SPX Cooling Technologies Cooling Tower Marley MD - Manual (Page 23)

23
Maintenance
the plenum the rod retention is held in
place with fasteners. Loosen fastener
and slide the bracket away from the
adjusting rod. Turn the rod clockwise
to drive the motor away from the fan
(tighten belts) or counterclockwise to
drive the motor toward the fan (loosen
the belts). There is no need to loosen
any other hardware to adjust the belt
tension. After belt tension is adjusted
to a satisfactory position, install the rod
retention bracket with the thumbscrew
and replace any safety hoods.
Ideal tension is the lowest tension at which the belt will not slip under peak
load conditions. Check tension frequently during the first 24-48 hours of run-
in operation. Overtensioning shortens belt and bearing life. Keep belts free
from foreign material which may cause slipping. Never apply belt dressing
as this will damage the belt and cause early failure. Specific tools are made
to measure the tension of a V-belt drive system. A Dodge® V-Belt Tension
Tester, Browning® Belt Tension Checker or equivalent an alternative should
be used for tensioning V-belts. Check with you local belt supplier.
Belt tension is measured by applying a force perpendicular to the belt at the
center point between motor and fan sheaves. The belt should deflect
1 ⁄
64
of
the entire span, (measured sheave centerline to sheave centerline) when
the pressure shown in the table below is applied. Because belt tension is a
function of the motor sheave diameter, it is necessary to inspect the motor