NEMA Premium and IE3 for submerged motors
NEMA Premium and IE3 for submerged motors
(OP)
Does anyone have an understanding of how NEMA Premium and IE3 standards will effect submerged motors? In particular, I'm referring to a motor submerged in hydraulic fluid as a pump for a hydraulic power unit. Internet searches show "Motors completely integrated into a machine (pump, fan, or compressor) that cannot be tested separately from the machine" are exempt from the standards. Of course how reliable are internet searches?





RE: NEMA Premium and IE3 for submerged motors
RE: NEMA Premium and IE3 for submerged motors
RE: NEMA Premium and IE3 for submerged motors
I have designed fluid filled motors for mainly operation in ocean conditions, but have also done some for other fluids, including hydraulic fluid. The smallest has been about 2.5 Hp. The motors are sealed, but the purpose of that seal is to keep various junk in the ambient fluid from entering the motor, and to keep the internal fluid in the motor during transport, storage and installation. The manufacturer of the motor should be able to test it, even if the motor uses the pump as its mounting cover and seal (have made some like this before). The tests need to be modified for the special circumstances of the motor. Of course, normal efficiency and other running data will be different for the fluid filled when compared to the same size standard motor.
RE: NEMA Premium and IE3 for submerged motors
RE: NEMA Premium and IE3 for submerged motors
RE: NEMA Premium and IE3 for submerged motors
If you want to increase system efficiency, you should consider applying VFD (unless you already do off course). In a large range of application, where speed control does not make sense, pumps are often throttled to match the flow exactly to the requirement. In some cases the valve might be 20% closed, so open the valve fully, reduce the speed and you will save more energy and your VFD is paid back in less than 2 years. You can read about such a case here. While the characteritics of hydraulic fluid is different from water the physics still apply, although realised energy saving will be slightly different.
If you can then improve your controls to take advantage of the speed control, off course payback is even shorter
Another thing is that permanent magnet motors are often referred to as "Super Premium" or IE4 motors, but we are introducing a new motor mounted drive this year and wanted and IE4 motor for this and many of the PM motors we investigated, where only IE3 and some even IE2, so make sure you do not select a new motor based on motor technology, but do it based on data from the manufacturer and even then I would advise testing the performance as well.