New Industry Products

LEMO Expands its M Series with High-power Connectors

April 13, 2022 by Gary Elinoff

Developed to satisfy the stringent requirements of high-torque applications, the new ratchet-coupling offerings can handle currents of up to 430 A.

The rapid adoption of electric vehicles (EVs), whose battery capacities now often exceed 100 kW, has created a need for cable connectors able to handle increased power demands. Amidst that backdrop, LEMO recently announced an expansion of its field-proven M series of connectors with new, rugged, high-power editions. 

Entirely waterproof, oil and fuel-resistant, high in shock and vibration resistance, and escnonced in a wide range of available bodies for differing settings, the company's new High Power connectors are designed to weather the demanding environmental conditions found in the electric drives of modern EVs and hybrids. 


LEMO's high-power connectors are entirely waterproof. Image used courtesy of LEMO


Suited for mission-critical solutions, the fresh connectors can accommodate conductors ranging from 10 mm2 (8 AWG) up to 50 mm2 (1 AWG). They are available in multiple unipole and multipole configurations, to adapt to both single and three-phase requirements. 


M Series Shells, Enhanced 

In building its high-power connectors, LEMO based their design on the shells of its previous M series offerings. The company developed new insulators and added gold-plated, copper crimp high-power contacts, which it says are state-of-the-art. 

The contacts were designed to maximize contact surface, enabling higher current-carrying capacity while minimizing heat buildup. The low contact resistance limits joule heating; Low mating force is required, and mating cycle durability is specced at better than 3,000 connections. The devices also provide increased surge protection. 


LEMO says its new gold-plated, copper crimp high-power contacts are state-of-the-art. Image used courtesy of LEMO

The end result, LEMO claims, is a connector that offers the highest power through the smallest form factor on the market.  For further information, the company details its entire M series in its comprehensive catalog; Coverage of the new high-power connectors begins on page 21.


The Ratchet Coupling System

The connectors require a 270° turn to effect locking, enabling full socket mating with just a single hand movement. The triple start thread allows for fast nut engagement in the socket, and stable thread engagement eliminates the possibility of a tilted connection.


Mating the connectors requires just a single 270° turn. Video used courtesy of LEMO


To further ensure secure mating, even in high-vibration environments, there is a spring-loaded ratchet on the locking nut. Hand torquing force is all that’s required to securely mate the connector to the socket — no tools are needed. 


Other Key Features 

  • The series includes variations with current ratings ranging from 140 to 430 A
  • The connectors undergo 360° screening for full EMC shielding
  • Resistant to fuel and oil
  • Vibration and shock-resistant
  • Reverse gender configuration available
  • Wide range of lightweight aluminum shell models
  • Connectors are available in brass housing, for 100 hours of salt fog resistance



  • EVs
  • Aerospace
  • Industrial applications
  • Defense
  • Robotics
  • Drones


Environmental Compliance

  • UL-recognized
  • Reach-compliant
  • RoHS-compliant


Regulatory Notes

  • Tested to MIL Standards (MIL-STD-810F)
  • Threaded option for MIL-DTL-38999M backshell 
  • Rated to IP68 when mated; Unmated IP68 is an option


Physical Considerations

  • The connectors operate over a temperature range of -55 to 200 °C 


Feature image used courtesy of LEMO