NewTrend · three-phase monitoring relay
Product overview
NewTrend RV8-25 provides phase sequence, phase failure, asymmetry monitoring for three-phase control circuits. Set Un to the required three-wire or four-wire nominal voltage. The 18mm DIN-rail relay provides 2 SPDT contacts rated 8A (AC-1). Its exact protection settings are listed below; function codes have different combinations of fixed and adjustable thresholds.
Technical selection summary
| Model | RV8-25 |
|---|---|
| Functions | Phase sequence + phase failure + asymmetry |
| Voltage-system selection | 3P3W or 3P4W on the front selector |
| Three-wire nominal voltage | 380 / 400 / 415 / 440 / 480V, phase-to-phase |
| Four-wire nominal voltage | 220 / 230 / 240 / 254 / 277V, phase-to-neutral |
| 3P3W / 3P4W monitoring terminals | L1-L2-L3 / L1-L2-L3-N |
| Supply terminals | L1-L2 |
| Frequency / measurement | 45-65Hz; true RMS |
| 3P3W / 3P4W measuring ranges | 260-576V / 150-332V |
| Measurement error | Maximum 1% |
| Overvoltage / undervoltage | Not provided by this function code |
| Asymmetry protection | 5-20% |
| Trip delay | 0.1-30 seconds, adjustable |
| Phase-sequence protection | Provided |
| Power-up delay / reset time | 0.5s / 1s |
| Output contacts / rating | 2 SPDT / 8A (AC-1) |
| Switching voltage / minimum DC power | 250VAC / 24VDC; 500mW |
| Output / fault indication | Green LED / red LED |
| Mechanical / electrical life (AC-1) | 10,000,000 / 100,000 operations |
| Temperature coefficient | 0.05%/degree C at 20 degrees C |
| Operating / storage temperature | -20 to +55 / -35 to +75 degrees C |
| Mounting / operating position | DIN rail to EN/IEC 60715; any position |
| Protection | IP40 front panel; IP20 terminals |
| Overvoltage category / pollution degree | III / 2 |
| Maximum conductor size | Solid: 1 x 2.5mm2 or 2 x 1.5mm2; with sleeve: 1 x 2.5mm2 (AWG 12) |
| Tightening torque | 0.4Nm |
| Body dimensions | 90 x 18 x 64mm |
| Weight | 69-72g by version |
| Referenced standards | EN 60255-1; IEC 60947-5-1 |
| Phase-failure threshold | 70% of selected Un |
| Knob setting accuracy | 10% of scale value |
Operation
- Set Un to the required three-wire or four-wire nominal voltage.
- The green LED indicates relay-output state and the red LED indicates a fault. Loss of a supply phase at L1 or L2 can extinguish indication; do not interpret an unlit LED as proof that the circuit is safe.
Typical applications
- Phase supervision in motor contactor-control circuits
- Three-phase industrial control panels
View or download RV8-21 to RV8-26 catalogue (PDF)
Product reference images and drawings
RV8-21 to RV8-26 – selection and technical specifications
RV8-21 to RV8-26 – wiring, dimensions and operation
If Un is changed while operating, both LEDs flash and monitoring continues with the nominal voltage used at the last energization until the original setting is restored. Confirm the selected system and all settings before restarting. Installation and wiring must be performed by qualified electricians.
