8
Pump Motors
Level 2
A.O.Smith
In the past when brass pumps were common,
the use of motors with cast iron instead of alu-
minum end frames was common.
The cast iron
has less reaction with the brass. Today, most
pumps are plastic so this is not a concern.
Small above ground pumps have a sealed
motor/pump unit which is not repairable. Motors
on the other applications are easily identified by
the type of end frame and shaft extension.
NEMA 56C face (56C and 56J) and square flange
motors are common on in-ground pool pump
applications. Many above ground pool pumps
and jetted tubs use the motor through bolts to
secure the pump to the motor. The motors have a
“Y” after the frame designation on the nameplate
indicating a non-standard mount. Even though
the mount is not standard per NEMA, it has
become standard among the pump manufactur-
ers. Spas and jetted tubs may sometimes be sim-
ilar in looks and construction with the distinction
that the water is normally drained from a jetted
tub after each use. Spas use NEMA C, square
flange and thru bolt mount motors.
Two speed motors are common on single pump
spas. High speed is used for the invigorating jet
action, and low speed is used to circulate water
when the heater is on. Less common is the use of
two speed motors on swimming pools. The unit is
run on high speed several hours a day for maxi-
mum filtration action and then switched to low
speed and run continuously. Some filtration
action does occur on low speed and a better
chemical balance is maintained. Total electrical
and chemical consumption may be reduced.
SK1072
ST1072
SQ1152
CBS2072
