We have a durco centrifugal pump that keeps tripping on high amps (37 vs designed at 22)... (20 hp, 192 tdh, 3600 rpm, the pumped solvent fluid viscosity is sometimes that of water but today it was "syrupy" and cooled). There have historically been problems with NPSH--however, with the tank level at 70% not the case.
The vibration readings previously led us to believe we needed to "hot" align after we changed out the motor. The motor has sealed bearings and was changed out today, however, vibration is not the issue and NO change in the symptoms. When we throttle back the discharge valves the amperage goes down but the process needs more flow. The inline steam exchanger could not be used as the amps would hold for 30 min on throttled valves and then heat up without the hx in service.
the pump housing seal fluid hoses have air fins after noting a temp of 598F months ago. we need to check this pump housing temp again.
I have noted the Thread407-59159 posting "during the motor inspection, it was found that the rotor was bowed and unbalanced (was not shown in the vibration spec) and grease was found on the windings. bearings were overgreased"... we will look into this possibility, however, since the motor when uncoupled did not have any increas in amps and have had two motors now tried and no success or change in symptoms...we are still puzzled.
any suggestions what to attempt next...