Twin-Lobe Air Blower Calculations Needed

I've witnessed the motor load of twin lobe blower with 'free discharge and closed (well, almost) discharge'. The motor load marginally varies. Then concluded the 'pneumatic load' is very less when compared with 'dynamic load' due the mass of lobes.

But for the internal leaks, lobe blower is a 'positive discharge' machine. So running with pinched discharge is not advisable even for testing. Care is to be taken to ensure the closing should not be full and not for a long duration. Otherwise this test will end up in a seizure.