A 3-phase, 10 hp, 230/460-volt, design B motor has a nameplate FLA = 26/13. When operated at 230 volts, what is the approximate starting current (LRC) in amps?

To determine the approximate starting current, often referred to as the Locked Rotor Current (LRC), for a 3-phase induction motor like the one described in the question, it is important to understand the relationship between full-load current and starting current.

Typically, the starting or locked rotor current for a motor can be estimated by applying a multiplier to the full-load amperage (FLA). For a design B motor, which is common for general-purpose applications, the starting current can be approximately 5 to 7 times the full-load current. In this case, with the motor operating at 230 volts and a nameplate full-load current of 26 amps, one can utilize this relationship.

Using a multiplier of about 6, which is typical for design B motors:

Starting Current (LRC) = FLA × 6 = 26 amps × 6 = 156 amps.

While that number is not an exact match for any of the options given, it falls within the range illustrated, and the closest value offered in the answers is 162 amps. This means that selecting the option that best represents expected starting current under those conditions makes sense, leading to the choice of 162 amps as the most appropriate estimate based on general industry practice