Abstract: A method of detecting phase loss of a three-phase AC power source includes steps of: acquiring any two line voltages of the AC power source with a first cycle period, acquiring a first digital signal and a second digital signal, performing an exclusive OR operation between the first digital signal and the second digital signal to generate a level signal, accumulating a high-level time count value, or accumulating a low-level time count value, resetting the low-level time count value when the high-level time count value is accumulated, or resetting the high-level time count value when the low-level time count value is accumulated, and determining that the AC power source occurs a phase-loss abnormality when the high-level time count value is greater than or equal to ? of the first cycle period or the low-level time count value is greater than or equal to ? of the first cycle period.

Abstract: A method of detecting phase loss of a three-phase AC power source includes steps of: acquiring any two line voltages of the AC power source with a first cycle period, acquiring a first digital signal and a second digital signal, performing an exclusive OR operation between the first digital signal and the second digital signal to generate a level signal, accumulating a high-level time count value, or accumulating a low-level time count value, resetting the low-level time count value when the high-level time count value is accumulated, or resetting the high-level time count value when the low-level time count value is accumulated, and determining that the AC power source occurs a phase-loss abnormality when the high-level time count value is greater than or equal to ? of the first cycle period or the low-level time count value is greater than or equal to ? of the first cycle period.

Abstract: A centrifugal concrete mixer includes a base frame, a mixing drum provided on the base frame, a transmission means and two stirring pieces. The transmission means has a power device driving a transmission shaft to rotate at a speed of 60 rpm to 600 rpm. One end of the transmission shaft penetrates into the mixing drum. A waterproof unit is provided between the transmission shaft and the mixing drum. The stirring pieces are assembled on the transmission shaft in the mixing drum. The stirring piece is formed into a plate. An outer surface of each stirring piece relative to its rotating direction is formed into an inclined surface. The outer end of each stirring piece is provided with an auxiliary stirring portion to face the inner surface of the mixing drum. The rotation of the stirring piece generates a centrifugal force to stir the concrete containing gravels.

Abstract: An improved structure of a cement mixing apparatus comprising a base frame, two supporting frames, a panel, a mixing cylinder and a transmission mechanism, characterized in that the base seat has a substantial square shaped structure having a plurality of mounting holes for screws; the supporting frame is a H-shaped structure with a plurality of mounting holes for screws to mount a reinforcing plate at the top end of the supporting frame to the base frame, the two supporting frames are mounted together with the reinforcing plate as a unit such that the base flames and two supporting frames are formed into a framework structure.