Double check your direction of rotation

If the duct/piping on discharge has changed, or the inlet conditions have changed, it can cause the fan the "run off the curve" and draw high amps. Is there a blockage in the discharge or suction? Rotary valve?

Is the current balanced on all 3 phases? voltage balanced? connected correctly for the right voltage of operation?

To get the same results with both replaced sounds like system/process related.

Dave

dear Dave

direction of rotation is ok

duct/piping no change or blockage

Rotary valve I don't know what you mean by that

all 3 phases I will check with electrician gays

system/process thy do some calculation but don't tell us what the resalt

thanks

moayyad

dear Dave

we check everything as you described and did not find anything wrong any advice can you help me with

(We tried to operate the blower and get the same resalt)

Very little details to help troubleshoot, changing blower bearings, positive displacement roots type blower correct?

Is the motor connected proper for the voltage you are supplying to it, you state motor amps are high and not getting up to speed is an indication of wrong motor connection or shorted windings, you most likely will want to double check this. All three phases have balance voltage and current?

https://electricmotorwarehouse...connection-diagrams/

Mechanical drag, rubbing rotors, worn out gears can all cause high motor amps. You state you changed the blower and the motor and still have a problem. Common to this comment, the motor connection wiring, direction of rotation, wrong HP motor, wrong blower. If the blower and motor are in good condition then mechanical drag can be eliminated.

If the process changed, someone forgot to remove a blank in piping, etc this would reflect as a motor amp change.

Dave

This is positive displacement blower. If no rubbing in the machine and motor also is good, then the most likely thing is a clogged suction / discharge line which is causing high load. Is It possible that any valve on the lines is not opened ?

Maybe could you try to start the blower after disconnecting the discharge line ( removing expansion joint at blower outlet) to identity the real cause.

Thanks.