l1/Z” A P P R X (13mm)
MOTOR
PULLEY
1938
Fig. 2.
BELT ADJUSTMENT
Hand pressure should depress the belt about 1/2 inch.
See Figure 2. The belt should be tight enough so that no
slipping occurs. A belt that is unnecessarily tight can
cause excessive wear.
Adjust belt tension by loosening the motor hold-
down bolts, moving the motor until tension is correct.
Then retighten the bolts. Make certain that belts and
pulleys are aligned properly. If a belt becomes worn or
frayed, replace it.
PRESSURES
When making weekly maintenance checks, verify that
the tank pressure is in the 70 to 90 psi (480 to 620 kPa)
range. Also make certain that the PRV pressure for
each
unit is at the proper setting.
COMPRESSOR OPERATION
As part of the weekly operational check, confirm that
the compressor does
have
an “off" period and is not
running continuously. Note that on WP240 Compressors,
the manual alternation system should be switched over
to confirm the start-up and off cycle of both pumps.
Every three months, the cut-in pressure, pump up
time, cut-out pressure, and off time should be measured
under normal operating conditions. It should be below
50 percent operation, that is, it should have more off
time than on time. It should operate approximately
from 70 to 90 psi (480 to 620 kPa) on the 1/4 to 5 HP
units and from 60 to 100 psi (415 to 690 kPa) on the
7-l/2 to 20 HP units. Note that on the WP240 units,
the
pumps should be switched and rechecked (switching is
automatic on some units).
A good maintenance practice is to keep
these
figures
for practice. If possible, attach a card with the figures to
the device. Decreasing off periods with no change in the
pressure range indicate an increase in air consumption,
Pump up times will increase also. This can be caused by
added devices or leaks. Increasing pump up time with
no
change in the pressure range or off time indicates wear in
the compressor and may warrant closer observation, This
is usually followed by an increase in oil consumption.
If there is suspicion of wear, the dead ended pump
up time (pumping up the tank with the system shut off)
should be checked against the value given in the data
table. If it differs from the data table by more than 10
percent, then an analysis of the cause should be made
and the situation corrected. Refer to the WP240 Wiring
Diagrams and the WP250 Wiring Diagrams for operation
unique to these models.
TROUBLESHOOTING
ROTATION OF FLYWHEEL
MUST BE IN THE SAME
DIRECTION AS THE
\
OIL
PRESSURE
GAGE
WRONG OIL PRESSURE
Normal oil pressure for these compressors is from 10
to 20 psi (70 to 140 kPa). There should be no pressure
during the “Off” cycle. Check the oil level and clean the
oil intake filter before adjusting pressure. The oil pres-
sure is regulated by a spring loaded ball that is mounted
in the bearing carrier or in the crankcase near the bearing
carrier. See Figure 3, This is on the same side as the dip-
stick. The spring pressure is controlled by an adjusting
screw. Turning the screw inward will increase the pres-
sure.
Be sure to loosen the adjustment lock nut before
making any adjustment. Turn the adjustment screw
slowly until the oil gauge registers approximately 1.5 psi
(105 kPa). After the adjustment has been made, tighten
the adjustment screw lock nut.
75-7131
Summary of Contents for WP230A-M
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