Large 8-pole induction motor for slow speed application 7

[HenryOhm]

All,

I am investigating the upgrade of an old 5,000Hp 150rpm DC motor to AC for a pump application. Am curious about an "off-the-shelf" induction machine operating off PWM versus synchronous due to up-front price. Appears that an 8-pole induction machine is not stretching this too far but would like to avoid a reduction gear if possible. I assume a PWM could be operated only in the 0-10Hz range to effectively operate an 8-pole 900rpm machine as a 150rpm motor? But, what will be the downsides? Low end speed regulation, how the torque curve may be affected, upstream harmonics...? Does an AFE affect the equation?

Any information including reference materials or whitepapers that might help would be great appreciated.

Thanks!

 

[gsimson]

Thanks for the very useful information given about the probable applications. All Electrical Systems are interlinked with certain application. Hence our solutions should always consider the requirements of final application.