Table of contents 1. Direct Current2. Ohm's Law3. Alternative Current4. Effective Value5. Phase Difference6. Impedance7. Ohm's Law for AC8. Power9. Three-Phase Direct Current Analogy between the potential difference or the voltage and difference of water level of which static pressure results can be made. The pressure will enable a water flow. In the same way, the voltage will enable a flow of electrons called current. If the liquid is more viscous than water, it will be harder for it to flow. Morever, its circulation will as more difficult as pipes’ cross sectional area is low. The circuit will have a certain resistance to the flow. The same phenomenon occurs in electricity: an electrical resistor opposes the flow of current. When the current circulates only in
RME Review
3-Phase Motor Circuit Breaker Sizing – RME Review
How to properly size a motor circuit breaker? This article will tackle about the sizing of Inverse Time Circuit Breaker with regards to National Electrical Code (NEC). I have learned this not just in school, but also in review center for our national board exam. It's one of the essential topics you should know for future use especially in the design field. What is Circuit Breaker? Circuit Breaker is an over current protective device that can manually switch on/off and automatically trip when a short circuit fault occurs. Why do we need to size a circuit breaker? Circuit Breaker rating is sized according to its load/s. Thus, undersized circuit can always give false alarm to operation. While oversized can lead to equipment breakdown or
Overload Relay Sizing – part of RME review
In this article, I will explain to you how motor overload relay is sized according to National Electrical Code (NEC). I will be sharing with you what I have learned from college and review center when I took registered master electrician. What is an Overload Relay? Overload Relay is normally used for motor control as a protective device against overloading. It can be an electronic type or the conventional type that uses a bimetallic strip that will react to the amount of line current passing. It's wired in series with the power circuit for current sensing and has usually two contacts for signalling and command. Why do we need to properly size an Overload Relay? Overload relay must be properly sized