Nema Starters
NEMA electrical motor starters refer to a standardized rating system for the electrical performance of the most common style of American-built motor starters. NEMA starters are rated by size: 00, 0, 1, 2, 3, 4, 5, 6 and 7.
Polyphase Motors
Maximum electrical motor horsepower for different NEMA starters for three phase motors can be found in the table below:
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| NEMA Size | NEMA Continuous Amp Rating (amps) | Full Voltage Starting | Part Winding Starting | Wye Delta Starting | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 200V | 230V | 460V 575V | 200V | 230V | 460V 575V | 200V | 230V | 460V 575V | ||
| 00 | 9 | 1 1/2 | 1 1/2 | 2 | ||||||
| 0 | 18 | 3 | 3 | 5 | ||||||
| 1 | 27 | 7.5 | 7.5 | 10 | 10 | 10 | 15 | 10 | 10 | 15 |
| 2 | 45 | 10 | 15 | 25 | 20 | 25 | 40 | 20 | 25 | 40 |
| 3 | 90 | 25 | 30 | 50 | 40 | 50 | 75 | 40 | 50 | 75 |
| 4 | 135 | 40 | 50 | 100 | 75 | 75 | 150 | 60 | 75 | 150 |
| 5 | 270 | 75 | 100 | 200 | 150 | 150 | 350 | 150 | 150 | 300 |
| 6 | 540 | 150 | 200 | 400 | 300 | 600 | 300 | 350 | 700 | |
| 7 | 810 | 300 | 600 | 450 | 900 | 500 | 500 | 1000 | ||
Ease of selection is a fundamental design advantage of a NEMA-style starter. To select a NEMA starter only horsepower and voltage are needed. NEMA starters have interchangeable heater elements and makes NEMA starters attractive in projects where the motor specification is not known until the start-up date.
Single Phase Motors
Maximum horsepower with full voltage starting and two pole contactors are indicated below:
| NEMA Size | 115 volts | 230 volts |
|---|---|---|
| 00 | 1/3 | 1 |
| 0 | 1 | 2 |
| 1 | 2 | 3 |
| 2 | 3 | 7.5 |
| 3 | 7.5 | 15 |
- More about NEMA
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