Phase Control Relay
All-in-One Fixed Parameter Protection
Complete three-phase monitoring with fixed parameters — ±15% over/under voltage, 8% asymmetry, and 5s delay — ready to install without any configuration. The simplest, most robust solution for standardized motor and equipment protection.
📋 Models & Ordering
| Model | System Type | Supply Voltage | Terminals | Protection Functions | Datasheet |
|---|---|---|---|---|---|
| FCP18-06A | 3-phase 3-wire (L-L) | 173–275V AC | L1 – L2 – L3 | Phase Loss + Seq. + OV/UV ±15% + Asym. 8% | 📄 Download PDF |
| FCP18-06B | 3-phase 4-wire (L-N) | 100–160V AC | L1 – L2 – L3 – N | Phase Loss + Seq. + OV/UV ±15% + Asym. 8% | 📄 Download PDF |
| FCP18-06C | 3-phase 3-wire (L-L) | 310–480V AC | L1 – L2 – L3 | Phase Loss + Seq. + OV/UV ±15% + Asym. 8% | 📄 Download PDF |
| FCP18-06D | 3-phase 4-wire (L-N) | 180–278V AC | L1 – L2 – L3 – N | Phase Loss + Seq. + OV/UV ±15% + Asym. 8% | 📄 Download PDF |
💡 Model selection guide: A/C for 3-wire (L-L), B/D for 4-wire (L-N). All parameters are fixed: Overvoltage +15%, Undervoltage -15%, Asymmetry 8%, Time Delay 5s. No user configuration needed — simply connect and the relay protects your equipment automatically.
⚙️ Technical Specifications
🔌 Input — Measuring (All Models)
| Supply Terminal (A/C) | L1 – L2 – L3 |
| Supply Terminal (B/D) | L1 – L2 – L3 – N |
| Monitoring Terminal | Same as supply terminal |
| Supply Voltage (A) | 173–275V AC L-L |
| Supply Voltage (B) | 100–160V AC L-N |
| Supply Voltage (C) | 310–480V AC L-L |
| Supply Voltage (D) | 180–278V AC L-N |
| Supply Frequency | 45–60Hz |
🛡️ Monitoring Function (All Fixed)
| Phase Failure | ✔ (Response < 200ms) |
| Phase Sequence | ✔ (Response < 500ms) |
| Overvoltage | +15% fixed |
| Undervoltage | -15% fixed |
| Asymmetry | 8% fixed |
| Time Delay | 5s fixed |
🔌 Output
| Contact | 1 × SPDT |
| Rated Current | 16A @ 250V AC |
| Mechanical Life | 1×10⁷ operations |
| Electrical Life | 1×10⁵ operations |
📐 Physical & Environmental
| Dimensions | 18 × 90 × 64 mm |
| Mounting | DIN rail EN 60715 |
| Protection Degree | IP40 (front) / IP10 (terminals) |
| Operating Temp. | -20°C ~ +55°C |
| Storage Temp. | -30°C ~ +70°C |
📜 Standards & Certifications
| Compliance | GB/T 14048.5, IEC 60947-5-1, EN 6812-1 |
| Contact Configuration | SPDT: 11(COM)-12(NC)-14(NO) |
| Pollution Degree | 2 |
| Max. Cable Size | AWG 13–20 / 0.4 N·m |
| Setting | None required — all factory-preset |
💡 Panel LED Indicators
| LED | Color | Status | Meaning |
|---|---|---|---|
| Un | Green | OFF | Supply voltage not applied |
| Un | Green | ON | Supply voltage applied |
| P | Red | ON | Phase normal (correct sequence, all phases present) |
| P | Red | Flashing | Phase sequence error |
| P | Red | OFF | Phase loss detected |
| R | Red | OFF | NC (11-12) contact closed |
| R | Red | ON | NO (11-14) contact closed |
📈 Function Diagram – Phase Loss & Sequence Protection
• The relay continuously monitors the three-phase supply connected to L1-L2-L3 (and N for 4-wire models).
• When all three phases are present and in correct sequence, the output relay R closes after the fixed 5-second delay. The P LED stays ON.
• If a phase loss is detected, the output relay R opens immediately (within 200ms). The P LED turns OFF.
• If a phase sequence error is detected, the output relay R opens immediately. The P LED flashes.
• When the fault clears, the relay automatically re-closes after the 5-second re-energization delay.
📈 Function Diagram – Overvoltage & Undervoltage Protection (±15%)
• The relay monitors voltage with fixed thresholds: +15% overvoltage and -15% undervoltage relative to the nominal input voltage.
• If voltage goes above +15% of nominal, the output relay R opens after the fixed 5-second delay. Recovery below the threshold automatically re-closes R.
• If voltage drops below -15% of nominal, the output relay R opens after the fixed 5-second delay. Recovery above the threshold automatically re-closes R.
• No configuration required — these thresholds provide balanced protection for standard industrial equipment.
📈 Function Diagram – Asymmetry (Phase Imbalance) Protection (8%)
• The relay calculates voltage asymmetry between phases: Asy = (Umax - Umin) / Uavr.
• When asymmetry exceeds the fixed 8% threshold, the output relay R opens after the fixed 5-second delay.
• If asymmetry drops back below 8%, the output relay automatically re-closes.
• The 8% threshold is ideal for general-purpose motor protection, preventing overheating while avoiding unnecessary trips from minor grid imbalances.
🎬 See it in Action
🔧 Wiring & Terminal Layout
Terminal Identification
3-phase 3-wire models (A/C): Connect L1, L2, L3 directly. No neutral connection required.
3-phase 4-wire models (B/D): Connect L1, L2, L3, and N. The wiring diagram shown is for 4-wire models. For 3-wire models, simply omit the N terminal.
Shown: 4-wire (L-N) wiring for B/D models. For A/C models, omit the N terminal.
🕹️ How It Works — Plug & Protect
- Apply Three-Phase Supply: Connect L1, L2, L3 (and N for B/D models) to the monitored supply. The green Un LED illuminates.
- Automatic Phase & Voltage Check: The relay verifies phase sequence and checks that voltage is within ±15% of nominal. After a 5-second delay, if all conditions are normal, the output relay R closes.
- Continuous Protection: The relay monitors for phase loss, sequence error, over/under voltage (±15%), and asymmetry (8%). Any fault causes the output to open after the 5-second delay (except phase loss/sequence, which trip immediately).
- Automatic Recovery: When the fault clears, the relay automatically re-closes after the fixed 5-second stabilization delay. No user intervention required.
🏭 Typical Applications
Pre-configured for general-purpose three-phase motor starters and contactors
Reliable plug-and-play protection for water, wastewater, and irrigation pumps
Protects compressors, fans, and chillers with zero configuration needed
Prevents reverse operation and motor damage from supply faults
Standardized protection across machine series — no field adjustments needed
Fixed protection for elevator, escalator, and ventilation three-phase supplies
🔗 Related Products
Explore other phase relays in the FCP18 series, or time relays in the FCT18 series:
❓ Frequently Asked Questions
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