Product Description

🛍️ Siemens 3RV2921-1M Signaling Switch – For 3RV2 Circuit Breakers (Screw Terminals)

The Siemens 3RV2921-1M is a lateral, plug-in signaling switch designed for SIRIUS 3RV2 Motor Starter Protectors / Circuit Breakers (Frame Sizes S00, S0, S2, and S3). Installed on the left side of the circuit breaker, it provides separate, clear status signaling for tripped events and short-circuit faults.

Unlike standard auxiliary switches that simply reflect contact position, this switch differentiates between a standard manual/overload trip and a short-circuit fault, enabling faster diagnostics and targeted maintenance in industrial control panels.

Key Features & Technical Details

• Dual Signal Differentiation: Features 2 separate contact sets (1 NO + 1 NC for general trip, and 1 NO + 1 NC for short-circuit alarm).

• Universal 3RV2 Fit: Compatible across all 3RV2 circuit breaker sizes: S00, S0, S2, and S3.

• Reliable Screw Terminals: Uses heavy-duty screw-type terminals for secure wire connections up to $2.5\text{ mm}^2$.

• Side-Mount Modular Design: Snaps directly onto the left side of the breaker (18 mm width) without requiring tools or DIN rail modifications.

• Visual Fault Reset: Includes a manual reset lever/indicator on the front face to clear short-circuit alarm signaling after fault rectification.

• Finger-Safe IP20 Protection: Built with touch-proof housing to protect technicians during panel maintenance.

Ideal Applications

• PLC & Automation Alarm Diagnostics (differentiating overload vs. short-circuit trips)

• Motor Control Centers (MCCs) & Industrial Distribution Cabinets

• Emergency Stop & Safety Interlock Feedback Circuits

• OEM Machine Building with Remote Status Monitoring

❓ Frequently Asked Questions (FAQs)

Q1: How does the 3RV2921-1M signaling switch differ from a standard 3RV2901 auxiliary switch?

A: A standard auxiliary switch only signals whether the main breaker contacts are open or closed. The 3RV2921-1M signaling switch differentiates between trip reasons—it provides dedicated contacts to tell your PLC or control panel whether the breaker tripped due to an overload/manual switch off or a short-circuit fault.

Q2: Can I mount both a signaling switch and a standard auxiliary switch on the same 3RV2 breaker?

A: Yes. The 3RV2921-1M mounts on the left side of the breaker, leaving room for front-transverse auxiliary contacts (like 3RV2901-1E) or right-side accessories (like shunt trips or undervoltage releases).

Q3: Is there a spring-loaded terminal version of this signaling switch available?

A: Yes, if you require spring-type (cage clamp) terminals instead of screw terminals, the equivalent Siemens model is 3RV2921-2M.

🔗 Compatible Accessories & Cross-Selling Products

• Siemens SIRIUS 3RV2 Motor Starter Protectors: Compatible with 3RV20 (motor protection), 3RV21, and 3RV24 breakers across Sizes S00 to S3.

• Siemens 3RV2901-1E Transverse Auxiliary Contacts: Front-mounting auxiliary contact blocks (1 NO + 1 NC).

• Siemens 3RV2902 Series Shunt Releases / Undervoltage Releases: Right-side mountable accessories for remote automated trip control.