Motor code letter = G (LRC = 5.6 kVA/HP) Starting kVA = 200 HP × 5.6 = 1120 kVA (full voltage)
Starting kVA = 1120 × 0.25 = 280 kVA (acceptable for 300 kVA transformer) nema mg1-32 amp- 33
A motor that starts well (MG1-32) but overheats (violates MG1-33) fails just as quickly as one that never starts at all. Disclaimer: This article is for informational purposes. Always refer to the official NEMA MG 1 standards document and consult a licensed professional engineer for specific applications. Motor code letter = G (LRC = 5
Use wye-delta starter: Starting kVA = 1120 × 0.33 = 370 kVA Use wye-delta starter: Starting kVA = 1120 × 0
The document is divided into "Parts" and then numbered "Sections." Sections 32 and 33 fall under (General Concerning Definite-Purpose Motors) and Part 31 (General Concerning Integral-horsepower Motors), respectively. Part 2: Deep Dive into NEMA MG1-32 What is NEMA MG1-32? NEMA MG1-32 is titled: "Determination of Motor Input kVA at Starting and During Acceleration for Reduced Voltage Starting."
In simpler terms, this section defines the standard methods for calculating the apparent power (kVA) that a motor draws from the line —specifically when using reduced-voltage starting methods such as autotransformers, part-winding, or wye-delta starters. Why is MG1-32 Critical? When an induction motor starts, it draws a high inrush current (typically 600% of full-load current) for a few cycles, followed by a starting current (typically 500–600% of full-load amps) until it reaches full speed. This current, multiplied by the voltage, gives the starting kVA .