RELAY phase switch (Novatek PEF-301)

Universal automatic electronic phase selector designed to supply a single-phase load from a three-phase four-wire electrical network by automatically selecting the healthiest phase.

• evice type: automatic phase selector relay​
• nominal output voltage: 230 / 240 VAC
• supply network: 3-phase + neutral (3 × 380 / 400 VAC + N)
• mains frequency: 45–65 Hz
• phase monitoring: undervoltage, overvoltage, phase loss
• undervoltage threshold (Umin): adjustable 160–210 V
• overvoltage threshold (Umax): adjustable 230–280 V
• reset delay (Ton): adjustable 1–600 s
• return delay to priority phase (Tr): adjustable 5–200 s or excluded
• maximum switched current: 16 A
• maximum direct load power: 3.6 kW
• switching delay to reserve phase: ≤ 0.2 s
• protection class: Class II
• overvoltage category: II
• standards compliance: EN 60947-1, EN 60947-6-2, EN 55011, EN 61000-4-2
• dimensions: 70 × 90 × 65 mm
• weight: ≤ 0.20 kg

Per piece.

Installation: DIN-rail mounting, 35 mm
Wiring : 0.5–2 mm² conductors
Terminal tightening torque: 0.4 N·m
Load connection:

• direct connection for loads up to 16 A
• control of external magnetic contactors for loads above 16 A
• Protection requirement: must be installed upstream of a circuit breaker (≤ 16 A, curve B)

Primary function:

• ensures uninterrupted single-phase power supply by automatically switching the load to the phase with acceptable voltage

Operating principle:

• continuously monitors voltage presence and level on all three phases
• prioritizes phase L1 when voltage is within set limits
• switches to reserve phases if priority phase voltage is outside thresholds
• disconnects the load if all phases are outside acceptable limits
• restores supply automatically when voltage conditions return to normal

Typical applications:

• critical single-phase loads in three-phase installations
• pumps, compressors, refrigeration units
• control panels and essential auxiliary equipment