allows 100ms parallel operation of two power sources for seamless transfer. Bypass unit ensures continuous transfer during main unit maintenance.
Features & Benefits
Withdrawable structure allows easy maintenance.
Load category: AC-33A, suitable for mixed loads.
Transfer operation time < 100ms.
Neutral conductor has the same capacity as phase conductor, with a dedicated arc chamber.
Dual mechanical interlocks.
Multiple electrical interlocks.
Excellent short-time withstand current and making capacity.
Multiple operation modes: Auto-transfer auto-reset / Mutual standby / Auto-transfer manual reset / Manual / Remote indication / Test.
Multiple control modes: Automatic / Electric / Manual mechanical transfer.
MDS9B Series Features
Consists of two main modules: the automatic transfer switch and the bypass switch.
Main and bypass units can be installed in various combinations (e.g., top-bottom, left-right, front-back).
Bypass switch uses the same mechanical structure and performance as the main MDS9 switch.
Smooth switching between main and bypass units.
Mechanical interlocks prevent misoperation when switching between the main and bypass units.
Technical Parameters & Certifications
Thermal test completed after making/breaking and short-circuit tests per GB/T 14048.11-2016.
Certified to GB/T 14048.11-2016.
Controller certified to CQC1127-2017 Technical Specification for Electronic Controllers for Automatic Transfer Switching Equipment.
Compliant with IEC 60947-6-1, CE certified.
Withstands 1000ms short-time current.
Manufactured in an ISO9001-certified facility.
Product Range
Rated Current: 200A ~ 4000A
Rated Voltage: 120V ~ 600V
Number of Poles: 2-pole / 3-pole / 4-pole
Frequency: 50Hz / 60Hz
Applicable for: Utility-Utility, Utility-Generator, Generator-Generator transfer scenarios.
