Relationship between HP, RPM, and Torque

When designing a belt drive, the load being transmitted is one of the most important pieces of information that is needed.  To properly describe the load, there are two key pieces of information: HP and RPM, or Torque (Q) and RPM.  RPM is important in either case to quantify the load.  Believe it or not 10hp at 1000rpm is not a very high load compared to 10hp at 100rpm.  Here are the equations that relate one to the other:

This is for torque in in*lbs

HP = (Q x RPM) / 63025

Q = (HP x 63025) / RPM

This is for torque in ft*lbs

HP = (Q x RPM) / 5252

Q = (HP x 5252) / RPM

If we use the example above, the torque for 10hp at 1000rpm is 630.25 in*lbs, where the torque for 10hp at 100rpm is 6302.5 in*lbs, a pretty big difference for your belt drive!

Introducing Poly Chain® Carbon™ Volt ™

Belt drive applications are sometimes located in potentially explosive atmospheres requiring belts to be static conductive.  This allows naturally generated static electric charges to be dissipated into sheaves, shafts, bearings, etc. and safely to ground.  Static conductive belts are required by various industries, such as the petrochemical industry.  Until recently, static conductive synchronous belts were only available on a made-to-order basis.  PowerGrip^® GT3^® belts in 8mm and 14mm pitches are now static conductive to ISO 9563.  And Poly Chain^® Carbon™ Volt™ has just been introduced.

Poly Chain belts have never met industry standards for belt conductivity until now.  Poly Chain Carbon Volt belts utilize several patented technologies that enable excellent conductive properties that are retained much longer than any other belt available.  Industry standards for belt conductivity (ISO 9563 for synchronous belts, ISO 1813 for V-belts, ARPM IP-3-3 for all belt types) apply only to new belts.  There are no belt conductivity requirements for belts that are in service, and belt conductivity properties are known to decline over time at a fairly significant rate.  Testing has shown Poly Chain Carbon Volt conductive properties to retain much longer than conventional belts, so are considered to be much safer over time. 

Poly Chain Carbon Volt belt testing has not yet shown belt conductivity properties to fall below ISO 9563 standards, so it may not be unreasonable for conductivity to be retained throughout belt life.  Even so, grounding brushes are always recommended as a secondary means of dissipating static electric charges in belt drive systems located in potentially hazardous environments.

Poly Chain Carbon Volt belts can be made in any standard size, but are not yet available in every size.  Check with your local Gates Industrial Distributor for availability.  If you have any questions, contact Gates Product Application Engineering at ptpasupport@gates.com or 303-744-5800.

Safe Hose Selection

Proper hose selection is critical to a safe hydraulic system, hose performance characteristics and service application an easy method is used to properly select a hydraulic hose. An effective way to remember this hose selection criterion is to remember the word STAMPED. S T A M P E D S = Size T = Temperature A = Application M = Material to be Conveyed P = Pressure E = Ends or couplings D = Delivery (volume) The first step in having a safe hydraulic system is selecting components that meet your needs. Compromises in hose selection may put you in danger, as well as affect the performance and life of your system. The decision may work for the short run, but may not be a good long-term decision. Remember, the most important thing is your safety. Most hydraulic systems should be designed with a 4:1 safety factor (burst test pressure vs. maximum recommended working pressure). However, some applications may have different standards (examples: water blast, jack hose).

Standard V-belt Sheaves for Round Belts

The table below summarizes the standard V-belt sheave options for round belts.

Light Duty V-belt Sheave Size	Heavy Duty V-belt Sheave Size	Closest Fit Round Belt(s)
0	-	3/16"
1	-	5/16"
2	A	3/8, 7/16"
3	B	1/2", 9/16"
-	C	11/16", 3/4"
-	D	1-1/16"

EZ Align Battery Life

Occasionally we get questions about battery life on our EZ Align tool.  Typically it is not a problem, but not all AAA's are created equal.  For best battery life, we recommend Lithium batteries.

Calculating Pressure Drop for a Hose Assembly

With some basic system information, reliable pressure drop approximations may be readily calculated. First, determine the applicable mechanical components and fluid for the analysis. Completing this process one hose assembly at a time is recommended. Next, enter those values into the Gates online pressure drop calculator (Fluid Flow Calculator). The link to the calculator is: http://www.gates.com/catalogs-and-resources/resources/repository/engineering-business-applications/fluid-flow-calculator/fluid-flow-calculator . Required Hose Assembly information to complete the calculations includes Inside Diameter, Length, Couplings, and Adapters. Required Fluid Information includes Density, Viscosity, and Heat Capacity. These may be estimated with fluid type and temperature. Examples of Specific Gravity and Viscosity for some common fluids are: Water- Specific Gravity 1.00, Viscosity 1.0; Gasoline- Specific Gravity 0.71, Viscosity 0.5; Ethyline Glycol- Specific Gravity 1.12, Viscosity 19.5

Check Your Drive Before You Wreck Your Drive

When a drive experiences problems it's easy to assume the belt is defective, or that the standard belt construction is underrated for the application. Before blaming the belt or requesting a made-to-order belt construction, please consider the pie chart below (click to enlarge). There are many factors that can lead to premature belt failure. This chart illustrates the most common sources of drive problems. Download the Belt Drive Preventive Maintenance and Safety Manual for more information. Also, check out our failure analysis blogs for V-belt and synchronous drives to troubleshoot drive problems.