Block suction, or blocked discharged would reduced the load, or the load current, as motor speed(4% variation from no load to full load) would increased little.Motor active power(W=VICos phi) would reduced. Reactive power(VAR=VISin phi) would increased, little. Motor total current(It=Im+Iw vector) would reduced. Motor power factor would reduced as phi increased. Motor efficiency would reduced, as motor load reduced in blocked suction or discharged, it cannot be discriminated by loading.......

Thanks Dr. Desai. This is exactly what I expect based on fundamentals. Well, is there any difference if the blocking is at suction or discharge regarding these observations? or both equally decrease the power, the current, the power factor and increase the speed and the reactive power?

the effect of suction or delivery blockage depends on the blower type. please check the two main types, axial blower and radial blower. each has different behavior,. you can search these two types and easy to understand the suction and delivery blockage effect as they are opposite.

The main differences between axial and radial are related to the flow rate and outlet pressure. Axial types best suites applications that require high flow rate at less pressure (and input power), while radial type (centrifugal) well meets the requirement of the applications that require higher output pressure. It can be expected from this that the drop of input power (current and power factor) in centrifugal flow (radial) blower may be less than that of an axial flow blower of same rating due to blockage, but both certainly will exhibit a drop of power due to blocking the air flow

check one is affected by blockage inlet and the other is not.