Submersible motor minimum speed

[Pucp]

Hi, I need to know the minimum speed for a 300HP Hitachi (1740 rpm) submersible motor that work with a frequency converter. This motor is used with a 11 stage deepwell pump. Somebody tell me that it is at maximum 80% of its nominal speed, this is, he said, because with less speed the axial bearing of the motor will not be well lubricated. Is there a problem with this bearing? or with something else?. I have the nameplate data: Model B01, 307 A, 460 V, 300 HP, 1740 rpm. Thanks in advance.

 

[busbar]

http://www.vanet.hitachi.co.jp/public/Div/iced/english/products/motor/sub_wire/main.htm

lists a minimum flow of 0.5 ft/sec, so it looks like determination of safe minimum speed would be based partly on well/motor dimensions.

 

[buzzp]

The motor needs fluid flow to keep it cool. This minimum pump speed for adequate flow will be based partly on the temperature of the fluid and the size of the pump. I haven't checked the suggested site but it appears to link to the mfg. Good luck.

 

[jbartos]

Suggestion: Check with manufacturers, e.g.

http://www.submersibles.co.uk/products.html

http://electricboat.com/serv02.htm

etc. for more info