Dear Mr. R Jones,

When you provide two numbers of drive units on a conveyor, it becomes a case of belt conveyor with multiple drives. The only difference is that this conveyor is operating in reversible direction as compared to single direction multiple drive conveyor.

The advantage of putting both end drive in reversible conveyor is that the belt tension in return run will remain fairly constant whether the conveyor is running in one direction or the other direction. So, if you have got a gravity take-up, the required belt tension will be much less compared to drive at one end. So, it gives economical conveyor. In case of stockyard reversible conveyor, the practice is to provide 2/3rd power at each end. In your case, 57.5% power at each end could be adequate (15% margin).

In case of single conveyor with multiple drives, you can adjust the power sharing precisely by adjustment in fluid coupling (level etc) or by specific feature in electrical system. However, in case of reversible conveyor the situation reverses and hence incorporating the specific setting is somewhat difficult (not impossible). So, it is better / practical to keep the contingency in power as above. So long as the power at each end does not exceed the motor rating, it is acceptable. In fact, while designing such conveyor, it is considered that one end is taking more power by certain percentage and other end is taking less and components like pulleys, take-up etc are designed accordingly.

The power sharing at each end will be according to torque speed characteristics of each drive, the length of belt passing per second at each end and consequent actual operational speed of each drive and sharing of power accordingly.

Regards,

Ishwar G Mulani.

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

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

Dear Mr Jones

The simple answer to your question is no you do not have to put a drive at both ends

It has been done before of course, and I have even seen one 400m conveyor with drives at each end fitted with worm boxes.

One drive drives one way and the other the other way.

This means that the non-drive is always being over-driven.

I did not think this possible with worm boxes but it worked with 20:1 ratio over-driven though the worm!

On a 165m long conveyor there is really no need to run two drives simultaneously

Just have one reversible drive and either a T1 counterweight or a winch

LSL Tekpro ■

Dear Mr.Jones,

We installed one yard conveyor of revesible type of 350 m in length.This conveyor is having drive in one side.Only you have to be carefull in take-up arrangement. It is in very old steel plant.At very good old days we are using one drive for reversible conveyor.

Regards.

A.Banerjee ■