Description
DEIF
TYPE: RMP-121D
REVERSE POWER RELAY
ORDER NO: 100131104.10
MEAS VOLTAGE: 440 VAC, <0.5 MA
UL: MAX. 450 VAC
MODULE: 240V
MEAS POWER: 2162 W
MODULE: 3A
SCALE: 1
SUPPLY VOLTAGE: 240 VAC
COUPLING: 1W3
RELAY OUTPUT: MAX. 250 VAC OR 24 VDC, 8A
ANALOG OUTPUTl: MAX. 10V
RELAY B: NORMAL DE ENERGISED
The DEIF RMP-121D is a dedicated reverse power relay designed to detect and respond to reverse active power flow within marine electrical distribution systems. As a core component within a ship’s Marine Control System, it provides essential generator and switchboard protection by monitoring power direction and triggering a relay output when reverse power conditions are detected. Preventing reverse power flow is critical to safe parallel generator operation and the protection of prime movers onboard commercial and industrial vessels. The RMP-121D operates on a 240 VAC supply voltage and is configured for single-phase measurement across a three-wire coupling (1W3), with a measurement voltage rating of 440 VAC.
Key Features
✓ Detects reverse active power flow with a measured voltage of 440 VAC (<0.5 mA) and a measured power reference of 2162 W, providing precise protection thresholds for generator management applications.
✓ Relay output rated at maximum 250 VAC or 24 VDC at 8A, with an analog output of up to 10V, enabling integration with a wide range of switchboard control and alarm systems — subject to configuration confirmation.
✓ Supply voltage of 240 VAC with a 240V module configuration and 3A module rating; coupling type 1W3 (single-wattmeter, three-wire) suits typical marine generator paralleling arrangements.
✓ Relay B operates in a normally de-energised state, consistent with fail-safe design principles commonly required in marine power protection schemes and switchboard safety standards.
✓ Compact relay module format suited for panel or DIN-rail installation within enclosed switchboard cubicles or generator control panels; precise mounting dimensions and environmental ratings should be confirmed against installation drawings.
Marine Applications
✓ Generator paralleling protection on main switchboards aboard cargo vessels, tankers, and offshore support vessels where reverse power could damage prime movers during load sharing.
✓ Shore power and generator changeover sequences on passenger ferries and RoPax vessels, where reverse power detection is required during synchronisation events.
✓ Integrated into DEIF power management and generator control systems aboard platform supply vessels, anchor handlers, and other DP-capable workboats.
✓ Auxiliary generator protection panels on bulk carriers, container ships, and general cargo vessels operating with multiple generating sets in parallel.
✓ Retrofit and replacement applications within existing DEIF-based control architectures where the original reverse power relay module requires like-for-like exchange.
Why Marine Engineers Choose
The DEIF RMP-121D is a well-established reverse power protection relay trusted in marine power management for its reliable detection capability, clear relay output behaviour, and compatibility with DEIF generator control ecosystems. Its defined electrical ratings and straightforward coupling configuration make it a practical choice for both OEM replacement and panel upgrade projects.
Ideal For
Cargo ships, tankers, offshore support vessels, platform supply vessels, passenger ferries, bulk carriers, container vessels, and any commercial or industrial vessel operating parallel generating sets with DEIF-based power management and control systems.
Technical Support & Compliance
Technical assistance is available to support remote troubleshooting, onboard diagnostics, relay testing and commissioning, repair assessment, retrofit integration, and system compatibility verification — all subject to confirmation based on the specific vessel configuration. To confirm suitability, buyers are encouraged to share nameplate photographs, the full order number (100131104.10), relevant panel or system drawings, the generator control system model and software version, vessel name, IMO number, and the intended scope of supply or installation. Compatibility with specific DEIF control panels or third-party switchboard systems is subject to confirmation against provided documentation.
