COOK Automatic Belt Tensioner Supplement II - Manual

AWB, EWB, XLWH, XMWH, APB, EPB, XLPH, XLWH, H-Series, ETE, ETS,
LXU, LEU, and LTU Units - Sizes 20 to 72
INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Automatic Belt Tensioner Supplement II
This publication contains the installation, operation
and maintenance instructions for the Automatic Belt
Tensioner.
Carefully read this publication prior to any installation
or maintenance procedure.
Loren Cook brochure, Automatic Belt Tensioner, provides
additional information describing the equipment, fan perfor-
mance, available accessories, and specification data.
For additional safety information, refer to AMCA publica-
tion 410-96, Safety Practices for Users and Installers of
Industrial and Commercial Fans.
All of the publications listed above can be obtained from
Loren Cook Company by phoning (417)869-6474, extension
166; by FAX at (417)832-9431; or by e-mail at info@loren-
cook.com.
For information and instructions on special equipment,
contact Loren Cook Company at (417)869-6474. The Auto-
matic Belt Tensioner uses sealed bearings which do not
require maintenance and contains no user-serviceable
parts. Do not disassemble the belt tensioner.
Belt Tensioner Mounting Instructions
Unit Sizes 20 - 36:
1. Fasten mounting bracket to outside surface of bearing
support plate using 2 wizz bolts and nuts through the
upper slot as shown. Adjust bracket to lowest point and
tighten mounting bolts fully.
2. Set belt tensioner assembly on top surface of the
bracket and line up with hole. Bring a 3/8-16 x 1-1/4 bolt
through the hole and thread it into the bottom of the ten-
sioner.
Unit Sizes 42 - 72:
1. Fasten belt tensioner motor plate to the bearing support
plate using 8 wizz bolts and nuts as shown.
2. Set belt tensioner assembly on the top flange of the
motor plate and line up with inside hole (use outside
hole for 20” sheaves and larger). Bring a 3/8-16 x 1-1/4
bolt (7/16-14 for RT4000) through the hole and thread it
into the bottom of the tensioner.
Belt Tensioner Alignment and Tensioning Instructions for
Clockwise Units:
1. Tighten the bolt finger tight allowing tensioner assembly to
rotate freely.
2. Align driver and driven sheaves with tensioner idler pulley.
3. Install belt around all sheaves and rotate tensioner coun-
terclockwise (clockwise for counter clockwise units) until
belt feels tight and you feel light spring tension.
4. While holding tensioner at this position, use a marking
pencil to make an alignment mark on the tensioner and
the outboard bearing support so that the tensioner can be
rotated back to the mark after removing the belt.
5. Remove the belt and realign the marks on the tensioner.
Now rotate the belt tensioner assembly counterclockwise
(clockwise for counter clockwise units) until the alignment
marks are spaced approximately 1/2” to 3/4” apart.
6. Tighten mounting bolt fully and install belt by wrapping it
around tensioner idler pulley. Use palm of hand and rotate
tensioner arm clockwise (counterclockwise for counter
clockwise units) until there is enough slack in the belt to
allow it to slip over the driver pulley and then the driven
pulley. If using RT4000 tensioner and spring force is to
much to rotate tensioner arm enough to install belts by
hand, use procedure given in Notes 2 & 3.
7. Check belt tension by pushing on the belt on the tension
side. Note that the tensioner will move in as more force is
applied by pushing on the belt. Hold the end of the belt
tensioner arm stationary with firm hand pressure and push
on the belt again. If the tension feels right and the ten-
sioner arm doesn’t move with an equal amount of force
applied, then the tension should be correct. If there is any
doubt that the tension is correct, check it by starting the
fan and listening for belt squeal. If excessive belt squeal is
heard - loosen tensioner mounting bolt, and rotate ten-
Automatic Belt Tensioner
BELT TENSIONER IDENTIFICATION DETAIL
BI-DIRECTIONAL
TENSIONER
DIRECTIONAL ARROW
(SEE RT3000/RT4000
INSTALLATION NOTES)
DIRECTIONAL ARROW
(SEE RT3000/RT4000
INSTALLATION NOTES)
RT1000 WITH
1 GROOVE “A”
BELT IDLER
RT3000 WITH
2 GROOVE “A”
BELT IDLER
RT4000 WITH
2 GROOVE “B”
BELT IDLER
Caution:
Do not use the top assembly nut to add additional ten-
sion as this may potentially cause damge the ten-
sioner. It must be re-positioned per tensioning
assembly instructions.