Siemens 3RT2026-1AG20 Replacement Solution for SIRIUS 3RT

Product Overview

Siemens 3RT2026-1AG20 Replacement Solution for SIRIUS 3RT: Smooth Transition & Legacy System Compatibility

The Siemens 3RT2026-1AG20 is a 25 A, 110 V AC coil, 3-pole AC power contactor from the SIRIUS 3RT series — one of the most widely deployed motor-switching devices in industrial control panels worldwide. Whether you are replacing a failed unit, upgrading an aging MCC (Motor Control Center), or migrating a legacy Siemens S5 or S7-300 control system to a modern S7-1500 architecture, the 3RT2026-1AG20 delivers a direct, drop-in upgrade path with minimal rewiring and zero program changes required at the PLC level.

Industrial facilities running older SIRIUS 3RT1 contactors — such as the 3RT1026-1AG20 predecessor — will find the 3RT2026-1AG20 dimensionally identical, with the same 45 mm width footprint, identical screw-terminal pitch, and the same DIN rail mounting profile. This means existing control cabinet layouts, cable duct routing, and terminal block assignments remain unchanged, dramatically reducing retrofit labor time and the risk of wiring errors during a live-system changeover.

For plants operating Siemens SIMATIC S7-300 or S7-400 PLCs with digital output modules such as the SM 322 DO 16×DC 24V or relay output cards driving contactor coils, the 3RT2026-1AG20’s 110 V AC coil is fully compatible with standard control transformer secondary circuits. No intermediate relay or voltage converter is needed, preserving the original control circuit topology and simplifying IEC 60204-1 compliance documentation during the upgrade audit.

When migrating to a SIMATIC S7-1500 platform with ET 200SP distributed I/O, engineers often pair the 3RT2026-1AG20 with a 3RH2122 auxiliary contact block to feed digital input status signals back to the CPU via PROFINET. The contactor’s front-mount auxiliary contact interface is unchanged from the 3RT1 generation, so existing 3RH2 auxiliary blocks clip on without modification — a critical advantage when retrofitting dozens of motor starters across a large process plant.

Power circuit connections use standard M4 screw terminals rated for up to 35 mm² conductors, compatible with existing cable lugs and ferrules. The 3RT2026-1AG20 is rated for AC-3 duty at 11 kW / 400 V, making it suitable for direct-on-line (DOL) starting of standard induction motors in pump, fan, conveyor, and compressor applications — the most common retrofit scenarios encountered in water treatment, food processing, and manufacturing automation.

For applications where the legacy system used a 3RT1026-1AG20 with a 3RU2126 overload relay, the same overload relay mounts directly onto the 3RT2026-1AG20 without an adapter. The combined contactor-overload assembly fits the same panel cutout and uses the same group installation busbar system, preserving the original 3RA2 or 3RA5 combination starter assembly if applicable.

Communication-level integration is straightforward: if the motor starter is monitored via a 3UF7 SIMOCODE pro motor management relay connected to PROFIBUS DP or PROFINET, the 3RT2026-1AG20 interfaces identically to its predecessor. No GSD file changes, no hardware configuration updates in TIA Portal, and no changes to the SIMOCODE parameter set are required — the motor management system sees the same contactor feedback signals it always has.

For control cabinets using SITOP PSU100S or SITOP PSU200M 24 V DC power supplies alongside 110 V AC control circuits, the 3RT2026-1AG20 coil draws approximately 8 VA at pickup and 5 VA sealed, well within the capacity of standard control transformers. This low coil burden is particularly valuable in dense panel designs where multiple contactors share a single transformer secondary winding.

Facilities managing spare-parts inventory for Siemens SIRIUS product lines will find the 3RT2026-1AG20 a strategic stocking item: it covers a broad range of 7.5–11 kW motor loads, replaces the discontinued 3RT1026-1AG20 on a 1:1 basis, and is cross-compatible with the full range of 3RT2 series accessories including surge suppressors, mechanical interlocks, and front-mount timer blocks. Consolidating around this single SKU can reduce spare-parts inventory complexity across multiple production lines.

