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LRD-21

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Overview of Siemens LRD-21 Thermal Overload Relay

The Siemens LRD-21 is a thermal overload relay designed to provide reliable motor protection by preventing damage from overload currents. Adjustable for current settings between 12 to 18 A, it offers phase loss and phase unbalance detection with a Class 10A trip characteristic according to IEC 60947-4-1 standards. This relay is suitable for use with compatible Siemens and Schneider Electric contactors, ensuring efficient motor control in industrial applications.

Key Features

  • Adjustable current range from 12 to 18 A for precise motor protection.
  • Phase failure sensitivity with tripping at 30% of rated current for one phase lost.
  • Thermal Class 10A trip characteristic for standard motor overload protection.
  • Manual or automatic reset options for operational flexibility.
  • Isolated Normally Closed (NC) trip contact and Normally Open (NO) alarm contact.
  • Red stop button for manual motor stop operation and blue reset button for quick resetting.
  • Suitable for a mounting system compatible with LC1D09 to LC1D32 contactors.
  • Wide operating temperature range from -20 to +60 °C.
  • Protection rating IP20 and conformity with IEC 60529.

Technical Specs

Specification Details
Model LRD-21
Current Setting Range 12 to 18 A
Trip Class 10A (IEC 60947-4-1)
Phase Failure Sensitivity Trip at 30% In on one phase lost
Trip Contact 1 Normally Closed (NC)
Alarm Contact 1 Normally Open (NO)
Reset Manual or Automatic
Mounting Compatibility LC1D09 to LC1D32 contactors
Operating Temperature -20 to +60 °C
Degree of Protection IP20
Insulation Voltage Up to 690 V
Impulse Withstand Voltage 6 kV

Applications / Use Case

Ideal for the protection of three-phase motors in industrial and manufacturing environments. It safeguards motors against overload and phase faults, ensuring reliable operation and extended motor life.

Siemens offers robust quality and compliance with international standards for safe and effective motor protection.

LRD-21

$0.00

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Does it come with a warranty?

Yes, All products are offered wth 1-Year warranty.

What is the condition of the product?

All products sold are New & Unused.

How fast is shipping?

All products are delivered within 2-8 business days depending on our stock location.

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