Greenheck Fan 459968 manual Maintenance, Vibration

Deflection = Belt Span 64

11.If the fan has inlet vanes, they should be partially closed to reduce power requirements.

12.Fans with multi-speed motors should be checked on low speed during initial start-up.

13.Ensure proper wheel location for radial gap, overlap and alignment (see Radial Gap, Overlap & Alignment section on page 3).

14.Grease may be forced out of the bearing seals during initial start-up. This is a normal self- purging feature of the bearing.

15.Check for unusual noise, vibration or overheating of bearings. Refer to the Troubleshooting section of this manual if a problem develops.

Vibration

Excessive vibration is the most frequent problem experienced during initial start-up. Left unchecked, excessive vibration can cause a multitude of problems, including structural and/or component failure.

The most common sources of vibration are: Wheel unbalance

Drive pulley misalignment Incorrect belt tension Bearing misalignment Mechanical looseness Faulty belts

Drive component unbalance Poor inlet/outlet conditions Foundation stiffness

Many of these conditions can be discovered by careful observation. Refer to the Troubleshooting section

of this manual for corrective actions. If observation cannot locate the source of vibration, a qualified technician using vibration analysis equipment should be consulted. If the problem is wheel unbalance, in‑place balancing can be done providing there is access to the fan wheel. Any correction weights added to the wheel should be welded to either the wheel back (single-plane balance) or to the wheel back and wheel cone (two-plane balance).

Maintenance

WARNING

Disconnect and secure to the “Off” position all electrical power to the fan prior to inspection or servicing. Failure to comply with this safety precaution could result in serious injury or death.

Once the unit has been put into operation, a routine maintenance schedule should be set up to accomplish the following:

1.Lubrication of bearings and motor.

2.Variable inlet vanes should be checked for freedom of operation and wear.

3.Wheel, housing, bolts and set screws on the entire fan should be checked for tightness.

4.Any dirt accumulation on the wheel or in the housing should be removed to prevent unbalance and possible damage.

5.Isolation bases should be checked for freedom of movement and the bolts for tightness. Springs should be checked for breaks and fatigue. Rubber isolators should be checked for deterioration.

6.Inspect fan impeller and housing looking for fatigue, corrosion or wear.

WARNING

Changing the belts or drives can significantly increase the amp draw of the motor. If changes are made to the drives or belts, the amps must be checked to assure no overamping.

V-Belt Drives

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, ensure 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. Belts are adjusted by raising or lowering the motor pivot plate. For initial tensioning, the proper belt deflection half-way between sheave centers is 1/64 of the belt span. For example, if the belt span is 64 inches, the belt deflection should be 1 inch using moderate thumb pressure at mid-point of the drive. Check belt tension two times during the first 24 hours of operation and periodically thereafter.

Belt Span

®

Models TCF and Model QEI/QEID Centrifugal 5