Method for detecting the rotor position of a BLDC motor of a reciprocating piston compressor in a household appliance with at least two permanent magnetic pole pairs and controlled magnetic pole pairs electrically generated in windings with the method steps a. Controlled test run for detecting the rotor position; b. Assign the rotor position of a characteristic external load torque to an assigned controlled magnetic pole pair, wherein the BLDC motor is moved with a constant rotating voltage vector with at least two phases (47, 48, 49) for generating the controlled magnetic pole pairs in the windings, and that in method step a. a phase current value is measured step by step at the voltage vector, a calculated phase current curve is calculated from a plurality of measured phase current values and a deviation from measured phase current values is determined in each case from an assigned value of the calculated current curve, or the BLDC motor is moved with a constant rotating current vector with at least two phases (50, 51, 52) for generating the controlled magnetic pole pairs in the windings, and that in method step a. a duty cycle value at the current vector is stored step by step, a calculated duty cycle curve is calculated from a plurality of stored duty cycle values and a deviation of measured duty cycle values is determined in each case from an assigned value of the calculated duty cycle curve, wherein in method step b. the rotor position of the characteristic external load torque is assigned to the assigned controlled magnetic pole pair on the basis of a characteristic deviation of the detected values. a. Controlled test run for detecting the rotor position; b. Assign the rotor position of a characteristic external load torque to an assigned controlled magnetic pole pair, wherein the BLDC motor is moved with a constant rotating voltage vector with at least two phases (47, 48, 49) for generating the controlled magnetic pole pairs in the windings, and that in method step a. a phase current value is measured step by step at the voltage vector, a calculated phase current curve is calculated from a plurality of measured phase current values and a deviation from measured phase current values is determined in each case from an assigned value of the calculated current curve, or the BLDC motor is moved with a constant rotating current vector with at least two phases (50, 51, 52) for generating the controlled magnetic pole pairs in the windings, and that in method step a. a duty cycle value at the current vector is stored step by step, a calculated duty cycle curve is calculated from a plurality of stored duty cycle values and a deviation of measured duty cycle values is determined in each case from an assigned value of the calculated duty cycle curve, wherein in method step b. the rotor position of the characteristic external load torque is assigned to the assigned controlled magnetic pole pair on the basis of a characteristic deviation of the detected values. the BLDC motor is moved with a constant rotating current vector with at least two phases (50, 51, 52) for generating the controlled magnetic pole pairs in the windings, and that in method step a. a duty cycle value at the current vector is stored step by step, a calculated duty cycle curve is calculated from a plurality of stored duty cycle values and a deviation of measured duty cycle values is determined in each case from an assigned value of the calculated duty cycle curve, wherein in method step b. the rotor position of the characteristic external load torque is assigned to the assigned controlled magnetic pole pair on the basis of a characteristic deviation of the detected values.