What minimum size starter is required for a 10 hp, 3-phase, 230/460-volt motor to be operated at 230 volts?

To determine the minimum size starter required for a 10 hp, 3-phase, 230/460-volt motor being operated at 230 volts, it's important to reference the National Electrical Code (NEC) guidelines, particularly around motor operation and starter selection. For a motor of this size and configuration, the minimum starter size is often determined based on the full-load current (FLC) of the motor.

A 10 hp motor at 230 volts typically has a full-load current rated around 29 amps. When selecting a motor starter, it is crucial to ensure that the starter can handle the starting current, which can be significantly higher than the running current. According to various NEC tables, starter sizes are generally indicated in terms of the number of poles or the ampacity that corresponds to the motor rating.

The correct starter size in this context is a size 2 starter, which is rated to handle currents appropriate for motors in this hp range without overloading. This ensures reliable operation while maintaining safety and compliance with electrical standards.

Choosing a starter that meets or exceeds the specified requirements is essential for preventing issues such as overheating and equipment failure, ensuring that the motor starts smoothly and operates effectively over its life span.