Siemens 6RY1803-1DA03 Replacement for SINAMICS SIMOVERT

Product Overview

Siemens 6RY1803-1DA03 Replacement for SINAMICS SIMOVERT: Smooth Transition from Legacy Drive Systems

The Siemens 6RY1803-1DA03 is a phase motor protection relay engineered for integration within the SINAMICS and SIMOVERT drive platform. As legacy SIMOVERT Masterdrives and earlier SINAMICS S120 cabinet configurations age out of active production support, facilities managers and automation engineers increasingly face the challenge of sourcing direct replacement components that preserve existing wiring infrastructure, control logic, and cabinet layout without triggering a full system redesign.

This relay module is designed to protect three-phase induction motors from phase loss, phase imbalance, and phase sequence faults — critical protection functions in high-availability production environments such as chemical processing, steel rolling mills, paper manufacturing, and municipal water treatment. When a legacy 6RY1803-1DA03 fails or reaches end-of-service life, the replacement must match the original’s terminal assignment, trip threshold calibration, and response time characteristics to avoid reprogramming the upstream SIMATIC S7-300 or S7-400 PLC that monitors the relay’s fault output.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful migration from a SIMOVERT Masterdrive cabinet to a modernized SINAMICS-based control architecture rarely involves a single component swap. In practice, the 6RY1803-1DA03 relay replacement is one node in a broader upgrade sequence. Engineers typically begin by auditing the existing SINAMICS S120 Control Unit CU320-2 or CU310-2 to confirm firmware compatibility with the new protection relay’s fault signal mapping. Where the original cabinet used a SIMOVERT Masterdrives Compact Plus inverter unit, the relay’s trip output feeds directly into the drive’s digital input terminal strip — a wiring path that remains unchanged in the replacement unit, eliminating the need to re-terminate field cables.

Power supply integrity is equally important during the transition. Many SIMOVERT cabinets rely on a Siemens SITOP PSU100S 24V DC power supply module to energize the relay coil and associated control logic. Verifying that the SITOP output voltage and current rating remain within the 6RY1803-1DA03’s coil specification prevents nuisance trips during commissioning. In parallel, the SINAMICS S120 Booksize Power Module PM340 feeding the motor circuit should be checked for firmware alignment, as mismatched firmware versions between the power module and the control unit can mask genuine phase fault events.

For facilities that operate mixed PROFIBUS DP and PROFINET networks, the relay’s hardwired fault output is typically wired to a Siemens ET 200SP distributed I/O module or a SIMATIC ET 200M IM153-2 interface module, which then reports the fault state to the SIMATIC S7-300 or S7-1500 PLC over the fieldbus. This architecture means the relay replacement does not require any changes to the PLC program’s fault-handling logic, provided the I/O address mapping in the hardware configuration (HW Config in STEP 7 or TIA Portal Device Configuration) is preserved.

Where cabinet space is constrained — a common scenario in retrofit projects where a SIMOVERT Compact Plus unit is being replaced by a SINAMICS G120 wall-mounted drive — the 6RY1803-1DA03’s compact DIN rail footprint allows it to be repositioned within the existing enclosure without requiring a new cable duct layout. Coupling this relay with a Siemens 3RT2 contactor and a 3RV2 motor starter protector provides a complete motor protection chain that meets IEC 60947-4-1 coordination requirements and satisfies most local electrical inspection standards.

For applications where the legacy system used an older 6SE70 SIMOVERT Masterdrives series drive with an integrated motor protection board, the 6RY1803-1DA03 serves as the external relay equivalent, restoring phase protection functionality while the main drive is upgraded to a current-generation SINAMICS S120 or G120 platform. Commissioning engineers should also verify the SINAMICS Braking Module and DC Link capacitor module ratings when performing a full cabinet retrofit, as these components interact with the motor protection relay’s trip response during regenerative braking events.

Retrofit Guidance FAQ

Q: Will the 6RY1803-1DA03 wiring terminals match my existing SIMOVERT cabinet harness?
A: Yes. The terminal layout is consistent with the SIMOVERT Masterdrives cabinet wiring standard. No re-termination of field cables is required for a direct swap. Confirm terminal designations against your cabinet’s as-built drawings before energizing.

Q: Do I need to modify my SIMATIC S7 PLC program after replacing this relay?
A: No program changes are required if the relay’s fault output is wired to the same I/O address as the original unit. The fault signal polarity (normally closed or normally open) should be verified against the original relay’s datasheet to ensure the PLC interprets the signal correctly.

Q: Is this relay compatible with PROFIBUS DP or PROFINET communication?
A: The 6RY1803-1DA03 uses a hardwired relay output rather than a fieldbus interface. It integrates into PROFIBUS DP or PROFINET architectures via a distributed I/O module (e.g., ET 200SP or ET 200M) that reads the relay’s digital output and transmits the fault state to the PLC over the network.

Q: What is the physical installation space requirement?
A: The relay is designed for DIN rail mounting and fits within standard SIMOVERT and SINAMICS cabinet enclosures. Verify the DIN rail section width and available vertical clearance in your cabinet before installation, particularly in Compact Plus retrofit scenarios where space is limited.

Q: Can this relay replace units from earlier 6RY18xx revision levels?
A: In most cases, yes. The 6RY1803-1DA03 is the current revision of the 6RY1803 series. Minor differences in trip threshold calibration between revisions should be verified against the motor’s nameplate current rating and the drive’s overload protection settings.

Q: What commissioning steps are recommended after installation?
A: After mechanical installation and wiring, perform a phase sequence test using a phase rotation meter before energizing the motor circuit. Verify the relay’s trip output by simulating a phase loss condition at the terminal strip. Confirm the SIMATIC PLC registers the fault correctly and that the drive’s fault log records the event as expected.

Warranty Assurance

Every Siemens 6RY1803-1DA03 unit shipped by TOPNLMS is covered by a 12-month warranty from the date of delivery. Prior to dispatch, each unit undergoes functional verification including coil continuity testing, contact resistance measurement, and trip response validation. Units that do not meet Siemens’ original specification tolerances are quarantined and not offered for sale.

In the event of a confirmed warranty claim, TOPNLMS provides a replacement unit or full refund within the warranty period. Our after-sales response team is reachable within one business day for technical queries related to installation compatibility, wiring verification, or commissioning support. We maintain bonded stock of critical SINAMICS and SIMOVERT spare parts in our Xiamen warehouse to support urgent replacement orders with same-day or next-day dispatch capability.

Procurement teams can request a formal quotation, packing list, and certificate of conformity for each order. We support T/T bank transfer, PayPal, and trade finance arrangements for qualified buyers. All export documentation is prepared in compliance with CN customs regulations and the destination country’s import requirements.