Charge conveyor

(not verified)
Posted in: , on 24. May. 2007 - 09:32

Dear Sirs,

Q=2000 t/h for ore 1400 belt width.

V=2.25 m/s

H= 56.3 meters

L=262 meters

P=3X200 total power 600 Kw. Primary driven pulley has been generated 2x200 Kw and secondary driven pulley 1x200 and 1x200 is spare. All motors have a brake and drive unit.

Their wrap angle are 200 and 180 respectivelly.

Sometimes I am confused and I need someone to confirm my decisions about the charge conveyor works with dual drive. I have no experience in this subject. I have calculated and designed all things according to CEMA.

For example, I have calculated and selected wrap angle from CEMA. The wrap angle is different on other books. For instance, Can we selected wrap angle below the 180 degrees. Because all aplications I have seen is above the 180 degrees.

For example, I have calculated and selected backstop from CEMA formulation. I have installed it on the head pulley which is non driven. For example I found the backstop torque from CEMA is 120.000 lbs-feet. But the formula on the others bock give me the 190.000 lbs-feet. torque value. Which formula gives the correct selection? I could'nt know.

General layout of the conveyor is attached.

Can some body guide me about the confirmations.

Best regards,


conveyor general arrangement (PDF)

Re: Charge Conveyor

Posted on 24. May. 2007 - 08:21

Why are you designing the system and then asking the question: did I do it right?

The forum participants are here to assist in giving insight to the unknown, in sharing advancements in design practices, in warning of safety issues, in discussing the details of installations that aid others in how good and bad engineering is discovered.

Many can see that you do not understand basic principles of design. Answering your question makes the respondant somewhat responsible for telling a story that may lead to a flawed design. Why dont you hire a competent engineer?

This forum should not be used to seek free engineering services!

Lawrence Nordell Conveyor Dynamics, Inc. website, email & phone contacts: phone: USA 360-671-2200 fax: USA 360-671-8450
Lyle Brown
(not verified)

Re: Charge Conveyor

Posted on 24. May. 2007 - 08:29

A quick way could be to consider the burden on the belt attempting to make it run away (neglecting friction etc) i.e. F=m*a (where m = mass flow rate of material / belt speed multiplied by vertical height * 9.81).

You can convert it into torque T=F*r (where is the radius is the effective “radius” between the force and where ever you are trying to measure the torque at).

This is unfactored and makes no allowance for dynamics, allowance for blocked chute burden which when half way up the belt may increase the run potential etc.

You may need to consider abnormal motor conditions also (what about if the belt is stuck – possibly from a blocked chute etc and the prime mover supplies more than characteristic running torque which if the holdback is not strong enough to withstand may result in a broken holdback).

There are other considerations and methods.



Re: Charge Conveyor

Posted on 24. May. 2007 - 09:39

Originally posted by nordell

Why dont you hire a competent engineer?

This forum should not be used to seek free engineering services!

Now there's a couple of comments that need repeating time and time again in this forum

Re: Charge Conveyor

Posted on 27. May. 2007 - 05:44

Dear Mr. Memen,

You are designing 2000 mtph conveyor with nearly 600 kW of power. If you are designing such conveyor as a buyer to make the preliminary assessment about the likely arrangement, then it may be OK, because finally your supplier is to make actual design and he will take care of the right design considering his guarantee / warrant liabilities. However, if you are designing this as an OEM, then it is advisable that you take assistance from the experts of your choice / place.

Referring to your specific query about the belt wrap angle, you can have a drive pulley with wrap angle even less than 180 degree. For example, dual pulley drive used at head end will have nearly 170 degree wrap angle for primary drive pulley and about 210 degree wrap angle for secondary drive pulley. Having fixed the stage-1 belt tension, then you have to check that at each of the drive pulley the ratio of tight side tension to slack side tension, is less than the permitted value as per the well known formula “e raised to mu x theta”. However, this is only a very small part of the total design exercise. For successful operation of the conveyor you have to check the belt tensions at least for empty conveyor, 50% loaded conveyor, 100% loaded conveyor, steady running state in each case, starting state in each case and braking state in each of the cases. In all these situations, the conveyor should perform satisfactorily ensuring no slip between drive pulleys and no where tension falling below the permitted value considering the sag limitations. In addition, professional designer also tries to make the final design economical that means the process might get repeated once or twice by changing the proportion, location of the drive etc.


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 :

Tel.: 0091 (0)20 25871916