Compatibility Comparison Table

Seamless Upgrade Solutions

A complete motor starter retrofit around the 3RT2026-1AG20 typically involves several complementary SIRIUS components. The 3RU2126-4AB0 thermal overload relay mounts directly to the contactor base and provides motor protection for 17–22 A loads without any additional mounting hardware. For applications requiring electronic motor protection with PROFIBUS or PROFINET connectivity, the SIMOCODE pro V PN (3UF7010-1AB00-0) replaces the conventional overload relay and delivers full motor management, diagnostics, and remote parameter access from TIA Portal.

Surge suppression is handled by the 3RT2926-1EA1 RC element, which clips directly onto the 3RT2026-1AG20 coil terminals to suppress inductive switching transients — essential in panels where sensitive ET 200SP I/O modules or SITOP power supplies share the same cabinet. Mechanical interlocking between two 3RT2026-1AG20 contactors for reversing-starter applications is achieved with the 3RA1921-1BA00 mechanical interlock kit, which requires no tools and no modification to either contactor.

For distributed control architectures, the 3RT2026-1AG20 integrates cleanly into SIMATIC ET 200pro motor starter assemblies or standalone panels wired to S7-1500 CM 1542-5 PROFIBUS DP communication modules. Existing 3RA2 combination starters using the 3RT1026-1AG20 can be upgraded by swapping only the contactor body, retaining the 3RV2 circuit breaker and busbar system.

Retrofit Guidance FAQ

Q: Do I need to re-terminate any wires when replacing a 3RT1026-1AG20 with the 3RT2026-1AG20?
A: No. The power terminal pitch, screw size (M4), and conductor capacity (up to 35 mm²) are identical. Control circuit terminals for the 110 V AC coil (A1/A2) are in the same position. No re-termination is required.

Q: Will my existing PLC program need modification?
A: No. The 3RT2026-1AG20 presents the same electrical interface to the control system. Output coil drive signals and auxiliary contact feedback signals are unchanged. No TIA Portal or STEP 7 project modifications are needed.

Q: Is the 3RT2026-1AG20 compatible with PROFIBUS DP or PROFINET systems?
A: Yes, when used with a SIMOCODE pro motor management relay (3UF7 series) or via standard digital I/O modules. The contactor itself is a passive switching device; communication is handled at the I/O or motor management layer, which remains unchanged.

Q: Can this contactor fit in the same panel space as the 3RT1026-1AG20?
A: Yes. The 3RT2026-1AG20 has the same 45 mm width and identical DIN rail footprint. No panel modifications, busbar changes, or cable duct adjustments are required.

Q: What overload relay is compatible?
A: The 3RU2126 series thermal overload relays mount directly without adapters. For electronic protection, the SIMOCODE pro V series is recommended.

Q: How do I verify the replacement is correct before installation?
A: Cross-reference the original nameplate data (coil voltage, rated current, frame size) against the 3RT2026-1AG20 datasheet. All units shipped by TOPNLMS are tested and include a factory test report.

Warranty Assurance

Every Siemens 3RT2026-1AG20 supplied by TOPNLMS is covered by a 12-month warranty from the date of shipment. Prior to dispatch, each unit undergoes coil continuity verification, contact resistance measurement, and mechanical operation testing. Units are shipped in original or equivalent protective packaging with full traceability documentation.

In the event of a confirmed defect within the warranty period, TOPNLMS provides a replacement unit or full refund — your choice. Our technical team responds to warranty claims within 24 business hours. We maintain buffer stock of the 3RT2026-1AG20 to support emergency replacement orders with same-day or next-day dispatch from our Xiamen warehouse.

For procurement teams managing MRO (Maintenance, Repair & Operations) budgets, TOPNLMS issues formal quotations, packing lists, commercial invoices, and certificates of origin to support customs clearance and internal purchasing workflows. Volume pricing is available for orders of 5 units or more.