Micro Drive Solution for Automatic On/Off of Smart Electricity Meters

As the terminal device of the smart grid, smart electricity meters are seeing their automatic reclosing and remote on/off functions gradually become standard. To enable these simple operations, a sophisticated micro-drive system is required. The Φ12 DCM+GEAR UNIT micro geared motor launched by NIDEC COPAL delivers 13N of thrust with only 3V voltage and 1W power consumption, achieving dual-mode automatic and manual control within a compact 12mm form factor.

Working Principle

The working principle of the NIDEC smart meter switch motor (direct-drive geared motor) is divided into two modes: automatic electric drive and manual mechanical operation.

Automatic Function (Auto function)

• Normal Position:​ In the daily inactive state, the motor's output section and button remain at the "Normal position," and the meter is in its normal on/off state.
  
• Electric Trigger:​ When the system requires automatic reclosing or opening, the internal DC motor drives the gearbox (reduction ratio 1:171) to generate direct-drive thrust. The entire output section moves synchronously (The entire output section moves).
  
• Lever Descent:​ As the output section moves, the lever descends and presses the button (When LEVER descends, button pressed), thereby actuating the internal switching mechanism of the meter. The stroke is approximately 2.5mm, with a minimum output force of 13N.
  

Manual Function (Manual function)

• Independent Movement:​ In scenarios such as power failure or maintenance, manual intervention is possible via the external mechanical button of the meter. At this time, only the lever moves diagonally (Only LEVER moves diagonally), while the motor's overall output section does not follow.
  
• Release and Return:​ After manual pressing and release, the lever automatically returns to its initial position relying on the internal mechanical structure (e.g., spring return), ensuring that manual operation does not affect the normal positioning of the motor's automatic mechanism.
  

Practical Application Scenarios

• Structural Correspondence:​ The meter schematic shows the linkage between the external button and the internal motor lever; physical images demonstrate operation via external buttons or manual levers, reflecting the physical integration of direct-drive and manual functions.
  
• Design Advantages:​ This dual-mode design—featuring electric overall direct-drive and a manual independent lever—satisfies the thrust requirements (13N, 1W low power consumption) for remote/automatic control of smart meters, while retaining the convenience of manual emergency operation. At the same time, it ensures that the two modes do not interfere with each other, supporting the life requirements of 10,000 automatic cycles and 4,000 manual cycles.
  

Motor Specifications