Determine Horsepower for conveyor 1

[cwsink]

Hello,

I've got a conveyor to design which I need to confirm the horsepower requirements. Following are the specs:

50" wide sliding flat belt
60" long
4" diameter drum pulleys on each end
750fpm

The weight of the product on the conveyor is negligible (cardboard box sheets). I will use a 15:1 gearbox between the conveyor and motor.

I realize there could be more info given, but I don't have it either! Hopefully someone with experience could give me a general idea what kind of power requirements this thing would have.

Thank you for any guidance,

Craig Sink
FDI, Inc.

Craig Sink
Mechanical Engineer
Force Design, Inc.

 

[MintJulep]

Five feet long and 750 fpm?

 

[GregLocock]

whoosh!

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[zekeman]

Going horizontal,only friction and sartup torque.
I would sal that 1/4 HP would easily do it.

 

[cwsink]

Yes, 5 feet and 750fpm is the target velocity. Its an addition to a current system that is only running at 450fpm now, but they want to be able to bump it up to 750fpm eventually.

1/4hp is quite a bit less than what I was thinking, but thanks for the input. I really wish I knew what kind of friction we'll have.

Thank you,



Craig Sink
Mechanical Engineer
Force Design, Inc.

 

[Timelord]

Perhaps you could put an ammeter on the existing conveyor and determine how much horsepower it requires and then go from there.

Timelord

 

[Fabrico]

Start with torque needed to spin the conveyor (including the maximum amount of cardboard) at 750FPM, then figure back to the HP at the motor.

 

[zekeman]

OK, for 750'/min and 4" dia drum, I get about 750 RPM output. Since
HP=2pi*torque*RPM/33000
Using my proposed 1/4 HP make the assumption that delivered HP=.18 after allowing some electrial and gearbox loss; solving for torque
T=HP*33000/(2pi*RPM)=.18*33000/6.28/750= 1.26 ft-lb, probably a little light if you include excess for startup torque (i.e. the torque you need to accelerate the inertial load to speed in reasonable time)
Why don't you build the unit and then test it for friction torque before designing the drive? Make sure you have a handle on the inertial load for startup, especially if you start/stop a lot.

 

[tygerdawg]

Two options for you to identify the HP requirement for this application:
(1) Google and download a PDF file on the net called "Smart Motion Cheat Sheet". It has all the formulas and descriptions needed to do this.
(2) Go to SEW Eurodrive's website and get set up to use their PTPilot application (it's free). Your conveyor system is one of their standard models. It will size a SEW gearmotor for your app. From that you can determine the HP requirement.


TygerDawg

 

[cwsink]

Thanks for the input everyone. I wish I had the time/opportunity to build the conveyor and test for required hp...but...customers rarely go for that!




Craig Sink
Mechanical Engineer
Force Design, Inc.

 

[barrind]

'Scuse me for butting in but this sounds like something I'm having to do at the minute. My situation is I am trying to calculate the total power needed to operate the rolls in a normaliser furnace. The drive powers 19 rolls each weighing approx 1T. The steel plate distrubuted between these rollers loads each roller up by approx 1.35T. Each roll is driven via a sprocket and chain drive. The chain is driven through a croftain clutch, gearbox and ultimately the motor. I've read that smart motion cheat sheet and it looks very useful. As I understand it, it seems to rely on adding up the inertias for the various parts of the mechanism which move and converting into an acceleration torque at the motor, and then adding the various torques required to overome static effects. I my application the weights of the chain and other drive elements are probably insignificant compared to the rollers and plate so would it be not so bad to ingore these elements? That would leave me just needing the inertia of the rollers and plate. Would it also be safe to ingore the static torque do you think. I appreciate more information is probably required to say for definate. The rollers are set to reverse direction every 30 seconds, I should be able to time the change over to get the acceleration.