The Siemens 3RH2921-1DA20 Lateral Auxiliary Contact Block is a premium-quality control circuit accessory designed to expand the auxiliary contact capacity of Siemens contactors and control relays. As part of the highly trusted Siemens SIRIUS 3RH29 Series, this auxiliary switch block enables engineers, panel builders, OEMs, and maintenance professionals to add additional signaling, interlocking, monitoring, and control functions to industrial automation systems without increasing panel complexity. The 3RH2921-1DA20 features a 2 Normally Open (2NO) contact configuration and is designed for convenient side mounting on compatible Siemens contactors and relays.
In modern industrial control systems, auxiliary contacts play a critical role in feedback monitoring, safety interlocking, status indication, sequential control, and automation processes. The Siemens 3RH2921-1DA20 Auxiliary Contact Block provides an efficient solution for extending control functionality while maintaining the reliability and performance expected from Siemens industrial products. By adding two additional normally open contacts, the device helps improve flexibility in motor control centers, process automation systems, machine control panels, and electrical distribution applications.
The 3RH2921-1DA20 is designed as a laterally mountable auxiliary switch block, allowing installation on either the left or right side of compatible Siemens contactors. This space-saving design eliminates the need for additional mounting hardware while enabling fast installation and simple integration into existing control systems. The snap-on construction significantly reduces installation time and helps maintain organized control panel layouts.
A key advantage of the Siemens 3RH2921-1DA20 is its 2NO contact configuration, which provides additional signaling and control options for industrial applications. The auxiliary contacts can be used for status indication, PLC inputs, control logic expansion, safety circuits, alarm systems, and interlocking functions. This versatility makes the accessory suitable for manufacturing facilities, process industries, infrastructure projects, water treatment plants, HVAC systems, and material handling operations.
The device is equipped with reliable screw terminal connections, ensuring secure wiring and dependable electrical performance in demanding industrial environments. Screw terminals remain a preferred choice for many panel builders and maintenance teams due to their ease of installation, strong mechanical retention, and long-term reliability. The robust connection design helps maintain stable electrical continuity even in environments exposed to vibration and frequent operation.
The Siemens SIRIUS 3RH2921-1DA20 is compatible with selected 3RT contactors and 3RH contactor relays, making it a valuable accessory for expanding existing Siemens motor control and automation systems. Designed according to Siemens' modular SIRIUS concept, the auxiliary contact block allows users to customize control functions while maintaining system consistency and reducing component inventory.
Built to Siemens' high industrial standards, the 3RH2921-1DA20 Auxiliary Contact Block delivers excellent durability and long service life. The unit is designed for continuous operation in industrial environments and supports reliable switching performance over millions of operating cycles. Its compact dimensions help maximize control panel space while ensuring easy accessibility during installation and maintenance procedures.
The compact design of the auxiliary block measures approximately 57.4 mm height, 10 mm width, and 66 mm depth, making it ideal for installations where panel space optimization is critical. Despite its small footprint, the accessory delivers robust performance and seamless integration into Siemens control systems.
The Siemens 3RH2921-1DA20 is widely used across industries requiring enhanced control functionality, including industrial automation, motor control systems, machine building, packaging equipment, process control systems, electrical distribution panels, and OEM machinery. Its proven Siemens engineering ensures dependable operation, reduced downtime, and enhanced control flexibility.
At SBsmart.in, we provide genuine Siemens industrial automation and control products trusted by engineers, contractors, panel builders, and industrial buyers worldwide. When you choose the Siemens 3RH2921-1DA20 Lateral Auxiliary Contact Block, you receive an authentic Siemens accessory designed for reliable performance, simple installation, and long-term operational efficiency.
Whether you are expanding an existing control panel, upgrading automation equipment, or designing a new motor control system, the Siemens 3RH2921-1DA20 offers a dependable and cost-effective solution for increasing auxiliary contact capacity while maintaining Siemens-quality performance and reliability.
| Specification | Details |
|---|---|
| Product Name | Lateral Auxiliary Contact Block |
| Manufacturer | Siemens |
| Series | SIRIUS 3RH29 |
| Model Number | 3RH2921-1DA20 |
| SKU | 3RH2921-1DA20 |
| Product Type | Auxiliary Switch Block |
| Mounting Position | Lateral (Side Mounted) |
| Contact Configuration | 2 Normally Open (2NO) |
| Number of Contacts | 2 |
| Contact Type | Auxiliary Contacts |
| Terminal Type | Screw Terminal |
| Mounting Method | Snap-On |
| Compatible Devices | Siemens 3RT Contactors & 3RH Relays |
| Width | 10 mm |
| Height | 57.4 mm |
| Depth | 66 mm |
| Operating Temperature | -25°C to +60°C |
| Storage Temperature | -55°C to +80°C |
| Mechanical Endurance | Up to 10 Million Operations |
| Standards | IEC 60947 Series |
| Application | Control Circuit Expansion & Signaling |
| Product Family | Siemens SIRIUS Accessories |
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