Old GE 405TS rewound for 150hp (1800rpm)

[stankap3]

All,
At work we are using an old GE drip proof motor 405TS (no fan)on a pump (circa 1969). It used to be a 125hp with a 1.15 SF. It is now 150hp with a 1.0 SF. It has greased sleeve bearings. The pump draws 145 to 150hp. The temp at the end bells is 140 to 160F on the surface. Is this too hot for the motor? It says on the old data sheet the it has a amb. temp 40C and a temp rise of 90C. Making the max temp about 266F. I assume that is internal temp. What would that correspond to on the outside of the motor? Is it safe to run like this or should we buy a new motor?

Thanks in advance,
Stan

 

[electricpete]

I don't see anything to suggest concern for the windings. You can't really tell what winding temperature is from this info.

I might be a little concerned about the grease life. If housing temperature is 140-160F then bearing temperature is probably 160-180F. Virtually all greases are designed for 200F plus, but grease life could be limited.

By the way, greased sleeve bearing is unusual. I don't have any experience with those.

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[stankap3]

Pete,
I have no way of measuring the winding temps, but last year in the summer with a smaller impeller in the pump (112hp vs. 150hp now) the motor casing temp was about 140 max. I expect 20F rise with the larger hp draw.

What does the max. temp rise of 90C mean, when ambient is 40C? Is that max temp limit the inside winding temp?

Stan

 

[edison123]

Stan - Yes, that 90 deg C rise the actual temp rise of winding when measured with embedded winding RTD's/Thermistors. The motor body temperature is not indicative of winding temperature.

Muthu

http://www.edison.co.in