5
BEFORE START-UP:
Disconnect power to this unit
before servicing the unit.
1. Check to verify that the wheel is free to
rotate.
2. For optimum fan performance make sure
that the wheel to inlet venturi overlap
(0.25”) is maintained.
3. Verify that supply voltage on the line side
of disconnect agrees with voltage on fan
nameplate and is within the 10% utilization
voltage.
4. Apply power to unit and check rotation of
wheel with the directional arrow on the unit.
WARNING:
Rotation is critical. If
allowed to operate in the wrong
direction, the motor will overload and
bum out. Wheel rotation is clockwise
(CW) when viewed from the top
or drive side of the fan. Especially
check three-phase units for rotation.
For three-phase, rotation can be
changed by interchanging any two of
the three line leads. If unit is checked
on temporary wiring, it should
be rechecked when permanently
installed. Motor bum-out or tripped
overload protection devices are
usually the result of wrong rotation.
5. Electrical Input Check: Perform check of
fan ampere draw and verify that motor
nameplate amps are not exceeded. Take into
account the service factor range if the motor
is nameplated above a 1.0 service factor.
6. Fan RPM should be checked and verified with
a tachometer.
NOTE:
The fan should not need
balancing, as it was balanced at
the factory to be within stringent
vibration levels before shipment.
However, there are several things
that may cause vibration, such as
rough handling in shipment and
installation, weak foundations and
alignments.
V-Belts
V-belts on these belt driven fans are oil, heat,
and static resistant type and oversized for
continuous duty. With proper installation and
maintenance, years of operating efficiency can
be added to the lifespan of the V-belt drive.
The condition of V-belts and the amount of belt
tension should be checked prior to start-up
(see Figure1). When it becomes necessary
to adjust belt tension, do not over-tension as
bearing damage will occur. Recommended
belt tension should permit 1/64 deflection per
inch of span of the belt at the center of the
belt span. To find this point, measure halfway
between the pulley centerlines as shown in
Figure 2
. Extreme care must be exercised when
adjusting V-belts as not to misalign the pulleys.
Any misalignment will cause a sharp reduction
in belt life and will also produce squeaky,
annoying noises (see
Figure 3
). On units
equipped with 2 groove pulleys, adjustments
must be made so that there is equal tension on
all belts (see
Figure 4
).
1. When tensioning loosen the motor mounting
bolts and slide motor until proper tension is
obtained.
2. Always loosen tension adjustment enough
to place belts on sheaves without running
belts over the edge of either sheave. A new
belt may be seriously damaged internally by
careless handling (see
Figure 5
).
WARNING
: When removing or
installing belts, never force belts over
pulleys without loosening motor first
to relieve belt tension. The fan has
been checked for mechanical noises
at the factory prior to shipment. If
mechanical noise should develop, then
some suggestions are offered here as
a guide toward remedying the cause.
1. Check rotating members for adequate
clearance.
2. Check proper belt tension and pulley
alignment.
3. Check installation and anchoring.
4. Check fan bearings.
Figure 1.
Eliminate Slack
Figure 2.
Belt Deflection
Slack belts wear excessively, cause slippage
and deliver less power. For the longest belt life,
always provide proper tension.
