Re: Losses Due To Under Utilisation Of Conveyor Capacity
Dear Shri Rekhawar,
When material being handled is of less density, the motor will be under-loaded and will be operating with high inductive component and less power factor. In this situation :
- Power consumed by mechanical machinery does not contribute to power wastage / loss.
- Power loss will only be due to comparatively more magnitude of motor idle power and power losses in power supply lines due to more magnitude of current, compared to power consumed.
Above demands the analysis of power loss and its cost versus electrical accessories cost to correct the situation.
In general, one will find that inclusion of additional items / features would not give any economical advantage.
If one wants to have equal and optimum power loading, on a motor all the time, then one has to design the conveyor such that capacity mtph by conveyor is same whether the material is of less density or higher density. This means the belt will appear partially loaded when it is conveying high-density material. The equal value of mtph is to b e achieved from control of the feeders.
Another option could be to use two-speed motor i.e. higher speed when handling light material and less speed when handling heavier material. You can discuss this with your electrical department whether the two-speed motor will have optimum loading in this situation or not.
In case, the conveyor is having more number of drives, one can also analyze whether to disconnect one or more number of drives during low load situation. The arrangement of disconnection should be part of the conveyor design.
If one wants to eliminate power losses due to poor power factor, then one can incorporate condenser / power factor correction accessories. Then, one has to live with marginally higher idle power losses in the motor only.
If the conveyor happens to be with very large with power rating in mega-watts then that case is to be analysed as a specific case to find the economically viable arrangement, if any.
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 ■
Re: Losses Due To Under Utilisation Of Conveyor Capacity
Your problem is not uncommon.
Apply a variable frequency drive (often called a VFD or AC inverter) that can span the speed range by altering the motors AC commutating frequency which is proportional to belt speed.
You get the further advantage of power savings when you don't need the added speed and tonnage.
Take care that you transfer chute can handle the change in belt speed.
Lawrence Nordell
www.conveyor-dynamics.com ■
Re: Losses Due To Under Utilisation Of Conveyor Capacity
By the By
The AC inverter will also capture energy bill savings by improving the power factor losses when running at lighter loads by altering the speed.
LKN ■
Losses Due To Under-Utilisation Of Conveyor Capacity
Dear all,
Recently, a US supplier has approached us on the subject issue. They have a product called "Motor Controller", which controls the power consumption dynamically, I do not understand beyond that.
The convetional Capacitor bank will be suiable for only one load, while the conveyor may many situation lo\ike, - No load, under load, lighter cargo etc.
We are in the process of arranging a Demo of the equipment?
Has anybody tried any such equipment in there conveyors? Please share your experience.
Regards ■
Losses due to under utilisation of conveyor Capacity
When we use common conveyor for heavy cargo like Iron Ore/Pellets and lighter cargo like - Coke, the conveyor remains under utilised, when we handle lighter cargo. This is more prominent in longer Conveyors with motor power of approx. 250 kW and above.
There are associated Electrical losses such as poor power factor, because of Drive Motor being under utilised to it's rated capacity.
Please let me know, what are the ways, by which we can reduce these losses?
Regards ■