S3RU Series thermal overload relay

Quick Details


  • Place of Origin: Zhejiang, China (Mainland)
  • Brand Name: suntree/OEM
  • Model Number: 3RU
  • Theory: Thermal Relay
  • Usage: Protective
  • Size: Miniature
  • Protect Feature: Sealed
  • Contact Load: Low Power
  • rated insulation voltage: 660V
  • rated current: 12.5A-630A
  • type: 3UA/LR1/LR2/T/JR20/JR36
  • STANDARD: IEC60947-4
  • Price: Competitive
  • quality: Stable and reliable
  • class: A,B
  • Certification: CE,ISO9001
  • PHASE: 3




S3RU series thermal overload relay are suitable for overload and
phase-failure protection of AC motors with frequency of 50/60Hz,
voltage up to 690V, current up to 0.1-100A under 8-hours duty or
uninterrupted duty.
Several functions provided by these relays, are phase-failure
protection, temperature compensation, ON/OFF indication, Stop
button ,Test button and manual/automatic reset.
Applicable Standards:National Standard:GB14048. International
Standards:IEC609474-1 The relays can be mounted onto contactors
or installed as single units.



Operating conditions


  • The altitude couldn't exceed 2000m;
  • Ambient temperature:-5℃ ~+55℃ and the average temperature no more than +35℃ in 24 hours;
  • Atmosphere:Comparative humidity no more than 50% at max +40℃ , and it may be higher at a lower temperature. The lowest average temperature no more than+20℃ in the wettest month. The maximum average comparative humidity of this month couldn't exceed 90%,The change of temperature leading to dew on the product must be considered;
  • Class of pollution:Class 3;
  • The slope between installation surface and vertical surface couldn't exceed ±5°;
  • Keeping away from explosive, corrosive and electric atomy;
  • Keeping dry;
  • The product should be used and installed at certain place without any shock, vibration etc.





  • Three-phase thermal relays with release class 10A;
  • With differential phase-failure protection;
  • With continuous current adjusting scale;
  • With temperature compensation;
  • With ON/OFF indicator;
  • With TEST (OFF) button;
  • With Manual/Auto reset button;
  • With Auxiliary contacts 1NO+1NC insulated each other;
  • Mounting:plug in connection with contactor or install as a single unit.



Protection characteristics