Version 1.0
Drive Pro
Start Screen
Drive Pro
Start Screen
Drive Name: This identification will carry
through the analysis and printout. Any
combination of characters may be used.
The field can be left blank.
Drive Pro
Start Screen
No. of Pulleys: Input the total number of
pulleys in the drive, including idler pulleys.
Drive Pro
Start Screen
Belt Type: Click on the drop-down box to
select a belt type. This will enable the Belt
Cross-Section selection box.
Drive Pro
Start Screen
Belt Cross-Section: Click on the drop-down
box to select a belt cross-section. A belt type
must be selected before this box is enabled for
selection.
Drive Pro
Start Screen
Select System of Dimensions: Select either
Inch-Pound or Metric units. All dimensional data
in input fields and output fields will be based on
this selection. Inch-Pound and Metric units
cannot be intermixed in this program.
Drive Pro
Geometry Options Screen
Drive Pro
Geometry Options Screen
A tensioning option must be selected
to proceed from this screen.
Drive Pro
Geometry Options Screen
No Idler – Locked Center
Use this option for drives which are
statically tensioned.
Drive Pro
Geometry Options Screen
Moveable Idler - This option can be used on
drives with pivoted idlers or slotted idlers. Idler
coordinates are input at the nominal position
and all calculations are based on this position.
No details of the idler path are required.
Drive Pro
Geometry Options Screen
Pivoted Idler
Use this option to get a complete analysis of idler
path for a pivoted idler. Idler arm length and
pivot point are required on the next screen.
Drive Pro
Geometry Options Screen
If Moveable Idler or Pivoted Idler options are
selected the Idler Pulley No. box will appear.
The number of the idler is required. To determine
the idler number start with the driver pulley as
Number 1 and proceed around the drive opposite
to belt direction.
Drive Pro
Drive Analysis Output Screen
Drive Pro
Drive Analysis Output Screen
Parameters are shown for each load condition.
Note that hovering over Slip Factor and
Effective Pull labels will show the maximum
recommended values for these parameters.
Drive Pro
Drive Analysis Output Screen
• Our philosophy in creating this program was
to provide a tool that would assist in good drive
design.
• Reliable and consistent belt performance
depends upon the design of the drive itself.
• We’ve tried to provide as much information
about the feasibility of the drive as possible.
Drive Pro
Drive Analysis Output Screen
• Various cautions and warnings will appear
when appropriate to help the user recognize
potential problems.
Drive Pro
Drive Analysis Output Screen
• The most eye-catching part of the output is
the calculated life.
Drive Pro
Drive Analysis Output Screen
• Note that we have expressed life in “flex
units” rather than in hours or cycles. This term
is a reminder that this is a number that
requires interpretation.
• The parameters that go into the life
calculation are based on controlled laboratory
tests. The number of flex units approximate
average hours of life with the same drive on a
controlled lab test.
Drive Pro
Drive Analysis Output Screen
• However, actual field conditions are so varied
that this does not necessarily translate directly
to hours of belt life at field conditions.
• For example, a mower blade drive may have
the same geometry and loading as the lab test,
but the drive must operate under a variety of
conditions detrimental to belt life. These
include various degrees of misalignment, shock
loads, clutching, dust and grit, and higher
temperatures. All of these parameters reduce
belt life but cannot be clearly accounted for in
a drive analysis.
Drive Pro
Drive Analysis Output Screen
• A practical way of using flex units is to
compare the new drive to one that you already
have experience with.
• For example, if you are designing a mower
blade drive, compare the flex units of the new
drive to a successful existing blade drive.
Drive Pro
Drive Analysis Output Screen
• When trying to determine which pulley or
load condition is doing the most damage to the
belt life look at the “Life / Pulley” numbers.
• The pulley with the lowest life is the one that
is limiting the overall life of the drive.
• The pulley diameter and the belt tension over
that pulley are the major factors that contribute
to the life calculation.
• Simply increasing the diameter of the pulley
will increase the belt life. This is especially true
for backside idlers.
Drive Pro
Effective Diameter Help Screen
Drive Pro
Effective Diameter Help Screen
• Helps to quickly determine pulley effective
diameter from diameter over pins or from the pulley
groove dimensions.
• The steps required are listed on the screen.
• The program will recalculate the desired diameter
each time the Calculate button is clicked.
Drive Pro
Effective Diameter Help Screen
• A handy shortcut is to copy the calculated
effective diameter from this screen and paste it in
the appropriate field on the Drive Geometry Screen.
