Description
DEIF
UNI-LINE
TYPE: RMP-121D
REVERSE POWER RELAY
MEAS VOLTAGE: 110VAC
MEAS POWER: 570W
100008948 10
MODULE: 63.3V
MODULE: 3A / SCALE: 0.99
SUPPLY: 24VDC
COUPLING: 1W3
600V CAT III.
The DEIF RMP-121D is a precision reverse power relay forming part of the DEIF Uni-Line modular protection relay series, designed for use within marine power control and generator management systems. Its primary function is to detect reverse power flow — a condition where a generator begins motoring rather than generating — and initiate a protective trip to prevent mechanical and electrical damage to the prime mover and switchgear. Forming a critical layer of protection in shipboard power distribution, this relay is an essential component within Marine Control System applications aboard commercial, offshore, and naval vessels where generator paralleling and load sharing are routine operations.
Key Features
✓ Reverse power detection relay with a measurement voltage of 110VAC and a measurement power threshold of 570W, operating on a 24VDC supply with 600V CAT III rating for robust shipboard electrical environments.
✓ Modular Uni-Line architecture with a module voltage of 63.3V and a current module rated 3A at a scale factor of 0.99, allowing accurate power measurement and relay calibration within the protection scheme.
✓ Coupling configuration 1W3 (single-wattmeter, three-wire) suited for three-phase power systems commonly found in marine generator panels and main switchboards.
✓ Designed for integration within DEIF Uni-Line compatible protection and control panels; exact panel and system compatibility should be confirmed against installation drawings and switchboard documentation.
✓ Suitable for DIN-rail or panel mounting within enclosed switchboard enclosures; replacement or retrofit installations should reference the original wiring diagram and module configuration to ensure correct scaling and trip settings.
Marine Applications
✓ Generator protection on main and emergency switchboards aboard cargo vessels, tankers, and bulk carriers where multiple generators operate in parallel.
✓ Power management systems on offshore support vessels, platform supply vessels, and drilling units requiring reliable reverse power detection during generator synchronisation and load transfer.
✓ Integration within DEIF-based power control systems on ferries, RoPax vessels, and passenger ships where continuous and reliable generator protection is operationally critical.
✓ Retrofit and upgrade applications on vessels replacing legacy reverse power protection relays within existing Uni-Line or compatible modular relay panels.
✓ Auxiliary generator protection on naval auxiliaries, dredgers, and specialist workboats where precise power flow monitoring supports safe and efficient electrical plant operation.
Why Marine Engineers Choose
The DEIF RMP-121D is valued for its modular design, accurate power measurement, and reliable reverse power trip functionality — qualities that make it a trusted component in shipboard generator protection schemes where the consequences of undetected reverse power can include prime mover damage, switchboard faults, and loss of vessel power.
Ideal For
Commercial cargo vessels, tankers, bulk carriers, offshore support and supply vessels, passenger ferries, naval auxiliaries, dredgers, and any seagoing vessel operating DEIF Uni-Line protection relay systems within its power generation and distribution plant.
Technical Support & Compliance
Technical support is available for remote troubleshooting, onboard fault diagnosis, testing and commissioning, relay calibration, and retrofit or upgrade integration — subject to confirmation of the specific installation context. For applications requiring system integration or replacement verification, buyers are advised to share nameplate photographs, the original part number, wiring diagrams, switchboard model and software version where applicable, vessel name, IMO number, and a clear description of the scope of work. Compatibility with specific panels, protection schemes, and vessel electrical systems is subject to confirmation based on the documentation provided.
