Dessalator Duo 60 watermaker

[carlylelk]

I'm having a problem with my Duo 60.

Background: This watermaker has a 220V drive motor, a 24V drive motor, and a CAT 277 pump. The motors are attached to the pump on either side with a belt. The pulley on the pump has one-way (i.e. Sprag type) bearings, so when one motor is running the pulley on the pump, the other pulley is freewheeling so the other motor is not turning.

Problem: The Sprag bearings failed at 500 hours. They were GMN FKNS 6202 one-way bearings. I replaced them with CKS 206 P(X) one way bearings. They had basically the same Torque rating (148 NM vs 138 NM). One of the CSK bearings failed at only 20 hours.

It could be that the shop press fitting the bearings in the pulley ruined the bearing. But they failed the same way the GMN did, with grease exuding from the bearing and a "clatter" that happened in spurts.

Dessalator wants $900 for the two pulley/bearing assemblies. The CSK bearings were only $80. Since the torque ratings were almost the same, I'm not sure investing $900 is sane.

It could be the problem is the CAT pump is providing too much resistance and destroying the bearings, but the temperature of the pump was only about 100 degrees F, so it's hard to imagine there's something going on inside the pump.

Any suggestions?
Thanks,
Duane