Motor speed – Burr King Model 720 User Manual
Page 9
Picture 3: shown is a variable speed controller (optional) and the air/belt controls mounted in a console (optional). Standard configuration
has the controls machine mounted.
6. Using the air pressure regulator control located on the incoming air filter assembly (see picture), adjust
the air pressure for air pressure delivery of from 20 to 50 PSI. The greater the air pressure, the greater the
belt tension.
7. Open the guard door, RELEASE the probe and install the abrasive belt. Center the belt on the wheels.
Keep clear of the belt and wheels and ENGAGE the probe. The probe will move outward and place the
belt under tension.
8. Engage the motor by placing the ON/OFF switch to ON. The belt should rotate smoothly in a CCW
direction about the machine wheel belt path as you face the left side of the machine (guard door). If
either of these conditions are not met turn the machine OFF immediately.
a. If the abrasive belt does not remain centered on the contact wheel adjust belt tracking by using
the Allen cap screw on the left side of the probe (see picture 4). Adjust this screw either CW or
CCW as required to center the belt on the belt track. Once this control is adjusted it will seldom
require re-adjustment.
Picture 4: Note Allen cap screw. Use this control to adjust the belt tracking.
b. If the machine belt tensions, and tracks properly, but has excessive vibration turn the machine
OFF and call the Burr King factory for assistance.
Important note about small nose wheel diameters
VS
motor speed
The model 720 is available in fixed and variable belt speed models. The drive wheel of the fixed speed
model turns at 3450 RMP which is a standard electric motor speed. Using nose wheels smaller than 1 ½ in
diameter is not recommended on fixed speed models as the resultant nose wheel rpm may exceed the speed
rating of the nose wheel bearings thus shortening wheel life.
Variable speed motor control allows reduction in drive wheel speed thereby reducing the stress on small
diameter wheels. For longer nose wheel service life use the following relationships:
Nose wheel diameter (inches)
Variable speed % of maximum
0.5
or
less
25%
0.6
to
1.0 33%
1.1
to
1.5 75%
1.6
and
larger
100%
The model 720 will accept nose wheels to 4 inches in diameter.
Maintenance procedures for the model 720
FIRST DISCONNECT THE MACHINE FROM ITS AC POWER SOURCE.
* Routinely vacuum or otherwise remove dust and debris build-up from the machine and the machine belt
track.
* Routinely inspect for loose screws and other hardware. Tighten as required.
* Routinely inspect the air pressure assembly bowls for water/oil build up and drain as required using the
facilities provided.
* There are no other maintenance actions required. All bearings are sealed for life and require no additional
lubrication.
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www.burrking.com
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us
at
DOC720OP-99 REV10/02
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