FCP18 Phase Relays for Motor & Equipment Protection

FCP18-01 is the basic model with only Phase Loss Protection and Phase Sequence Protection. No adjustable voltage monitoring.

FCP18-02 adds Overvoltage (+2%-20%) and Undervoltage (+2%-20%) protection with an adjustable Time Delay of 0.1-30s. This is the most popular model for general industrial applications.

If you only need phase monitoring without voltage level protection, FCP18-01 is sufficient. If you need to protect equipment from voltage fluctuations, choose FCP18-02.

Choose FCP18-03 when your application requires Phase Unbalance Protection. Unbalance occurs when the three phase voltages are not equal, which can overheat motors and cause premature failure.

FCP18-03 features: Full Voltage + Unbalance Protection, Over/Undervoltage 2%-20% adjustable, Time Delay 0.1-30s adjustable, and a fixed Unbalance threshold of 8%.

FCP18-03 is ideal for air conditioning compressors, HVAC systems, and any equipment sensitive to voltage imbalances. Use FCP18-02 if you don't need unbalance monitoring.

FCP18-03 has a fixed 8% unbalance threshold — pre-set at the factory. Simpler to use, no configuration needed.

FCP18-04 has an adjustable 5%-15% unbalance threshold via DIP switch, giving you flexibility to match specific equipment requirements. FCP18-04 also has a fixed 5s time delay.

Most standard motors can tolerate up to 5% unbalance. Sensitive equipment may require tighter thresholds (5-8%). FCP18-04 is best when you need custom settings; FCP18-03 for plug-and-play simplicity.

Asymmetric Protection (also called phase unbalance) detects when the voltage difference between the highest and lowest phases exceeds a set threshold, expressed as a percentage of the average voltage.

FCP18-05 monitors both positive and negative sequence components of asymmetric voltage, providing more comprehensive protection than simple unbalance detection.

Use FCP18-05 for critical applications requiring detailed asymmetric analysis, such as large motors in petrochemical, mining, or heavy industrial environments.

Fiicco FCP18 Phase Relays support two voltage classes:

• 380-440V: For three-phase industrial systems (most common)
• 220-240V: For lower-voltage three-phase systems or single-phase compatible applications

All models work on both 50Hz and 60Hz power systems. Operating temperature range: -20°C to +60°C. Storage temperature: -30°C to +70°C.

Time delay (or trip delay) is the preset waiting period before the relay trips when an abnormal condition is detected. This prevents nuisance tripping from brief transients such as motor startup voltage dips.

• FCP18-01: Time delay is fixed (internal setting)
• FCP18-02/03: Time delay adjustable 0.1-30s via DIP switch
• FCP18-04: Time delay fixed at 5s

For motors with high inrush current, use a longer delay (5-10s). For stable power grids, 0.1-2s is sufficient.

Phase loss (or single-phasing) occurs when one of the three phases drops out while the other two remain connected. This can happen due to utility faults, blown fuses, or cable damage.

When a motor loses one phase while running under load, it draws excessive current from the remaining two phases, causing:

• Severe overheating and motor burnout
• Loss of torque and mechanical stress
• Equipment damage and production downtime

All FCP18 models provide phase loss protection, disconnecting the load immediately when detected.

FCP18 Phase Relays are designed primarily for three-phase (3-phase) systems. They monitor the relationship between three phases (L1, L2, L3) for phase loss, sequence, and unbalance.

For single-phase voltage monitoring (over/under voltage protection), consider Fiicco FCR5-DU voltage relays instead.

If you need to monitor multiple single-phase circuits in a three-phase system, you would need one FCP18 for the three-phase aspects plus individual single-phase monitors for each circuit.