Nema Starters

Overview

Engineering reference data for Nema Starters in miscellaneous.

Key Formulas

Unit Conversion

$y = x \cdot k$

Multiply by conversion factor.

Linear Interpolation

$y = y_1 + \frac{(x - x_1)(y_2 - y_1)}{x_2 - x_1}$

Estimate between two known points.

Percentage

$p = \frac{\text{part}}{\text{whole}} \times 100\%$

Part as fraction of whole.

Variables

Symbol	Description	Unit
$x$	Input value	—
$y$	Output value	—
$k$	Conversion factor	—

Polyphase Motor Starters

The table below shows the maximum motor horsepower ratings for three-phase (polyphase) motors based on NEMA starter size, supply voltage, and starting method.

Single-Phase Motor Starters

The table below lists the maximum motor horsepower ratings for single-phase motors using full voltage starting with two-pole contactors.

Starter Selection Criteria

Selecting a NEMA starter is straightforward and requires only two motor specifications:

1. Motor Horsepower (hp)
2. Motor Voltage (V)

A key practical advantage of NEMA starters is the use of interchangeable heater elements. This feature makes them particularly suitable for projects where the final motor specifications may not be confirmed until the installation or startup phase.

Interactive Charts

References

• Original Source