horsepower

'Move' could still mean 'Lift'. An elevator moves, but not normally sideways.

The key is that the force and the distance have to be in the same direction (dot product in vectors). It's a roaring PITA in the American system because we don't usually separate out mass and weight and that makes it harder to see what is going on.

But, you could imagine your shiftless brother-in-law () sitting in a stalled car with the brake on while you're trying to push it on a level road. If you apply 550 lbs of force and move it one foot in one second, you have 1 horsepower.

You might Google tractor pulls to see an example of this being done as a contest (minus the brother-in-law, of course).

Thank you TVP45

So could I caluclate the hp output of an horizontal vibrating conveyor using the lbs of product moved per foot per second?

I could then compare to the power consumed by the magnets to obtain the efficiency of the machine.

No. That's the confusion part. When you say lbs, that's the vertical force due to gravity. So, if you're moving horizontally, there is 90 degrees between the force and the distance and work = 0. So, you need to find the horizontal force, and that's gonna be complicated for a vibrating conveyer. I'd probably do this by borrowing (who knows from where) an oversized motor for which I know the hp vs current curve, hooking it up for some particular load on the conveyer, and then extrapolating.

The problem is that the product is loose foodstuff, nuts,crisps, bits of frozen meat(?) product for mcburgers and ready meal dinners crap etc.

If I pulled a bag of the stuff along on a skate board using a fishermans weighing spring and took a reading in lbs and subtracted the reading for pulling an empty skateboard would this give the force required.

Electrical bod here trying to do mechanical things.

<...Electrical bod here trying to do mechanical things....>

....then 1hp ≈ 746W.

I know PWSlack but I could not relate kgs/metre/second to watts and nobody on this forum could either.

I have to work with US engineers who only speak lbs, hp and gallons and the rest of the world who speak SI system and I've just completed 55 laps round the sun so my brain cell count must be down by zillions by now.

I know of no real engineer anywhere in the world who cannot make these unit conversions.

Pure nonsense.

I suspect that some on this forum are bored with the topic. It seems to come up often.

Almost any text book will have a units conversion table in the Appendix.

Paste one on your wall for reference.

To quote a wise old man:

"The metric system?! The metric system is the tool of the devil! My car gets 40 rods to the hogshead and thats the way I likes it!"

Avery Montembeault

Pure tomfoolery! Whay can't we stick with the FFS* system like our English ancestors.

* (FFS = Furlongs/Fortnight/Stone to the smart alect youngsters out there)

Thank you for your response.

Please tell me how I convert kg weight to kg force

The makers plate on your conveyors electric motor should give the motors horsepower @ its operating RPM as well as the voltage and amperage at same. Check the motor is operating at its normal RPM first and calculate the difference between the Hp rating ( converted to Kw) and the volts x amps figures n the plate. YOu could also check the actual voltage drop across the running motor and current by measurement. While it wont tell you the amout of mass you are shifting it ( the VA measurements) will tell you how much power you are consuming to move the stuff, which is exactly the amount of work being done!

P.s. An actual horse can only usually work at 1/2 horsepower!

'The makers plate on your conveyors electric motor should give the motors horsepower @ its operating RPM as well as the voltage and amperage at same. Check the motor is operating at its normal RPM first and calculate the difference between the Hp rating ( converted to Kw) and the volts x amps figures n the plate. YOu could also check the actual voltage drop across the running motor and current by measurement. While it wont tell you the amout of mass you are shifting it ( the VA measurements) will tell you how much power you are consuming to move the stuff, which is exactly the amount of work being done!'

The conveyors do not have motors, they are an horizontal cute that is vibrated by turning the a magnet on and off at 30Hz and varying the speed by control of the power to the magnet via a thyristor - more power = more movement. I have measured the power input with kWh meter, I need to know the work done in watts to obtain the efficiency.

This type of conveyor is common in food and pharmaceuticals as the shute can be kept sterile as opposed to a belt conveyor that has lots of hidden crevices for the bugs to hide in. When moving stuff vertically we have to resort to bucket elevators that are a nightmare to keep clean.

