AC Motors
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Motors
Part 8 – Sizing Motor Feeder Protection and OCPD’s Devices
How to Determine the Size of Feeder Protection Supplying Several Motors? In the previous section, we discussed sizing feeder conductors for multiple motors. This section will explain the step-by-step process…
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Motors
Part 7 – Sizing Motor Branch Circuit Protection and OCPDs
How to Select OCPDs and Right Size Breaker / Fuse for Motor Overcurrent Protection? Sizing Branch Circuit Protection for Motors The sizing of overcurrent protection devices (OCPDs) for motor branch-circuit…
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Motors
Part 6 – Sizing Motor Feeder Conductors and Cables
How to Determine the Correct Wire Size for Feeder Supplying Multiple Motors? In previous sections on motor circuit calculations, we determined conductor sizing, overcurrent protection, and overload protection with solved…
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Motors
Part 5 – Sizing Motor Branch Circuit Conductors and Cables
How to Determine the Correct Wire Size for Motor Branch Circuit? Sizing Motor Branch Circuit Conductors Sizing the conductors for motor branch circuit is selected at 125% of the motor…
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Motors
Part 4 – Calculating Locked Rotor Current (LRC) for Motors
How to Determine the Value of Locked-Rotor Current (RLC) for Induction Motors? What is Locked-Rotor Current (RLC)? Locked-rotor current (LRA) is the maximum starting current drawn by an electric motor…
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Motors
Part 3 – Understanding NEMA Motor Nameplate Data and Marking
How to Read NEMA Motor Nameplates Data Printed on It for Motor Circuits? What is NEMA? NEMA (National Electrical Manufacturers Association) is a U.S.-based trade association that develops and publishes…
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Motors
Part 2 – NEC Requirements for Motor Circuits
General Requirements for the Design, Installation, and Protection of Motors, Motor Circuits, Controllers, and Disconnects – 2023 NEC Article 430 As discussed in part 1, motor circuits differ significantly from…
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Motors
Part 1 – Motor Load Circuits: NEC Terms and Terminologies
NEC Terms and Basic Terminologies Used in Motor Load Circuits Before designing an effective motor circuit that operates as expected based on analysis and calculations, it is important to understand…
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Motors
Why Do DC Motors Have Higher Starting Torque than AC Motors?
Why is the Starting Torque of a DC Motor Greater Than That of an AC Motor? DC (direct current) motors generally have higher starting torque compared to AC (alternating current)…
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Motors
Why is the Synchronous Motor Not Self Starting?
Why are Synchronous Motor and Synchronous Machines Not Self Starting? We know that a synchronous motor is not a self starting machine. This is because when the armature (stator) of…
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