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Siemens Control Relay: DIN-Rail & Surface Relay Mounting, 125V DC Coil Volt, 2NO/2NC - Combination DIN-Rail & Surface-Mounted Relays
SiemensCombination DIN-Rail & Surface-Mounted Relays

Siemens Control Relay: DIN-Rail & Surface Relay Mounting, 125V DC Coil Volt, 2NO/2NC

The SIEMENS IEC Control Relay is a combination DIN-rail and surface-mounted relay with a 2NO/2NC contact configuration rated at 10 A. It operates with a 125V DC coil voltage (MPN 3RH21221BG40). 3G Electric interprets…

SKU 3G-OTH-37576

Brand
Siemens
Item
Control Relay: DIN-Rail & Surface Relay Mounting, 125V DC Coil Volt, 2NO/2NC
Category
Combination DIN-Rail & Surface-Mounted Relays
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Technical Specifications

Siemens
Manufacturer Part Number
3RH21221BG40
Type
2NO/2NC, 10 A
DC Coil Volt
125V

Technical Documents

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Siemens Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The SIEMENS IEC Control Relay is a combination DIN-rail and surface-mounted relay with a 2NO/2NC contact configuration rated at 10 A. It operates with a 125V DC coil voltage (MPN 3RH21221BG40). 3G Electric interprets this demand and delivers the genuine Siemens part, backed by specialist sourcing across 14 industrial departments.

Frequently Asked Questions

What is the SIEMENS 3RH21221BG40 control relay used for?

The SIEMENS 3RH21221BG40 is an IEC control relay used for switching and isolating electrical circuits in industrial automation, motor control centers, and panel building. Its 2NO/2NC contact configuration and 10 A rating suit general-purpose control applications in manufacturing, energy, and process industries.

What are the specifications of the SIEMENS 3RH21221BG40 relay?

This SIEMENS relay has a 125V DC coil voltage, 2 normally open and 2 normally closed contacts rated at 10 A. It mounts on DIN-rail or surface, with part number 3RH21221BG40. It is designed for IEC control circuits and is suitable for global industrial environments.

Where to buy the SIEMENS 3RH21221BG40 relay worldwide?

You can source the SIEMENS 3RH21221BG40 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 on this part.

How to install the SIEMENS 3RH21221BG40 control relay?

Mount the relay on a standard DIN rail or surface using the integrated clip. Wire the coil to a 125V DC supply and connect load circuits to the 2NO/2NC terminals rated at 10 A. Follow SIEMENS wiring diagrams and ensure proper isolation before energizing.

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 combination din-rail & surface-mounted relays. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

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Compatible alternatives & equivalents

Cross-referenced by specification & description
SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 110V DC Coil Volt, 2NO/2NC, 10 A (MPN 3RH21221BF40)
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SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 110V DC Coil Volt, 2NO/2NC, 10 A (MPN 3RH21221BF40)
SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 125V DC Coil Volt, 3NO/1NC, 10 A (MPN 3RH21311BG40)
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SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 125V DC Coil Volt, 3NO/1NC, 10 A (MPN 3RH21311BG40)
SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 250V DC Coil Volt, 3NO/1NC, 10 A (MPN 3RH21311BM40)
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SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 250V DC Coil Volt, 3NO/1NC, 10 A (MPN 3RH21311BM40)
SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 24V DC Coil Volt, 2NO/2NC, 10 A (MPN 3RH21221BB40)
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SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 24V DC Coil Volt, 2NO/2NC, 10 A (MPN 3RH21221BB40)
SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 120V AC Coil Volt, 2NO/2NC, 10 A (MPN 3RH21221AK60)
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SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 120V AC Coil Volt, 2NO/2NC, 10 A (MPN 3RH21221AK60)
SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 240V AC Coil Volt, 2NO/2NC, 10 A (MPN 3RH21221AP60)
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SIEMENS IEC Control Relay: DIN-Rail & Surface Relay Mounting, 240V AC Coil Volt, 2NO/2NC, 10 A (MPN 3RH21221AP60)

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