JOHNSON CONTROLS
7
MAINTENANCE (CONTINUED)
Adjustable Motor Base
Belt drives can be aligned and adjusted by loosening clamping
bolts and sliding motor axially and retightening. Belt tension can
be fine tune adjusted by loosening or tightening the adjustment
bolts. Loosen clamping bolts first, then adjust adjusting bolts
and retighten clamping bolts. Belt tension is adjusted with the
adjusting bolts and maintained with the clamping bolts.
Fan Mechanical Balancing
Fan impellers are balanced statically and dynamically by
the factory, but may require further trim balancing. The final
installed vibration level of the fan is also dependent upon its
installation and foundation. Fans shipped completely assembled
have been trim balanced at the factory. Before any attempt is
made at balancing, check for any other causes of vibration or
unbalance as listed in the troubleshooting checklist.
A fan handling clean air should not need rebalancing after
original balance. Dust build-up on fan blades or wear can cause
fan unbalance. Periodic inspection of the fan should be made
to determine the amount of dirt build-up or wear. Portable
instruments are available that will indicate vibration in mils
(1 mil = 0.001 inches). Each fan has a Quality Assurance label
affixed to the fan. All pertinent information on factory balance is
recorded on the label for the owner’s information and use.
IMPORTANT NOTE: The fan must be checked and corrected
for any out of balance condition any time a component of the
rotating assembly is replaced or altered.
Lubrication of Anti-Friction Bearings
Bearings on assembled fans receive their initial lubrication from
the bearing manufacturer. Bearings shipped separate from the
fan or as a replacement may not be lubricated before shipment.
When there is the slightest doubt, the safe practice is to assume
that the bearing has not been lubricated. Always turn fan off
before lubricating. For grease lubricated ball or roller bearing
pillow block, a good grade of grease, free from chemically or
mechanically active material should be used. These greases are
a mixture of lubricating oil and a soap base to keep the oil in
suspension. They have an upper temperature limit where oil
and soap base oxidize and thermally decompose into a gummy
sludge.
Mixing of different lubricants is not recommended. If it is
necessary to change to a different grade, make or type of
lubricant, flush bearing thoroughly before changing. Regreasing
will vary from 3 months to a year depending on the hours of
operation, temperature and surrounding conditions. Special
greases may be required for a dirty or wet atmosphere (consult
your lubricant supplier).
When grease is added, use caution to prevent any dirt from
entering the bearing. The pipe plug or grease relief fitting should
be open when greasing to allow excess grease to flow out. The
pillow block should be about 1/3 full, as excess grease may cause
overheating. Use a low pressure gun.These ball bearing greases
or their equivalents are satisfactory for ambient temperatures
from 20°F to 200°F.
•
Chevron SRIU #2 (Standard Oil ofCalifornia)
•
Chevron BRB #2 (Standard Oil of California)
•
Premium RB (Texaco, Inc.)
•
Alvania No. 2 (Shell Oil Company)
Frequency of Lubrication
The bearings are lubricated at predetermined intervals and the
condition of the grease established as it is purged out of the
seals or by examination of the grease in the housing. An average
installation where the environmental conditions are clean and
room temperatures prevail may only require bearing lubrication
every 3 to 6 months, while operation in a dirty atmosphere at
high temperatures will require much more frequent intervals.