Variable drives, Inspection, Maintenance – COOK CP User Manual

Page 6: Use of variable frequency drives, Motors, Grounding, Wiring, 30 minute interval, 8 hour interval, 24 hour interval

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6

• Bearings should be inspected as recommended in the

Lubrication Conditions Chart.• Inspect variable inlet
vanes for freedom of operation and excessive wear.
The vane position should agree with the position of the
control arm. As the variable inlet vanes close, the
entering air should spin in the same direction as the
wheel.

• Inspect springs and rubber isolators for deterioration

and replace as needed.

• Inspect for cleanliness. Clean exterior surfaces only.

Removing dust and grease on motor housing assures
proper motor cooling. Removing dirt from the wheel
and housing prevent imbalance and damage.

Lubrication - Fan Bearings

Greasable fan bearings are lubricated through a grease

fitting on the bearing.

For best results, lubricate the bearing while the fan is in

operation. Pump grease in slowly until a slight bead forms
around the bearing seals. Excessive grease can burst
seals thus reducing bearing life.

Before lubricating, the grease nipple and immediate

vicinity should be thoroughly cleaned without the use of
high pressure equipment. The grease should be supplied
slowly as the bearing rotates until fresh grease slips past
the seal. Excessive pressure should be avoided to prevent
seal damage.

In the event the bearing cannot be seen, use no more

than three injections with a hand-operated grease gun.

NOTICE! Loren Cook Company uses petroleum

lubricant in a lithium base. Other types of grease
should not be used unless the bearings and lines have
been flushed clean. If another type of grease is used, it
should be a lithium-based grease conforming to NLGI
grade 2 consistency. A NLGI grade 2 grease is a light
viscosity, low-torque, rust-inhibiting lubricant that is
water resistant. Its temperature range is from -30

F to

Exceptions to the greasing interval chart:

1. Periodic Applications (any break of one week or

more): it is recommended that full lubrication be
performed prior to each break in operation.

2. Higher Temperature: it is recommended to

halve the intervals for every 30

F increase in

operating temperature above 120

F not to

exceed 230

F for standard bearings; High Tem-

perature bearings (optional) can operate up to
400

F.

3. Vertical Shaft: it is recommended that the inter-

vals should be halved.

Lubrication Conditions Chart

Fan Class

Fan Status

Shaft Size

Maximum Interval

(operational hrs)

Centrifugal

Blower
Class I

Normal Conditions

(Clean, Dry & Smooth)

> 1-1/2”

10,000

< 1-1/2”

2,000

Extreme Conditions

(Dirty/Wet/Rough)

> 1-1/2”

2,000

< 1-1/2”

400

Centrifugal

Blower

Class II

Normal Conditions

(Clean, Dry & Smooth)

> 2”

7,500

< 2”

1,000

Extreme Conditions

(Dirty/Wet/Rough)

> 2”

1,500

< 2”

200

Centrifugal

Blower

Class III

Normal Conditions

(Clean, Dry & Smooth)

> 2”

3,000

< 2”

500

Extreme Conditions

(Dirty/Wet/Rough)

> 2”

500

< 2”

100

Use of Variable Frequency Drives

Motors

Motors that are to be operated using a Variable

Frequency Drive (VFD) must be VFD compatible. At a
minimum, this must be a Premium Efficiency motor with
Class F insulation. Motors that are not supplied by Loren
Cook Company should have the recommendation of the
motor manufacturer for use with a VFD.

Grounding

The fan frame, motor and VFD must be connected to a

common earth ground to prevent transient voltages from
damaging rotating elements.

Wiring

Line reactors may be required to reduce over-voltage

spikes in the motors. The motor manufacturer should be
consulted for recommended line impedence and usage of
line reactors or filters, if the lead length between the VFD
and the motor exceeds 10 feet (3m).

Fan

It is the responsibility of the installing body to perform

coast-down tests and identify any resonant frequencies
after the equipment is fully installed. These resonant
frequencies are to be removed from the operating range of
the fan by using the “skip frequency” function in the VFD
programming. Failure to remove resonant frequencies
from the operating range will decrease the operating life of
the fan and void the warranty.

Inspection

Inspection of the fan should be conducted at the first 30

minute, 8 hour and 24 hour intervals of satisfactory
operation. During the inspections, stop the fan and inspect
as per the Conditions Chart.

30 Minute Interval

Inspect bolts, setscrews, and motor mounting bolts.

Adjust and tighten as necessary.

8 Hour Interval

Inspect belt alignment and tension. Adjust and tighten as

necessary.

24 Hour Interval

Inspect belt tension, bolts, setscrews, and motor

mounting bolts. Adjust and tighten as necessary.

Maintenance

Establish a schedule for inspecting all parts of the fan.

The frequency of inspection depends on the operating
conditions and location of the fan.

Inspect fans exhausting corrosive or contaminated air

within the first month of operation. Fans exhausting
contaminated air (airborne abrasives) should be inspected
every three months.

Regular inspections are recommended for fans

exhausting non-contaminated air.

It is recommended the following inspection be conducted

twice per year.

• Inspect bolts and setscrews for tightness. Tighten as

necessary. Worn setscrews should be replaced
immediately.

• Inspect belt wear and alignment. Replace worn belts

with new belts and adjust alignment as needed. See
the Belt and Pulley Installation.

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