Phase Control Relay
Phase Loss, Sequence & Adjustable Asymmetry
Focused three-phase monitoring with adjustable asymmetry (5%–15%) and configurable time delay (0.1–30s) — perfect for applications where over/under voltage protection is not required but precise imbalance control is critical.
📋 Models & Ordering
| Model | System Type | Supply Voltage | Terminals | Protection Functions | Datasheet |
|---|---|---|---|---|---|
| FCP18-05A | 3-phase 3-wire (L-L) | 173–275V AC | L1 – L2 – L3 | Phase Loss + Seq. + Asym. (5-15%) | 📄 Download PDF |
| FCP18-05B | 3-phase 4-wire (L-N) | 100–160V AC | L1 – L2 – L3 – N | Phase Loss + Seq. + Asym. (5-15%) | 📄 Download PDF |
| FCP18-05C | 3-phase 3-wire (L-L) | 310–480V AC | L1 – L2 – L3 | Phase Loss + Seq. + Asym. (5-15%) | 📄 Download PDF |
| FCP18-05D | 3-phase 4-wire (L-N) | 180–278V AC | L1 – L2 – L3 – N | Phase Loss + Seq. + Asym. (5-15%) | 📄 Download PDF |
💡 Model selection guide: A/C for 3-wire (L-L), B/D for 4-wire (L-N). FCP18-05 provides Phase Loss, Phase Sequence, adjustable Asymmetry (5%–15%), and configurable Time Delay (0.1–30s). No over/under voltage protection.
⚙️ 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
| Phase Failure | ✔ (Response < 200ms) |
| Phase Sequence | ✔ (Response < 500ms) |
| Overvoltage | — |
| Undervoltage | — |
| Asymmetry | 5%–15% adjustable |
| Time Delay | 0.1–30s adjustable |
🔌 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 Deviation | 0% – Digital Setting |
💡 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 set time 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 set time delay.
📈 Function Diagram – Asymmetry (Phase Imbalance) Protection
• The relay calculates the voltage asymmetry between the three phases: Asy = (Umax - Umin) / Uavr.
• When asymmetry exceeds the user-set threshold (5%–15%), the output relay R opens after the set time delay T (0.1–30s).
• If asymmetry drops back below the threshold, the output relay automatically re-closes.
• Adjustable asymmetry protection is essential for preventing motor overheating caused by unbalanced supply voltages.
🎬 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.
🛠️ Parameter Setting Guide
- Enter Parameter Setting Mode: Press and hold the button until the LED starts flashing. This indicates you have entered the configuration mode.
- Set Rated Voltage (Un): Use the button to select the correct input voltage for your three-phase system. The available options are marked on the front panel scale.
- Set Asymmetry (Asy) Threshold: Choose the asymmetry trip point from 5% to 15%. This determines the maximum allowable voltage imbalance before the relay opens the output.
- Set Time Delay (Tt): Select the desired time delay from 0.1 to 30 seconds. This delay applies to initial start-up as well as to asymmetry and phase fault recovery.
- Confirm and Store: After all parameters are adjusted, press and hold the button until the LED stops flashing. The settings are stored and take effect immediately.
🏭 Typical Applications
Prevents overheating from phase imbalance in critical three-phase motors
Safeguards submersible and surface pumps from phase loss and imbalance
Ensures correct phase sequence and voltage balance for compressors
Prevents reverse operation and imbalance-related motor failures
Reliable three-phase monitoring for PLC-controlled production cells
Protects lathes, mills, and grinding machines from phase faults
🔗 Related Products
Explore other phase relays in the FCP18 series, or time relays in the FCT18 series:
❓ Frequently Asked Questions
📞 Need a Quote or Technical Support?
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