For screw compressors, modulation is achieved by the sliding valve mechanism. The inverter technology can be applied to rotary compressor too, to achieve variable capacity.

Inverter technology works on the principle of variable compressor motor speed – an electrical signal is given to the compressor motor to make it spin faster or slower, depending on the room load. If the room load is high, the compressor spins at a faster rpm and delivers higher capacity and conversely, if the room load is low, the compressor spins at a lower rpm to deliver lower output.

Digital Scroll technology operates on the principle of loading and unloading of scrolls. The motor runs at a constant speed but the scrolls are engaged and disengaged periodically to get durations of “full capacity” and “no capacity”. Time averaging of the loading and unloading state results in variable capacity output.

There are 2 key parts inside the compressor: compression mechanism (scroll sets) and the motor. In the inverter technology, the motor is changed and not the scrolls. In the Digital Scroll technology, the scrolls are operated differently and not the motor.