If a tech reads 5 FLA on the data plate, approximately what should the LRA be?

The correct answer is based on the relationship between Full Load Amperage (FLA) and Locked Rotor Amperage (LRA) in electrical systems. FLA is the current a motor draws when operating at its rated load under normal conditions, while LRA represents the amount of current the motor draws when it is starting up and the rotor is initially locked, typically leading to a much higher draw due to inertia.

For motors, LRA can be significantly higher than FLA, often ranging from 2 to 8 times the FLA, depending on the motor design and application. In this specific question, given an FLA of 5 amps, a reasonable calculation for LRA would place it within the range of about 10 to 40 amps. However, the most common and acceptable practice is to use a multiplier of around 3 to 5 times the FLA for estimation purposes in a typical HVAC context.

Therefore, with an FLA of 5 amps, estimating LRA as 3 to 5 times this value yields a range of approximately 15 to 25 amps, which aligns with the answer provided. Understanding this estimation is key in servicing and troubleshooting HVAC systems effectively.