The duty cycle (work cycle) of a compressor is that it will pump up to a specific pressure (eg. 8 bar or 120 psi) and then turn off. When the pressure in the tank falls below a set threshold (eg. 6 bar or 87 psi) it will turn on again and pump back up to the max holding pressure (eg. 8 bar or 120 psi). The total running time of the pump should not exceed 50% of the time that you are using the compressor.
For example if the compressor cycle time was 10 minutes and ran for 5 of those minutes this would be 50% duty cycle.
Engineers tip: The trick is to make the motor run as little as possible and rely on the stored pressure rather than consuming generated pressure.
Bambi air compressors are 50% duty cycle and suitable for almost all applications.
Cattani air compressors are 100% duty cycle and suitable for all dental applications.