Calculating Power required to drive a conveyor 1

[CTYLER]

Hi I'm looking for a calculation to work out the power required to move a conveyor. I have all sorts of information on the conveyor if anyone can help. The basics are its a Coal conveyor of 930 Metres long with 1.6M wide running at 3.14 m/min

Looking at putting a Motor, Gearbox & Inverter on it.

 

[desertfox]

hi CTYLER

Think we need more information like how much load its got to shift so if you now the load and say the inertia of the conveyor roller we might be able to help more

desertfox

 

[CTYLER]

Hi desertfox

The conveyor is a coal conveyor as specified and need to transport coal at a rate of 3000 Tonnes/Hour, coal has volume of 0.96 Tonnes per cubic metre. The conveyor belt weighs 88tonnes itself. It takes 5 tonnes to turn the conveyor when empty, i used a lifting block n tackle. Anything else ???

 

[desertfox]

CTYLER

If the conveyor is full how much does it take to turn it?

desertfox

 

[tygerdawg]

Option 1: websearch & download "Smart Motion Cheat Sheet" PDF that has all the dynamics formulas, calculate yourself.

Option 2: Go to the larger gearmotor manufacturer's sites and download their catalogs/engineering manuals. These documents usually provide the step-by-step instructions on how to do this.

Some (in particular the US SEW-Eurodrive site) have spiffy online calculators that you just plug & chug, out spits an answer in the form of a gearmotor model (with input motor power & output torque/speed).

SEW-Eurodrive, Nord, Falk, Dodge, others....it's all the same, just some more sophisticated analysis than others.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[CTYLER]

We dont know how much it take to turn when full.
Ive attached a Word document with a schematic and brief description.

 

[desertfox]

hi CTYLER

From your 3000Tonnes per hour and a given length of conveyor belt you can work out the power required to shift that amount from :-

(3000/3600)*2m * 9.81 = 16.35kw

I have assumed the 2m is conveyor length, as a length is not given, you then need to add the power to turn the conveyor and gearbox at correct speeds which will of course be dictated by the conveyor roller diameter.
In addition you will need the rotational inertia of the gearbox, conveyor rollers and coupling plus an allowance for friction and efficiency of the system.
Once you have all that you then need to consider when the motor is starting up, how fast you want it to come up to full speed as that will have a bearing on motor power and size.
The inertia's and friction at start up plus the power to move the load will determine how much torque the motor needs to have and its susquent power rating.
Finally I would talk to a motor/gearbox manufacturer because if there is frequent stopping and starting of the motor then again that will have a bearing on motor size and power.
I am no expert in this field but its not just a simple calculation you can determine in a few minutes from a single formula.
Thats the best I can suggest from the information you have provided.

Regards

desertfox

 

[desertfox]

hi CTYLER

My apologies you did give conveyor length in your original post, I missed that as I was looking at the sketch you uploaded.
However it doesn't help me give you any further information.

desertfox

 

[FeX32]

16.35kw ?
Sorry but that doesn't make sense to me.
OP- You would need more specific information to approximate a prime mover power.

Fe

 

[desertfox]

Hi Fex32

Yes your right, I was thinking of moving a mass over a distance but that would only makes sense if it moves vertically, of course in moving the mass horizontally you only need to overcome the friction it generates on the conveyor rollers.
CTYLER please ignore my 16.35kw it is wrong.

Thanks FeX32

desertfox

 

[PeterCharles]

You should get yourself a copy of the CEMA publication "BELT CONVEYORS FOR BULK MATERIALS". Conveyors of this size are not for the faint hearted!

http://www.cemanet.org/publications/index.html

Look also for a specialised bulk materials handling forum for assistance.

Rough calculation maybe around 400 - 500 kW with a horizontal machine.

 

[FeX32]

No problem desertfox.
Although, I do agree with the other comments you made on 8 Apr 09 12:09.
The OP needs to be more specific if he wants a specific answer.



Fe

 

[CTYLER]

Hi All thanks for your responses
What other information is required & i will try provide it.
I did speak with a conveyor manufacturer and he told me for a new conveyor on my specification length, rate, speed, width conveyor, incline & volume of 0.96 T/metre3. He told me it would be 400kW.

