Hi Shane,

You can get the T1, T2, and other conveyor related formulae from belt suppliers or trade organizations (such as NIBA, RMA, CEMA, or like organizations in whatever country you are in).

As these are standardized calculations, there is not a "best" - they are what they are. Having stated this, the use of the values obtained can differ from one conveyor designer to another. If yoyr purpose is to maximize conveyor efficiency, you should look at some of the better design and analysis methods, such as those offered Larry Nordell's company.

If you have trouble getting information on basic calculation methods, send me an e-mail, and I will e-mail the information to you when I get back to my office (10-14 days).

Regards, ■

Dear Mr.Shane,

CEMA will not give you reliable result for short conveyor( such as 20m/30m)& also for long conveyor, it is very cumbersome.In my openion it is better to follow ISO-5048 or IS- 11592.Both are similar & very simple .

Regards.

A.Banerjee ■

Morning Shane..

First very basic step is to use ISO 5048 to determine T1 and T2 for the running condition.

You have by now only scratched the surface though, especially for overland conveyors.

Next step is to add to the T2 for start up conditions.

Next step is to check there is sufficient T2 to ensure there is nowhere in the belt that the belt sag is greater than 2%.

Next step is to do dynamic calculations for all relevant loading conditions to see if the belt sag is greater than 2% during coasting.

Next step is to do dynamic calculations for any braking condition to ensure there is sufficient T2 tension to accommodate the braking force

Depending upon the position of the counterweight, the next step is to do dynamic calculations for changes in T2 during starting. If a winch is fitted then the T2 pre-tension must be calculated based on winch reaction time in conjunction with the rate at which break-away torque is applied.

Next step is to calculate T2 and counterweight configuration based on the aborted start condition to ensure that the inherent strain energy in the belt at time of abort, is not sufficient to raise the counterweight to the top of the tower, and cause slack in the belt that can propagate transient waves.

etc...etc... (Thank heavens I developed that compurter model!)

All the above and more is covered in my paper entitled "The Golden Rules" which with any luck will be presented again in August at International Beltcon 13 here in Johannesburg.

Regards to you Shane

LSL Tekpro ■

A Banerjee,

In defense of CEMA - this power calculation methodology has been used successfully to design thousands of sound conveyors over the past 50 years.

That said, the methodology was put together back in the 1950's before computers were widely available. This is the reason for all the lookup tables and simplistic calculation methods. We all know that the overall friction calculation can be too conservative, especially on long well designed overland conveyors.

Everyone should be aware that CEMA has just completed a total revision of their power calculation methodology that breaks Ky into several calculable sub factors including rubber indentation. This new manual (6th Edition) will be available in the next couple of months from http://www.cemanet.org/ ■

Hello Bud

Tell Mark I said hi.

Glad to see the plug for CEMA. I too am a strong believer in their calculations (maybe it has something to do with my copy of Analyst II)

I had read somewhere that CEMA was coming out with this latest edition on a CD. Do you know if that is still a go or not?

Regards,

Gary Blenkhorn ■