Greenheck Housed Plenum Array , Plug and Plenum Fans (475405) - Manual (Page 12)

12 Housed Plenum Array, Plug and Plenum
Variable Frequency Drive Operation
For operation with Variable Frequency Drive (VFD),
always check motor amps when adjusting the operating
frequency. Motor may be sized for the original selected
operating speed under 60 Hz. Bypassing the VFD
or increasing the speed from this original selection,
even if less than 60 Hz, may cause motor overload or
failure. Consult factory–with fan serial number–before
increasing the upper limiting frequency.
Always check the fan rpm when adjusting the operating
frequency. Do not exceed maximum class fan rpm of
the wheel.
Belt Span
Deflection = Belt Span
64
Belt Drive Maintenance
V-belt drives must be checked on a regular basis
for wear, tension, alignment and dirt accumulation.
Premature or frequent belt failures can be caused by
improper belt tension, (either too loose or too tight)
or misaligned sheaves. Abnormally high belt tension
or drive misalignment will cause excessive bearing
loads and may result in failure of the fan and/or motor
bearings. Conversely, loose belts will cause squealing
on start-up, excessive belt flutter, slippage, and
overheated sheaves. Either excessively loose or tight
belts may cause fan vibration.
When replacing V-belts on multiple groove drives all
belts should be changed to provide uniform drive
loading. Do not pry belts on or off the sheave. Loosen
belt tension until belts can be removed by simply lifting
the belts off the sheaves. After replacing belts, insure
that slack in each belt is on the same side of the drive.
Belt dressing should never be used.
Do not install new belts on worn sheaves. If the sheaves
have grooves worn in them, they must be replaced
before new belts are installed.
The proper tension for operating a V-belt drive is
the lowest tension at which the belts will not slip at
peak load conditions. Belt are adjusted by raising or
lowering the motor
pivot plate. For
initial tensioning,
the proper belt
deflection halfway
between sheave
centers is 1/64-inch
per each inch of belt
span.
For more information about measuring belt tension,
refer to Greenheck’s Product Application Guide, FA/127-
11, Measuring Belt Tension, found online at www.
greenheck.com in the library section.
Check belt tension before start up and after the first
24 hours of operation. The belt tension should also
be checked periodically thereafter.
Shaft Bearings
The bearings for Greenheck fans are carefully selected
to match the maximum load and operating conditions
of the specific class, arrangement, and fan size. The
instructions provided in this manual and those provided
by the bearing manufacturer, will minimize any bearing
problems. Bearings are the most critical moving part
of the fan, therefore special care is required when
mounting them on the unit and maintaining them.
Refer to the following chart and the manufacturers
instructions for grease types and intervals for various
operating conditions. Never mix greases made with
different bases. This will cause a breakdown of the
grease and possible failure of the bearing.
Recommended Bearing Lubrication Schedule
Relubrication Schedule in Months*
Fan
RPM
Bearing Bore (inches)
1 ⁄
2
-
1
1 1 ⁄
8
-
1 1 ⁄
2
1 5 ⁄
8
-
1 7 ⁄
8
1 15 ⁄
16
-
2 3 ⁄
16
2 7 ⁄
16
- 3
3 3 ⁄
16
-
3 1 ⁄
2
3 15 ⁄
16
-
4 1 ⁄
2
4 15 ⁄
16
-
5 1 ⁄
2
To 250 12 12 12 12 12 12 10 8
500 12 12 11 10 8 7 5 4
750 12 9 8 7 6 4 3 2
1000 12 7 6 5 4 3 2 1
1250 12 6 5 4 3 2 1 .5
1500 12 5 4 3 2 1 .75
2000 12 3 3 2 1 .5 .25
2500 12 2 2 1 .5 .25
3000 12 2 1 .5 .25
3500 12 1 .5 .25
4000 12 .5 .25
5000 12 .25
Number
of shots**
4 8 8 10 16 25 41 57
* Lubrication interval is based on 12 hour day operation and
maximum 160˚F housing temperature.
For 24 hour per day operation, the interval should be cut in
half.
** Lubricant should be added with the shaft rotating and
until clean grease is seen purging from the bearing. The
lubrication interval may be modified based on the condition
of the purged grease. If bearing is not visible to observe
purged grease, lubricate with number of shots indicated for
bore size.
• For conditions including high temperatures, moisture, dirt
or excessive vibration, consult the factory for a specific
lubrication interval for your application.
• Lubricant should be a high quality lithium complex grease
conforming to NLGI Grade 2. Factory recommends Mobilux
EP-2 or synthetic Mobilith SHC100.
• The use of synthetic lubricants will increase lubrication
intervals by approximately three times.
• Storage periods of three months or longer require monthly
rotation of the shaft and purging grease prior to storage and
start-up.