NPU, SW Version 1.8, ©ComAp, September 2003
NPU-1.8r2.PDF 3
2. Technical Specification
The NPU unit is designed for 3-phase mains protection. Operator can switch on/off available protections or
adjust limits and time delays for each protection.
Rated voltages are 100, 230, 400, 480 VAC selected by order - see order codes. Measuring voltage
frequency range is from 44 up to 68 Hz.
NPU power supply voltage can be in the range 90 ÷ 250 VAC or 16 ÷ 110 VDC selected by order - see
order codes.
NPU offers following protections:
• Over frequency protection
• Under frequency protection
• Over voltage protection
• Under voltage protection
• Phase sequence supervision
• Voltage asymmetry protection
• Vector shift supervision