Cooper Instruments & Systems WTM 502 Wire Tension Meter - Manual (Page 12)

Exception: Sheaves match the wire diameter of the cable to be measured and alternate calibration is
selected as per section 5.2.
Insure that the wire rope is riding in the groove of all three sheaves.
Do not use the WTM 502 with cable larger than indicated on the sheaves. Overload and damage to the
instrument may result.
Do not mix sheave sizes. This will result in inaccurate measurement and possible overload.
FIGURE 7 CHANGING SHEAVES
5.0 ACHIEVING BEST ACCURACY
5.1 Accuracy
The WTM 502 is an instrument designed to give accuracy that typically exceeds normal requirements for
wire tensioning. You should have an understanding of what factors affect tension measurement accuracy.
5.2 Calibration to Specific Wire Type
While it is best to have the instrument calibrated to the specific wire size(s) and type(s) used, the WTM
502 can often work adequately in other situations. If the best tension accuracy is required, Cooper
recommends that a calibration be performed for that specific wire size and type.
What calibration choice and sheaves should I use?
Situation
Wire calibration
selection
Sheave
selection
Accuracy
Exact wire size and type is
shown in wire list
Description of exact
match
Sheaves noted in list Best
Wire size is same, but type is
not identical
Description of same wire
diameter
Sheaves noted for that wire size Good
Wire size is not the same Closest diameter
Sheaves matching the wire size
being measured
Fair
Contact Cooper Instruments for any additional calibrations you may need.
Do not use the WTM 502 to measure tension for wires if both of the following are true:
CF 142 10 V 08/09/05