Agitators - Constant or Variable Torque
Agitators - Constant or Variable Torque
(OP)
I was always under the impression that agitators were to be categorized as constant torque applications. However, per this website, agitators tend to have this speed-torque curve which indicates that they are variable torque. Can anyone elaborate on this?
http://cipco.apogee.net/mnd/meavovr.asp
http://cipco.apogee.net/mnd/meavovr.asp





RE: Agitators - Constant or Variable Torque
This is a good paper describing agitator applications. Although it doesn't specifically address your question, you can get from it the idea that there are a lot of variables involved. Bottom line, that article you referenced said "many" agitators and mixers, but by all means not all of them.
http:/
RE: Agitators - Constant or Variable Torque
If you go for the classic "variable torque" designed VFD, you will often find the ability to start a high load has been sacrificed for overall higher power capability but lower overload.
That's a great document by Reliance btw.
RE: Agitators - Constant or Variable Torque
That is simply due to the ability of the operator or process setup people to load to the maximum over a broad spectrum of process materials usually---thus, the agitator assembly will see full capacity regardless of the speed it is to be operated at.
That pretty-well defines a constant torque application when I am asked to specify equipment.
Just an aside on this subject--- batch process agitators make excellent "trick" questions on drive application examinations just for the above reasons!
RE: Agitators - Constant or Variable Torque
If the viscosity changes a specific analysis is required to define the motor torque requirements.