What does "50% Duty Cycle" mean?

What does "50% Duty Cycle" mean?

What does
If a compressor is turned on and running at a pressure of 10 bar. Whilst the compressor is being used the pump may not have to be on until the pressure drops to say 8 Bar. Then the compressor pump will turn on and increase the pressure till 10 bar is reached. The time the compressor is on compared to the time the compressor is turned off is the "duty cycle". So if the compressor is on as much as it is off then the duty cycle is 50%. 

Jinjing compressors are not designed to run higher than a 50% duty cycle. To prevent overheating, a thermal cut-out will turn the compressor off and then turn it back on when the compressor has cooled down enough to run again. 

In order to ensure that our screw compressor operates as efficiently as possible, Jinjing has independently developed its own special rotor profile. Compared with other traditional rotor profile designs, Jinjing rotor can save up to 15% energy.

Our precision machined large-size roller bearings help to make our air end have a long service life. All these, together with our state-of-the-art internal manufacturing processes and strict manufacturing tolerances, provide excellent quality synonymous with the Jinjing name.

Jinjing adopts an international advanced frequency conversion module, a special motor with speed up and down characteristics, and a set of PID parameters especially suitable for screw compressors. The control software has been tested by hundreds of thousands of compressors, with simple parameter settings and a friendly man-machine interface. The cooling of the frequency converter is specially designed. In order to support the user to set the best working pressure, the filtering area of the filter element of the oil-gas separator is increased.