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An optical meter directly measures belt vibration. Using advanced
solid-state infrared technology, the sensor actually “sees” the
belt surface. Any displacement of the belt is observed and the
frequency of displacement over time is measured. This method of
direct measurement is unaected by ambient conditions resulting
in superior accuracy without the need for ilters or manual tuning.
If the meter uses an infrared beam, what is the lighted spot I
see on the belt?
The orange-lighted spot is generated by a narrow angle LED (Light
Emitting Diode). It is focused to the same area as is the infrared
generator and is to be used as an aiming guide for the invisible
infrared beam.
What about operator safety? Isn’t an infrared beam really an
invisible death ray?
Don’t confuse the optical sensor with a laser. Lasers are intensiiers
that project a coherent beam (parallel rays) with low divergence
and high brightness. The result is a focused beam with very high
energy density. The sensor of the TensionRite® Belt Frequency
Meter uses the non-coherent infrared output of a small
low-energy diode.
Do I need to input span length and belt mass parameters each
time the meter is used?
Not necessarily. If you are dealing with a drive on a regular basis,
the memory feature of the TensionRite® Belt Frequency Meter may
be to your advantage. Up to three dierent sets of belt parameters
can be stored in the meter, each assigned to one of the three
MEM keys. The next time that particular drive is tensioned, pressing
the appropriate key will recall and load the belt mass and
span information.
You can also eliminate completely the need for span and mass
parameters by working directly with the belt vibration frequencies
(f) measured in hertz (Hz) rather than with belt tension values
(expressed in units of force). Hz values are independent of mass
and span values. The output of the MaximizerPro™ program gives
target Hz values in addition to traditional tension values. Armed
with the correct Hz information simply follow the steps shown in
the “Quick Start” section of the User Manual.
How do I determine span length?
There are three common methods to determine span length:
using the output from the MaximizerPro™ drive-analysis program,
performing a mathematical calculation or by direct measurement.
MaximizerPro™, a user-friendly drive analysis program, will
automatically report belt tensioning parameters (including span
length) as part of your drive selection process. Or, you can make
the calculation manually using the formula shown in the User
Manual. You must know the center distance (dimension between
shaft centers) as well as the diameter of both driveR and driveN to
complete the calculation.
The least accurate but sometimes most practical method to
determine span length is by direct measurement. Span length is
deined to be the length of the unsupported belt between the exit
point of one pulley and the entry point of the adjacent pulley.
Simply locate these two tangent points as best as you can and
then measure between them along the back of the belt. The
resulting measurement (expressed in meters) is your span length.
Our company operating procedures require periodic
calibration and certiication of measuring tools. Are there such
procedures for the TensionRite® Belt Frequency Meter?
Yes there are. The solid-state circuitry of the TensionRite® Belt
Frequency Meter is based upon a very stable quartz crystal which
requires no adjustment. Included with your meter is a precision
mechanical resonator (fancy term for a tuning fork) to allow a spot
check at a frequency of 250Hz any time you wish. See section
“Calibration” in the User Manual for a depiction of the procedure.
Labeling the meter as a “Process Aid” coupled with performance
of this spot check on a periodic basis might well satisfy your
procedural requirements. If more rigorous documentation is
required, the meter may be returned to the manufacturer at yearly
intervals to have the calibration certiied to UKAS (United Kingdom
Accreditation Standards) ISO/IEC 17025:2005. Such certiication
is generally acceptable for ISO9001. The manufacturer must
be contacted for detailed return procedure prior to sending the
meter. There will be a charge for this service. The section “Annual
Certiication” in the TensionRite® User Manual gives contact
information for the manufacturer.
Will the meter work for belt brands other than
Continental ContiTech?
Yes, the TensionRite® Belt Frequency Meter will give accurate
results for belts from other manufacturers. The frequency (Hz)
measuring mode is immediately applicable. In order to harvest
accurate tension values (in units of force rather than frequency)
you must know the belt mass constant for your actual belt.
How do I determine belt mass short of contacting
a manufacturer?
There is no secret to belt mass. It is deined as the unit weight of
the belt or the linear belt mass and is expressed in kg/m. So simply
weigh the belt on an accurate scale such as a postage scale,
convert that weight to kilograms, then divide the result by the
length of the belt expressed in meters. For example: say you have
a generic synchronous belt of part number 1280 8M 50 (8mm
pitch, 50mm wide, 1280mm long). Your postage scale says the
belt weighs 9.9 ounces. Your calculations become:
9.9 ounces x 0.02835kg per oz = 0.281kg
(conversion constant from chart)
1280mm x 0.001 = 1.28m (metric convention)
0.281kg / 1.28m = 0.2195kg/m = round to = belt mass = 0.220kg/m
This is the number to then input as belt mass.
We are being asked to comply with some new environmental
regulations called RoHS (Restrictions on Hazardous
Substances). What is the status of the TensionRite® Belt
Frequency Meter in relation to RoHS?
The manufacturer of the TensionRite® Belt Frequency Meter states
that they are in full compliance with the restricted materials listed
in the Directive 2002/95/EC of the European Parliament and the
Council of 27 January 2003, commonly referred to as RoHS.
Appendix 3.0 Frequently Asked Questions
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