your predicament definetely sounds like overloading -please tell me more about your boom system-it sounds as if your gear box is driving all components of the boom -if this is so it will explain why it shuts down as it is a smaller gearbox-too high an amperage etc. ■

Is the motor tripping out on overload?

Have you determined how the trip is occurring?

Is the boom raise on a seperate drive?

Is the boom raise drive tripping or the conveyor drive?

Are you 100% certain that the speeds are the same?

It certainly sounds like an overload problem as if the conveyor is running slower than before.

Describe exactly what the difference was in the ratios and what changes you made to the drive pulley diameter?

Have you done an AMP check on the motor and compared that against the FLA of the motor?

The more info you can provide the better for us to understand your problem. ■

In a word -NO- not possible unless it is past splash level of gears/ not possible. ■

Dear Mr. Kamlesh,

Gear box will not alter the conveyor capability for operation except in following situations:

1) Resulting in different belt speed for conveyor.

2) Gear box efficiency should be nearly same. This implies that, if you have say a helical gear box and if you replace it by worm gear box, then there would be more power losses in worm gear box and net available power for conveyor would become less. This would result in inability for the conveyor to operate (if motor kW rating is critical to the need).

Now, you are saying that the belt speed is same. I would suggest you to check it again. If this speed is same and gear box efficiency is also nearly same (same type of gear box), then your problem could be other item of the drive, by coincidence. Check for the proper quantity of oil in the fluid coupling, proper release of brake, handling rate mtph, etc.

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 ■

Dear Shri Kamlesh,

Further to my earlier reply, I would like to add the following.

If the replaced gearbox is too much oversize, then it would also result in to more loss of power in the gearbox and less power at the drive pulley. Also check the actual voltage at the motor terminal during starting and continuous running and find out why there is inadequate availability of power at drive pulley. One also needs to check the proper alignment of various components in a reconstructed drive. I presume you have not reduced the drive pulley diameter in the reconstructed drive as it may be harmful to the belt.

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 ■

we have solution for the aproblem u r facing if u want to solution contact on 09424972960 ■

Hi Kamlesh,



What is the status now? ■

hi,

i m manager in a cement industry i think no problem in ur gear box as its have same rating [torque, kw etc] . we r facing same problem at high luffing angle boom started slippage problem at full load and damage lagging of drum. u need to resdesign of conveyor. we have done in our factory and running sucessfully since last 10 months without change motor and gear box. if u want specialized sevice for your conveoyr. u can contact me on +919424972960 or give detail at rkkushwaha@sify.com

thaking u, ■

The boom conveyor is part of stacker, reclaimer or stacker cum reclaimer machine. The well-known manufacturers of such machines are generally competent and to have correctly designed belt conveyor should not be an issue for them. They must have sized the motor and other component of conveyor considering the maximum positive inclination and maximum negative inclination. You are mentioning that you are not able to convey material beyond certain inclination. This can have a 3 types of situations as below :

1) Motor gets tripped due to overload. Then the motor is undersized.

2) The material is not getting accelerated and conveyed. However such condition will not occur just at 6 degree inclination.

3) Motor is getting tripped due to slippage of belt, by signal from zero speed switch. In this case you have to increase the belt tension to the required value, by measured means and not by feel or judgement. This might have been mentioned in the maintenance schedule.

Please see that replaced gear box has not altered the drive pulley rpm (5% here and there does not make any difference). If the gear box is of required ratio but is undersized, then it will fail (breakdown), but it will be unable to change conveying capability till it is broken.

Ishwar G. Mulani

Author of book : Engineering Science and Application Design for Belt Conveyors

Author of book : Belt Feeder Design and Hopper Bin Silo

Tel. No. : 0091 (0)20 2587 1916

Email : parimul@pn2.vsnl.net.in ■

Originally Posted by KAMLESH

The ratios are different but i modified the drive drum to attain the same speed.

The belt does not take load above 8 degrees which it should

Belt is not slipping.....it shut downs when the boom is raised.

The following issues need clarification before the forum members can provide meaningful replies.

Are you maintaining the same drive drum axis?

Have you relocated any snub drum to restore the wrap?

Is the new drum diameter an increase or decrease?

What have you done about drum superelevation?

Have you raised or lowered idlers to meet a new belt line?

Is there perchance a torque limiting coupling somewhere?

Once we know more about what the conveyor should perform like on the flat then we might be able to determine what it could do on the luff!

If you had checked drawings, nay; even prepared drawings, the above questions should have already been answered. ■