Pump questions...and filter sand.

[Poconos]

Sorry I missed this thread but I've been occupied with other issues recently and sometimes neglect the forum. Don't know of any general information sites for motors but they are actually pretty simple devices. May try howstuffworks.com and see what's there. I'll throw in a few basics that should be true of most pump motors. There is a picture of the back end of a Hayward superpump in this thread:
http://www.poolforum.com/pf2/showthread.php?t=4800

-- AC motors usually have two windings. Starter and running.
-- An internal thermal circuit breaker is usually present too.
-- The running winding is always connected to the AC line and the starting usually has a centrifugal switch and capacitor in series with it.
-- The starting winding is designed to provide a high starting torque to get the motor up to speed and overcome initial loads on the motor.
--When the motor is stopped the switch is closed and the capacitor in series with the starting winding provides a electrical phase shift relative to the running circuit to get the thing started in the proper direction.
-- When up to speed the switch opens and disconnects the starting winding.
-- The impedance (resistance) of the starting circuit is quite a bit lower than the running circuit thus a high inrush current.
-- Some problems and results:
-- Open switch , open capacitor, or open starting winding-- Motor will not start, low level hum, will eventually overheat, circuit breaker or internal thermal switch will eventually open.
-- Shorted starting capacitor -- Motor will not start, loud hum, circuit breaker will pop quickly if the internal thermal breaker doesn't open first.
-- Shorted turns on either winding -- Motor will probably start and run, maybe not up to speed, but smoke and smell will follow shortly.
-- Open running winding -- I think the result will be similar to a shorted starting capacitor.
These should cover most of the problems one is likely to encounter. I have also advised to keep pumps out of the weather if possible. The reason is even though they are designed for outdoor use, they will suck moisture in the form of water droplets in with the cooling air and this moisture will eventually corrode bolts and other hardware making disassembly a pain. Someone did mention some kind of cover that was at some pool store. Open at both ends as I recall for proper ventilation. Also keeps the sun off so it will run a little cooler.
Anyone please feel free to add their comments and wisdom and correct any mistakes I may have made.
Al