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Siemens Overload Relay: Thermal Protection, 3 Poles, 1NO/1NC, Frame Size S0 - IEC Thermal Overload Relays
SiemensIEC Thermal Overload Relays

Siemens Overload Relay: Thermal Protection, 3 Poles, 1NO/1NC, Frame Size S0

The SIEMENS Overload Relay: Thermal Protection is an IEC thermal overload relay in Frame Size S0, designed for use with SIRIUS contactors of the same frame size. It features a 1NO/1NC auxiliary contact form, screw…

SKU 3G-OTH-41215

Brand
Siemens
Item
Overload Relay: Thermal Protection, 3 Poles, 1NO/1NC, Frame Size S0
Category
IEC Thermal Overload Relays
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Technical Specifications

Siemens
Manufacturer Part Number
3RU21261KB0
Type
1NO/1NC, Frame Size S0, 9 A – 12.5 A
Poles
3
Frame Size
S0
Compatible Contactors
Frame Size S0
Auxiliary Contact Form
1NO/1NC
Maximum Voltage Rating
690V AC
Phase Loss Sensitivity
No
Thermal Units Required
None (Relay Includes Integrated Bimetallic Elements)
Terminal Connection Type
Screw Terminals
Compatible Contactor Series
SIRIUS
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Siemens Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The SIEMENS Overload Relay: Thermal Protection is an IEC thermal overload relay in Frame Size S0, designed for use with SIRIUS contactors of the same frame size. It features a 1NO/1NC auxiliary contact form, screw terminals, and a maximum voltage rating of 690V AC. The relay includes integrated bimetallic elements, eliminating the need for separate thermal units, and does not offer phase loss sensitivity.

Frequently Asked Questions

What is the SIEMENS 3RU21261KB0 overload relay used for?

The SIEMENS 3RU21261KB0 is an IEC thermal overload relay used to protect motors from overcurrent and phase imbalance. It is designed for use with SIRIUS contactors in Frame Size S0, making it suitable for industrial motor control applications in pumps, conveyors, and compressors.

What are the specifications of the SIEMENS 3RU21261KB0 overload relay?

The SIEMENS 3RU21261KB0 is a thermal overload relay with Frame Size S0, 3 poles, and a current range of 9 A to 12.5 A. It has a 1NO/1NC auxiliary contact form, screw terminals, a maximum voltage rating of 690V AC, and integrated bimetallic elements. It does not include phase loss sensitivity.

Where to buy the SIEMENS 3RU21261KB0 overload relay worldwide?

You can source the SIEMENS 3RU21261KB0 overload relay through 3G Electric, a global industrial equipment distributor. We handle full logistics, customs clearance, and delivery to worldwide destinations. Contact us for availability and lead time.

How to install the SIEMENS 3RU21261KB0 overload relay?

Mount the SIEMENS 3RU21261KB0 directly onto a SIRIUS contactor of Frame Size S0 using the screw terminals. Ensure the motor current is within the 9 A to 12.5 A range. Wire the 1NO/1NC auxiliary contacts for alarm or trip indication. Follow standard IEC installation practices and verify torque settings.

Used in

Common applications for Siemens
District cooling plants — LME73 + RWF55 for condenser-water modulation
Inflight catering and food-processing steam boilers — LMG22 with SQN90 air-fuel cross-damper
Hospital steam-plant redundancy — LME41 with QRA2 UV flame detection for dual-fuel boilers
Semiconductor fab process heat — LME23 and SKP55 gas valves on hot-oil heater skids
Container-terminal reefer-deck heating — LMG22 retrofit onto legacy burner racks

Siemens Products

3G Electric supplies Siemens iec thermal overload relays. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

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