Hi PWSlack,

Horse power was originally defined by James Watt here in the Black Country where I live! To do this he placed a 10 ton steam driven narrow boat as used on the canals one mile from where I am living, next he placed a horse on the tow path which pulled the narrow boat in the opposite direction to which the boat was driven while the steam engine was was going flat out.

He then got the workmen to place so much coal in the narrow boat until the horse's pull negated the pull of the steam engine. The coal load was then weighed and this defined the horse power!

Spencer.

NO: if you move a ton of bricks from one place to another at the same height you haven't done any work (in the strict mechanical engineering sense).

If your skate board is frictionless then your fisherman's scale will only register a force when you are accelerating the load (in theory, and, in a perfect world you could recover all the work done when you decelerate the load to rest).

To calculate the HP required for a conveyor you need to combine several forces.

The first force is that of the friction of the belt itself. You have the vertical and horisontal forces expressed as

F = u W where u is the friction coeff and W is the weight of the load and belt.

The next is the friction of the rolling masses of the conveyor rollers.

Another friction component depends on the shape of the materials conveyed and the speed and is the air friction component.

You also have the change of momentum of the belt as it changes direction around the end rollers.

The last one is the elevation of the goods, that is the difference in height between the beginning and end of the conveyor.

If you have external forces like vibration, scrapers, dividers etc then you will have to know the horisontal and vertical components of these to be able to calculate the power required.

All the vibratory conveyors I'm familiar with are built with a metal pan that oscillates on fiberglass springs in an arc motion that actually throw the product slightly up and forward with each oscillation and advance the product slowly without belts, rollers or chains.

I would guess the speed of the oscillations, the mass of the product, the mass of the pan and friction of the product against the pan material would be primary factors.

Just don't ask me how to calculate it.

Since the lbs is the unit for force it doesn't matter which direction it is moving. The formula for horse power is P = F*v, where F is the force and v is the speed. So by definition MOVE will be more general than LIFT. Regards, Faruk

Get a new dictionary. Power is force exerted through distance divided by time (work/time). Vertical force is the weight, horizontal force could be less or more, depending on friction.

The 550 pound object is still subject to gravitational pull whether it is hanging in the air or sitting on the ground. What there is not a lot of is friction when lifting it vertically. If I remember right, the term horsepower was developed by coal miners or someone like that determining how many horses it took to pull a load of coal up out of a mine. I am probably wrong but, sounds good.

I've used the type of vibrating conveyor you're talking about. The magnet supplier will be able to give you information about load, throughput, etc.

This is one fifth of a horsepower shifting 2000lbs+ at 3 feet per second round Birmingham. He does notice the speed ramps.

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I'd love to know what's going on in that picture - it's brilliant !

Small pony shifting 2000lb generator for the BALSALL HEATH CARNIVAL in Birmingham. Nobody had a tow hook that fitted so we hooked it to the saddlechariot, which was hooked to Henry. On the basis that a shire horse is one ton, and Henry is approx 1/5th of a ton, he is generating 1/5th of a horsepower.

Simon

Thanks Simon,

Henry looks like a real character - you must get hours of pleasure. I really liked the shots you posted earlier on the beach ; totally cool.

Kris

horsepower has a dramatic error. Fans of turbod honda inline will never understand even if you scream the truth like thier engine..

The engine itslef, or source of power is to be subtracted from overall horsepower number. you have that covered in figuring power consumption. Very clever, and very important to decipher.

You may have heard the concept of torque and hp and folks favoring one or the other. Not a single HP on earth counts what itself as using as the power source...hence big hp on a draggin source is not the same as say, a 90hp 3 main bearing balanced frictionless boxer and a 130hp honda inline in the same vehicle...the boxer crushing the honda screaming fantasy with 30 less hp and nearly half the rpms (it has always been the counterbalancers and inline flaws,but that is a different subject, almost). This very misconception has gas prices driving motorheads mad...

Anyway, find a nice motor to do the work, and may you get the least consumption in your quest to get it right.I love this question....and the answer.