SPR
Protection against network phase loss
Protection against contactor's imperfect contact
Protection against network undervoltage
Protection against phase reversal
Recognition of phase loss on the side of high-voltage network ® Fixed OFF delay time (0.5 second) in case of fault
Protection against network voltage asymmetry of 5 to 15%
Adjustable ON delay time from 0.5 to 30 seconds
Principles of Operation
The device IS designed fo protect threePohase motor against network inordinate undervoltage. phase reversal, phase loss and asymmetry in voltage of three phases. In many cases. the reason of alectromotor failures (damage) is imperfect connection of contactors’ contacts. Such a fault is not recognizable in ordinary systems while this device provides such a capabiity. Contactor output or motor points have to be connected to terminals U.. and W_ So. disconnection command wil be given when motor phase is last by which it avoids two-phase motor wordng. After connection of main three phases and null to tenminals R.S.7 and MP respectively. if network three phases are symmetric. voltage is in standard range and phase sequence is comect, relay acts after delay fime adjusted by DELAY potentiometer handle (contact 15 to 18 is mode) and OLT signal gets ON. Affer connection of power contactor provided that Output three phases of contactor are connected to terminals U. Vv. Wand all three phases are connected, system continues its nommal operation. But in the case of two-phase contactor output. network Phose Failure or asymmetry among network phases (when exceeding the adjustable limit by ASY.V potentiometer handle) out- put de-enengizes ight away and asymmetry signal (ASYV) gets ON. In the case of excessive network under voltage (around 25%) also output disconnects and VOLT signal gets ON. In the case of phase reversal. phase sequence signal (SEQ).) gets ON. After fault comection. device fimeracts then atthe end of time adjusted by DELAY potentiometer handle. output energizes.
Important Attention: This device must certainly be used with start and stop circuit.
Display Signals
OUT: Output contact connection display
SEQU. : Incomect phase sequence display a
VOLT. : Network undervoltage display
ASY.V : Phases’ voltage asymmetry display
Attention: Notice that Three-Phase-Monitor relay does not directly connect or dis- connect three phases but commands the contactor to do that.
Technical Specifications
Supply Voltage: 3-phase 4-wire 380 V + 10% @ Network Frequency: 50+5 Hz
Internal Loss: About 3.5 Watts
Voliage Asymmetry Adjustment: 5 to 15 % adjustable by ASY.V potentiometer handle
OFF Delay: 0.5 seconds
ON Delay: 0.5 to 30 seconds- adjustable by DELAY potentiometer handle
Output relay: Single-C/O contact
Contact Current: 6 A. 220 VAC -6 A. 28 VDC
