It is typically constructed of a laminated, cylindrical iron core with slots of cast-aluminum conductors. A 1.10 SF motor should not be loaded beyond its rated horsepower. Service factors will vary for different horsepower motors and for different speeds. Motor has low starting torque, low cost. Usually used in direct-drive fans and small blowers, and in small gearmotors.
Motor has moderate starting torque, high breakdown torque.
The amount by which a motor, operating under rated conditions, is hotter than its surrounding ambient temperature. A device, sensitive to current and heat, which protects the motor against overheating due to overload or failure to start. Basic types include automatic rest, manual reset and resistance temperature detectors. A protector, which is temperature-sensing only, that is mounted on the stator winding. Two leads from the device must be connected to control circuit, which initiates corrective action.