Dear Sir,

Formulae for Horsepower are available from NIBA, CEMA, RMA, and ISO. Once you have the Horsepower requirement, it is a simple calculation to develop torque requirements.

If you do not haved access to any of these sources, you may contact me via e-mail for the formulae set.

Regards, ■

There are many books that fully cover your subject. Some are advertised on the internet as software ranging in cost from $50 USD and up. The technique is covered in this forum from books, standards, and authors such as : CEMA 1-5th editions, belt manufacturers manuals such as Goodyear, Contitech, Bridgestone, Standards such as Din 22101 or ISO 5048 and a single author's book by I. G. Mulani. ■

Dodge offers a simple program for designing small belt conveyors on their PT Wizard cd. The program will give you the HP and then you can calculate the torque as Dave suggests. The program is quite limited and is geared to Dodge products of course. But for short and simple conveyors it is a very nice program. Here's a link so you can check it out for yourself.

http://www.dodge-pt.com/ptwizard/ptwizard.html

There is also another very simple program that will calculate toque for you after you give it all the input data. "Engineering Power Tools" has a section on belt conveyors but again is very limited for conveyors. But it is a free download and it is also loaded with other very useful programs and information.

http://www.pwr-tools.com/

Good Luck

Gary Blenkhorn ■

Hello Simhup..

If I ever need to calculate approximate conveyor power, for example on simple in-plant inclined conveyors, I often do the following simple calculation.

Power = t/h x lift x 2.72 x 1.3 kW

From this you can easily calculate the torque, if you have the speed and pulley diameter from the following:

Torque = 9.55 x power divided by pulley rpm kN-m

When I was young and bright I could do the power one in my head by simlifying it to:

Power = t/h x lift x 3.5

Nice to use as a guide, especially if you don't have a calculator or even a pencil and paper on you. (Only works for inclined ones though)

Good luck

LSL Tekpro ■

Dear Simhup,

In case you wish to make approximate calculation for driving torque for the belt conveyor, you can refer to your national standard on belt conveyor or DIN or ISO, etc. This will enable you to get approximate value. The result will be approximate because the inputs you will be putting in to the formulae will be approximate in view of inadequate understanding.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

Good Job Graham,

I would add and correct your metric formulae:

Power (kW) = capacity (t/h) x lift (m) x 3.75 (not 3.5) /1000

The 3.75 includes a factor for drive efficiency (0.95) and some other small add-on factors for rolling drag and then divided by 1000 to get the units right. I checked it with BELTSTAT. It is close at > 10% slope.

Maybe, for really rough go, we could say 4.00 instead of 3.75 for those over 60. Then we get:

Power (kW) = capacity (t/h) x lift (m) x (4/1000) or .004

I hope I can remember this. Maybe give I'll do the tatoo up my sleeve. A birth mark from Graham. ■

Thank you Larry..

Now that I am over 60, I think I will also use a factor of 4 as you suggest...

LSL Tekpro ■

Originally Posted by Graham Spriggs

Hello Simhup..

If I ever need to calculate approximate conveyor power, for example on simple in-plant inclined conveyors, I often do the following simple calculation.

Power = t/h x lift x 2.72 x 1.3 kW

From this you can easily calculate the torque, if you have the speed and pulley diameter from the following:

Torque = 9.55 x power divided by pulley rpm kN-m

When I was young and bright I could do the power one in my head by simlifying it to:

Power = t/h x lift x 3.5

Nice to use as a guide, especially if you don't have a calculator or even a pencil and paper on you. (Only works for inclined ones though)

Good luck

LSL Tekpro

Dear friend,

Don't you have to consider the inertia of the rollers and initial loading?

Does anyone know how to consider the roller inertia for the calculation?

Asela ■

The established publications for calculating the power requirements of belt conveyors have been listed earlier. Suggest you get one of these and work through the examples ■

Hello Abollegala..

My quick formula to calculate the power for a simple conveyor is ideal to give you a quick indication of the power requirements.

The 1.3 factor is a variable depending on the profile of the conveyor, but after you have designed about 1000 conveyors, it comes naturally. (Unless of course, you have had a very sheltered life like my friend Larry Nordell)...

Cheers

LSL Tekpro ■

Dear Graham,

I incorrectly thought you were in retirement. Still, its nice to have your friendship and to be sheltered.

On a technical note: what do you think about my new coefficient for Overland Conveyors?

OLC coefficient = kW/Ton/killometer ranging from 0.06 to 0.10 (without lift factor)

Typical = 0.100 (pretty simple). no speed factor, et al.

Therefore kW = km x tons x (.1) + lift power

Try it you might like it.

About roll inertia - No. It has no influence. About initial loading -Yes. This can have a big influence depending on conveyor length. I recently did a presentation on this subject in Australia, Prof. Roberts 80th birthday. Results of this study tend to indicate this is a major source of energy loss unless you resort to curved hood and spoon chute geometries. ■

Indeed Larry...

I am still around, and am actually 65 years old today!

This means that from now on I will breeze in and out of retirement, roughly at the same rate as I fade in and out of consciousness, as I am now officially a member of the old fart's club.

Like the quick overland rule of thumb calc... I will pop back into my shelter and try it out and report back.

Cheers

LSL Tekpro ■

Originally Posted by Graham Spriggs

Hello Simhup..

If I ever need to calculate approximate conveyor power, for example on simple in-plant inclined conveyors, I often do the following simple calculation.

Power = t/h x lift x 2.72 x 1.3 kW

From this you can easily calculate the torque, if you have the speed and pulley diameter from the following:

Torque = 9.55 x power divided by pulley rpm kN-m

When I was young and bright I could do the power one in my head by simlifying it to:

Power = t/h x lift x 3.5

Nice to use as a guide, especially if you don't have a calculator or even a pencil and paper on you. (Only works for inclined ones though)

Good luck

LSL Tekpro

Dear friend,

don't you have to add the effect of the inertia of the rollers and the belt and materials in case the conveyor is loaded at the start..

Asela ■

No...

It's in the 1.3 factor

LSL Tekpro ■