Voltage and Frequency Limits of Electric Motors – IEC 60034-1
Electric motors rated for use on a fixed frequency power supply, combinations of voltage variation and frequency variation are classified as being either zone A or zone B, in accordance …
Low Voltage Circuit Breaker Selectivity Categories
I. What is Selectivity? Selection of the protection system of the electrical installation is fundamental to guarantee correct economical and functional service of the whole installation and to reduce the …
Power-line Surge voltages and Surge Currents – Causes and Effects
I. Causes Surge voltages and surge currents occurring in low-voltage ac power circuits can be caused by: Lightning surges. Lightning surges are the result of a direct flash to the …
Earth Fault Higher Than Three Phase Fault
In a power system, almost always three phase fault current is higher than the earth-fault current. However, earth fault current near the generator is higher than three phase fault. What …