13
AP Dynamometer Service Manual
Minor scratches and dents may be removed from AP Dynamometer pres-
sure bars using the following criteria and guidelines:
1.
This type of action may not take place in any one location more than
once during the life of the unit. Use a Dremmel type drum, flexible disk,
or buffer attachments to remove scratches and dents. No more than
.005 inch may be removed from the surface of the pressure bar.
2.
The grit of the tool must be fine enough that the result is no worse than
a 63 microinch surface finish.
3.
On square corners, material may be removed to a depth of 1/16 inch
as measured from the corner, due to these areas being at very low
stress levels during use. Blunt dents less than 1/16 inch deep from the
corner do not require removal for safe operation.
4.
The serial number and traceability information is stamped near one of
these low stress corners. Do not use a material removal tool in the
area of these stamped numbers in order to maintain traceability.
Repair by welding is not authorized.
The Dillon Model AP mechanical dynamometer may be subjected to 150%
proof loads of the rated capacity up to twice per year for inspection pur-
poses. The applied loads must not exceed 155% of capacity of the instru-
ment. The load may be held for any period desired provided the load does
not cycle or vary. The proof load must be conducted in a controlled area with
appropriate safety mechanisms in place. The dynamometer itself should not
provide the load reference during the test.
Original shackle pins should not be proof loaded on the 15,000-lb, 20,000-lb
and 10000-kg Model AP dynamometers with the standard anchor shackle.
The bearings can apply impressions to the shackle pins that can negatively
affect performance. Substitute shackle pins should be used in proof loading
to eliminate potential for distorting these pins. Shackle pins that require
testing should be proof loaded independently in a fixture with smooth contact
surfaces.
The dynamometers will not experience mechanical damage under a 150%
proof load, however the calibration and zero reference point may be altered.
Recalibration will restore the original performance.
Defect Removal
Allowances for
Pressure Bars
After grinding, apply suitable
corrosion protection to the
pressure bars.
Proof Loading
