Application - They are used to protect engines of any power against effects of an interruption in the supply circuit, voltage drop (unbalance), or incorrect phase sequence. The PZA-2 and PZA-2 R relays additionally control the three-phase network downstream of the contactor, preventing damage to the motor in the event of suspension or burnout of the contactor's contacts. PZA-2 R additionally has adjustable activation threshold in the voltage range of 170 - 190V, and activation times from 0 - 6s.
Advantages:
→ response time: 3.5s (decay, asymmetry), instantaneous (incorrect phase sequence),
→ recovery time below: 1s,
→ operating threshold: 175V,
→ NO contact 8A (galvanically separated)
→ PZA-2, PZA-2R-phase loss, unbalance
→ PZAK phase loss, asymmetry, incorrect sequence.