11
ing Technologies does not assume responsibility for any technical
support or damages for problems associate with non-Marley brand
VFD systems.
Changing the operational fan speed from the factory settings could
cause the fan to operate in an unstable region which may result
in damage to the equipment and possible injury. Warranty is void
if the cooling tower is operated at speeds which cause damaging
vibrations to the cooling tower and associated equipment. When
utilizing a variable frequency drive, the cooling tower must be tested
across the full range of speeds and checked against CTI guidelines
for excessive vibration. Speed ranges not meeting these guidelines
must be locked out in the VFD.
Mechanical Equipment:
Always shut off electrical power to the fan motor prior to perform-
ing any maintenance on the tower. Any electrical switches should
be locked out and tagged out to prevent others from turning the
power back on.
1. Spin the fan manually to assure that all fan blades properly clear the inside
of the fan cylinder. Observe the action of the sheaves and belts to be sure
that the motor is properly aligned with the fan sheave. If necessary, cor-
rect the alignment in accordance with the Belt Tensioning and Sheave
Alignment section on pages 21 and 24.
The following steps require operation of the fan motor while the access
door is open. DO NOT view the fan operation from near or inside the
access door location. Fan rotation should be viewed from tower grade.
The access door should NOT be opened while the fan is operating.
The fan rotation causes a negative pressure inside the cooling tower
and will abruptly pull the door open should access be attempted. Only
open the cooling tower access door when the fan is off and locked out.
2. Momentarily bump (energize) the motor and observe rotation of the fan.
The fan should rotate in a counterclockwise direction when viewed from
below. If rotation is backwards, shut off the fan and reverse two of the
three primary leads supplying power to the motor.
Warning
Warning
Caution
installation
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