Drive Pro
Cautions & Warnings
• Cautions and warnings may appear as the
program is executing and will appear on output
printouts.
• Following is more detail about each warning
and how they can affect drive performance.
Drive Pro
Cautions & Warnings
EFFECTIVE DIAMETER IS BELOW
RECOMMENDED MINIMUM DIAMETER:
This warning displays the recommended
minimum effective diameters for inside and
backside pulleys for the specified cross-section.
Although calculated life may be adequate even
at this below minimum diameter, you will
achieve more consistent performance if you
increase the diameter. This is especially true
for backside pulleys. Belt construction
becomes more critical for back bending on
small pulleys.
Drive Pro
Cautions & Warnings
HIGH SLIP FACTOR (LT). EXCESSIVE SLIP IS
POSSIBLE:
The Slip Factor, which is also called LT, is the
ratio of effective pull to belt wrap and is
calculated for each pulley at each load
condition. It is a function of horsepower,
speed, pulley diameter, and drive geometry.
The warning message appears when maximum
recommended values are exceeded at a specific
load/rpm condition.
Drive Pro
Cautions & Warnings
HIGH SLIP FACTOR (LT). EXCESSIVE SLIP IS
POSSIBLE: (continued)
Although this usually occurs at the Driver
pulley, it can occur at any loaded pulley. Look
for the highest value of LT to determine the
critical pulley. LT can be reduced by reducing
horsepower, increasing speed, increasing pulley
diameter, or changing drive geometry to
increase belt wrap on the critical pulley.
Drive Pro
Cautions & Warnings
HIGH SLIP FACTOR (LT). EXCESSIVE SLIP IS
POSSIBLE: (continued)
LT is just one of many factors which are used
to evaluate the robustness of a belt drive.
Since it is derived from horsepower load data,
it is only as reliable as that data. A belt can
slip through momentary peak loads without
significant damage due to slip. However, if a
drive runs for continuous periods with high LT,
the belt life may be low and unreliable.
Drive Pro
Cautions & Warnings
HIGH EFFECTIVE PULL. ARAMID CORD
RECOMMENDED:
Effective Pull (EP) is a function of horsepower
load and belt speed. The warning message
appears when EP exceeds approximately 12
percent of the belt tensile strength with
polyester cord. EP can be reduced by reducing
horsepower, increasing speed, or increasing
driver pulley diameter (increases belt speed).
Drive Pro
Cautions & Warnings
PULLEY RIM SPEED EXCEEDS 6500
FEET/MINUTE (33 METERS/SECOND):
Cast iron should not be used as a pulley
material if rim speeds exceed 6500 fpm (33
m/s). The pulley may explode at speeds above
this. Use steel or ductile iron. Dynamic
balancing may also be desirable at these
speeds to minimize drive vibration.
Drive Pro
Cautions & Warnings
CALCULATED BELT LIFE IS LESS THAN 100 FLEXUNITS. DRIVE RELIABILITY IS VERY LOW:
This warning is a message that your drive will have
low reliability if input load data is realistic. A flex
unit is equal to one hour of life on a lab test with
the same parameters. Actual drives in the field will
usually exhibit lower life due to conditions such as
misalignment, shock loads, excessive heat, etc. It
is recommended that drives with less than 100 flex
units calculated life be reexamined to improve life.
Drive Pro
Cautions & Warnings
CALCULATED BELT LIFE IS LESS THAN 100 FLEXUNITS. DRIVE RELIABILITY IS VERY LOW: (continued)
Some of the most effective ways to improve belt
life are larger pulley diameters, reducing load (and
belt tension), or selecting a different belt crosssection. If you become locked into a low life drive,
belt construction will become critical to achieving
acceptable performance. Consult with your Carlisle
belt application engineer regarding ways to
improve this situation.
Drive Pro
Cautions & Warnings
BELT WRAP ON PULLEY IS LESS THAN 100
DEGREES:
This message appears when a loaded pulley has less
than 100 degrees of belt wrap. This situation can
mean a chronic slip problem especially if combined
with low or unreliable belt tension. If you’re stuck
with this situation on a pulley with significant
horsepower load, use the tension calculated by this
program as minimum tension. One way to judge the
significance of the load is to examine the Slip Factor
(LT); if it exceeds a value of 15 on this pulley, the
load is significant and tension will be critical to
performance.
www.CarlisleBelts.com
from
www.c-rproducts.com
sales@c-rproducts.com
Tel: +44 1327 701030
Fax: +44 1327 701031