Abstract: A method for controlling the firing angle of a single-phase AC powered electric motor is provided which is triggered by at least one locking electronic switch, such as a triac (T1 and T4) located between the distribution voltage (UV) and at least one motor winding (A, B). According to said method, intervals are defined within which the triacs (T2 to T4) are to be fired according to the curve of the distribution voltage (UV) and the voltage (UEMK) induced in the respective winding in order to allow the motor to start as quickly and smoothly as possible and run quietly and at high efficiency.

Abstract: Disclosed is a method for controlling the firing angle of a signle-phase AC powered electric motor which is triggered by means of at least one locking electronic switch, especially a triac (T1 and T4) located between the distribution voltage (UV) and at least one motor winding (A, B). According to said method, intervals are defined within which the triacs (T2 to T4) are to be fired according to the curve of the distribution voltage (UV) and the voltage (UEMK) induced in the respective winding in order to allow the motor to start as quickly and smoothly as possible and run quietly and at high efficiency.

Abstract: The invention concerns a method for speed control of a compressor, particularly a refrigeration compressor, and a control arrangement using this method. The speed control is effected in that a control arrangement varies the speed of an electric motor in dependence of simple ON/OFF signals from a thermostat placed in the surroundings to be cooled. The method according to the invention is characterized in that the starting speed of the compressor in a following ON period is reduced in relation to the final speed in the previous ON period. A continuous reduction of the starting speed of each ON period results in a self-regulating control giving long compressor operation times and an averagely low speed resulting in energy savings. A control arrangement using this method is also described.