Reed Electric

Mystery of the Missing Fan

A costly problem we run across occasionally involves a missing part. Some Reliance and GE 2-pole (3600RPM) TEFC (totally-enclosed fan-cooled) motors have very long stator designs. This length puts the drive-end bearing far away from the air stream of the cooling fan. To cool the drive-end bearing, these designs incorporate a small, thin fan mounted on the drive-end with a flat sheet metal guard.
This design works rather well… until…..
Because the fan is small and fragile, they occasionally get broken or lost over the years. And when they are not replaced, it is difficult to visually detect that these fans were originally installed on the motor. These small odd drive-end fans are nothing like the big Main Motor Cooling fans that are always on a TEFC motor.

 What then happens is the drive-end bearing runs much hotter and has a shortened life. A motor that had provided successful service for years, suddenly just doesn’t seem to hold up like it used to. And the culprit is a $50 to $100 Missing Fan.

electric motor fanTips:

Check your 3600RPM motors for a drive-end fan before sending out for repair to make sure that any with a bearing fan are returned with this fan

If you have a 3600RPM motor that:
        You just can’t keep grease in – it runs out
        Has a drive-end bearing that is running much hotter than it used to
        You just can’t keep bearings in

Then you may have one of these designs that are now missing the little drive-end bearing fan setup. Look on the drive-end endbell exterior for screw holes that would have been used to mount the drive-end fan guard. This would be your clue to the Mystery of the Missing Fan.

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Reed Electric - LA
5503 S. Boyle Avenue, Los Angeles, CA 90058
Ph: 323-587-2284 / Fax: 323-587-2142

Reed Electric - Reno
5375 Louie Lane, Reno, NV 89511
Phone: 775-824-7333 / Fax: 775-824-7344