Nema Starters

Nema sized contactors or 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:

Maximum Horsepower (hp)
NEMA SizeNEMA Continuous Amp Rating
(amps)
Full Voltage StartingPart Winding StartingWye Delta Starting
200V230V460V 575V200V230V460V 575V200V230V460V 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 1,000

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:

Maximum Horsepower (hp)
NEMA Size115 volts230 volts
00 1/3 1
0 1 2
1 2 3
2 3 7.5
3 7.5 15

Related Topics

  • Electrical - Electrical units, amps and electrical wiring, wire gauge and AWG, electrical formulas and motors

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