Electrical Power Engineering

Motor Duty Cycle Ratings: NEMA section: Duty Continue = Motor designed to working continuous without effect to temperature of winding and life time motor. Each motor that operated more than 3 hours belong to duty continue. Intermittent Duty = Motor designed to working in certain time then stop in certain time to cool, and then start again. Special = motor works in specific time. For instance, 5, 15, 60 minutes.

What is power factor - Power factor is defined as the ratio of real power to apparent power in the circuit. Power in the circuit are Apparent Power (VA), Real Power (Watt), and Reactive Power (VAR).

How To Read Motor Nameplate - Every motor nameplate must show basic data such as voltage, Full Load Ampere (F.L.A), and frequency. North America, Europe, Japan, Africa, has different standard. To know standard of motor is very important. It helps you from buying wrong motor. Yet, no each motor has specific data. Sometimes name plate did not show the diagram voltage, efficiency. Nevertheless, many motor always show voltage, full load ampere and frequency. NEMA: National Electrical Manufacture Association NEC: National Electrical Code JIS: Japanese Industrial Standard IEC: International Electrotechnical Commision