Split-phase NEMA frame general purpose AC motors have a main winding and an auxiliary winding for use in low-to-medium-torque applications such as for blowers, fans, and small conveyors. Motors are single-phase and have a lower starting torque and are less energy efficient compared to capacitor-start/capacitor-run, and three-phase motors. They have a less powerful, smooth, and softer startup for use in HVAC equipment that must gradually come up to speed. Models have NEMA frame construction with standard dimensions that allow drop-in replacement of motors from multiple suppliers with no modifications required to existing installations. Motors usually have no protrusions (such as capacitor covers) from the motor shell except where a conduit box is used to house the electrical connections between the external power cables and the internal electrical wiring of the motor. The frame size for these motors is shown on the motor nameplate under “Frame” or “FR”.