motor coil temperature detector d 1 and the discharge temperature detector d 6 in which drawing the constituents common to those of the refrigerating apparatus explained in the above are indicated with same reference numerals and descriptions thereof will be omitted as shown in fig1 in this refrigerating apparatus 10 g a step for determining whether the motor current is below the upper limit value yes or not no is added to the control flow chart thereof in addition to the flow chart shown in fig1 and in this refrigerating 10 g the determination as to whether the motor 22 is in the overload condition or not is trebly made based on three factors furthermore the order of three determination steps as to the motor coil temperature detector d 1 the discharge temperature detector d 6 and the current detector d 5 is optional rather than limited thereto 0065 fig1 shows a refrigerating apparatus 10 h incorporating a screw compressor 1 h additionally provided with the motor rotational speed detector d 7 in addition to the motor coil temperature detector d 1 the discharge temperature detector d 6 and the current detector d 5 in which drawing the constituents common to those of the refrigerating apparatus explained in the above are indicated with same reference numerals and descriptions thereof will be omitted as shown in fig1 in this refrigerating apparatus 10 h a step for determining whether the rotational speed of the motor is below the upper limit value yes or not no is added in the control flow chart in addition to the flow chart shown in fig1 and in this refrigerating apparatus 10 h the determination.