SPRECHER + Schuh, represented in Australia by NHP , has released the CET5 motor protection relay.
It can control, monitor and protect motors. By taking advantage of the facility to set alarm warning levels, downtime can be reduced or even avoided by allowing preventative maintenance or reduction of throughput. The relay uses a microprocessor-based thermal model to monitor motor performance during start, running and cooling (stopped) modes. This ensures that premature tripping is avoided and maximum protection provided at all times.
The motor thermal model is updated based on motor current which is fed into the CET5 via the CWE4 current converter module for processing using a single dedicated plug-in cable. The use of the CWE4 can negate the need for current transformers and can be directly fitted to CA6 contactors up to 630A.
The CET5 protects ac motors against various fault conditions by providing protective features to guard against thermal overload, earth fault, jam or stall conditions, underload, current asymmetry and phase loss, phase reversal and thermistor overtemperature. Several option cards allow more complete protection, control and monitoring of motor control systems.
Protection against motor overheating can lead to an extended motor life, resulting in long-term savings.