Carl

 

[desertfox]

Hi CTYLER

We need most of the information I mentioned in my earlier post i.e. - gearbox, conveyor roller and coupling inertia, gearbox ratio and output speed and power, conveyor roller diameter etc.
Basically whatever you have given to the conveyor manufacturer in order for him to tell you a 400kw motor is required.
If you have already been advised on a motor size why are you trying to size it, is it just a check or do you think you’re being sold a bigger motor than you need.
In your last post you also mention an incline so presumably the coal is lifted slightly which would also increase the motor power output.
Your uploaded file shows existing motors of 340kw so what modifications are you doing to the system?
In a nutshell if your trying to size a motor you start at the conveyor and work backward accounting for the different loads, gearboxes, couplings etc then you have too allow for efficiencies and friction as well as deciding how quickly you want the system up to full speed, this last requirement alone will have a massive affect on motor size.

desertfox

 

[CTYLER]

The system currently runs fine but was built in 1972 and we are having problems with Fluidrive's failing, costing nearly 8k each time. Motors & Gearboxes are very inefficient we have measured the currents being currently pulled and the primary only pulls 40 amps and motor full load is 75 amps so in a nutshell we would like to be able to fit new motors and gearboxes but downrate them so we are running the motors at full load i.e full efficiency.
The exisitng G/box is a hansen unit which is has ratio of 24.5:1 ,output power of 298kW - input speed of motor is 1470 rpm and 345kW, but we know the motor is only dragging 182kW.
Some Additional Info
Weight of Belt 88 T
Weight of Primary Drum 4 T
Weight of Secondary Drum 3 T
Diameter of Head Drum 1250 mm
Diameter of Drive Drum 1000 mm
Diameter of Tail Drum 800 mm
Head to Tail Centres 930.35 M
TotalLength of Conv. 1936 M
Gravity Weight 16 T
Type of Belt ST1600 1.6M wide
Head to Tail Incline 5 M
No. of Idlers 3 per 900 mm
Weight to Move Conveyor 5 Tonne Pull will move conveyor when empty

Volume per Cubic Metre 0.96 T

From the 182kW the motor pulls when fully loaded im thinking that with new energy efficent Motors & G/boxes & fitting an inverter im looking to downgrade to 250 kW if not a bit lower.

 

[desertfox]

Hi CTYLER

Thanks for the quick response, a quick calculation shows about 57% efficiency if I divide running current by full load current.
However how often is the motor started and stopped? also what power is needed to get the system up and running from standstill.
Why don't you put your considerations to a conveyor manufacturer and tell them you want to get the efficiency up if possible.
Have you spoken to the fluid coupling people about the failures?

desertfox

 

[CTYLER]

Thanks for your quick response i really appreciate all this advice. I have put forward all my informationa dn they are saying they wouldnt comment on the existing system and would only quote as if they were building a new one. The people who made the fluidrive no longer exist and the people who are overhauling them are basically saying that they are knackered and mostly beyond economical repair but at present we need them. The conveyor is probably started one day then runs constantly for about 3-4 days then will probably stand for a day or so so the stopping and start is infrequent. The conveyor at present is direct online and looks to pull about 100 amps for a few seconds, but if we werre to fit a drive we could ramp up slowly.

Carl

 

[desertfox]

Hi CTYLER

Well control and inverters are well outside my field, it seems that the conveyor people aren't interested in upgrading your existing system did the do the original system?
One last thought why don't you approach a motor/gearbox manufacturer and invite them to look at your system I am sure they must have experience of these sort of drives, if your in the uk then why not give SEW motors a call.

http://www.sew-eurodrive.co.uk/

Also they can perhaps advise better on the drive coupling.
I have used these people in the past and found them helpful.
It appears from your post that you don't want to replace the conveyor but just the drive system so I would ditch the conveyor people and contact motor drive and control companies.
In the meantime I'll look at the information you have provided.

regards

desertfox

 

[CTYLER]

Thanks Matey help much appreciated. Control & Inverters are my area so happy with them just never had to work out power like this before. Will give SEW a call.

Carl

 

[desertfox]

hi CTYLER

Your welcome.

desertfox