Dear Khalid

I will suggest forth alternative

provide Dual drive near head end with tail pulley as take up.

you provide 2 nos of 200 kw LT ve without fluid coupling with vvfd

Nowadays VV FD Drives are much economical and you can cotrol better accelaration and stoping of conveyor. you canalso syncronise RPM and load sharing of both drives.

With this arrangement you can use lt motors, avoid fluid couplings, have take up at tail end , with dual drive belt rating can be reduced.

Mr khalid so many combinations are feasible it is indivisual choice based on his judgement

A R SINGH ■

Dear Sirs:

Individual choice? What happened to good engineering practice and appropriate knowledge to suit the application?

I would bet a years salary, your design will cost the client unnecessary capital and operating expenses that far exceed you expectations.

So where does that leave your question and the answer that followed. THere is an old arab proverb about -- " not knowing that you don't know".

I further find it a misuse of the forum to beg for engineering consultancy. This forum is intended to inform on problems, not ask for free services. ■

Dear Mr. Khalid,

I appreciate that you have put your question very nicely and systematically. There are two methods / options to arrive at the answer to your problem.

1) If you / your company is designer and manufacturer of belt conveyor, then you have to make preliminary estimate for the cost / price of the alternatives you are referring. When you estimate for the cost, you have to consider the cost of mechanical, structural, electrical, civil, instrumentation and spare parts. If your company is engaged in this profession the concerned people will quickly have the answer as to which one is the most economical.

2) If you are buyer of such system, then in your enquiry specifications, you can just mention that bidder should quote for the concerned alternatives. Then, you can choose the one, which is the most economical in totality.

One has to also see the convenience of operation and maintenance in the both the cases (serial no. 1 and 2).

Above is the rational approach to arrive at the decision. In your case, conveyor length is not very long. It is just 1.2 km. If the conveyor is having sufficient lift, then you may find dual pulley drive at the head end is economical in above analysis. If the conveyor is not having sufficient lift, then the larger drive at head-end & comparatively smaller drive at tail-end could be economical from mechanical point of view, but it will add complexities into proper functioning of both the drives. Many times, OEMs as well as user prefer least number of drives to the extent feasible. More number of drives means multiplicity of maintenance.

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 Khalid

The most important aspect of your conveyor is the profile.

If you intend to put as much power onto such a relatively short conveyor at such a low capacity, then obviously there is considerable lift, (like 40m of it). If ths is the case, then I am a bit surprised that you did not mention it

If this is the case, the positioning of the cownterweight, and vertical radii are dictated by the starting and stopping dynamics of the conveyor

If you cannot do such calculations, then as Larry implies..get someone who can to do it.

Such a conveyor is typical of why I spend at least 55% of my time fixing the arrangements of exisitng conveyors all over the world, and why we are to present a paper on it at the International Materials Handling Conference Beltcon 13 this year.

Regards

LSL Tekpro ■

Dear Mr Khalid

The most important aspect of your conveyor is the profile.

If you intend to put as much power onto such a relatively short conveyor at such a low capacity, then obviously there is considerable lift, (like 40m of it). If ths is the case, then I am a bit surprised that you did not mention it

If this is the case, the positioning of the cownterweight, and vertical radii are dictated by the starting and stopping dynamics of the conveyor

If you cannot do such calculations, then as Larry implies..get someone who can to do it.

Such a conveyor is typical of why I spend at least 55% of my time fixing the arrangements of exisitng conveyors all over the world, and why we are to present a paper on it at the International Materials Handling Conference Beltcon 13 this year.

Regards

LSL Tekpro ■

Dear Khalid,

For your project you can use 1 no. 400 kW HT drive which I feel be more economical, because you need not to step down your existing power supply (which I feel 6.6 kV presently) and you need not to change your motor. However if you provide all your existing system then I can give you more precise solution.

Regards,

Sudip ■

Dear Mr. Khalid,

In my earlier reply, I missed one point.

In general, one would rarely find single conveyor in a plant. The belt conveyors are always in a group. Having done a design for all such belt conveyors, the next very important step is standardization of various items in belt conveyors, like pulleys, bearings, drive motor, gear boxes, couplings, etc. The standardization, always increases the immediate cost of the equipment proper, but it also simultaneously tends to reduce the procurement rates, spare parts cost, maintenance and upkeep cost, etc. So, the provision of single or multiple drive is also affected by the standardization of the item i.e. finally chosen different motor sizes to be used in plant etc.

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 ■

Hi Rekhawar..

It is very simple to limit the torque of an electrical VSD in the PLC.

It is also simple to put a torque limiting HS coupling between the motor and the gearbox. This works well in conjunction with a belt underspeed switch, as well as a being must for drives fitted with flywheels.

Try and stick to simple TSS type fluid couplings for your average conveyor though, unless your start times are greater than 45 seconds or so.

LSL Tekpro ■