A simple question I think?

Hi, I haven't done any mechanical calulations for a few years now and having problems thinking this problem out, can anyone put my mind at rest?

Scenario: 2 conveyor belts running at 3m/s conveyor1 feeds conveyor2.

If conveyor2 increases to 4m/s would the load on the motor driving it increase or decrease?

I realise if they both were to increase to 4m/s the load would obviously increase, but if only conveyor 2 increases surely it would have less material on it and therefore less load on the motor. Am I thinking correctly? How can I prove or not prove this mathematically?

Thanks in advance

Rich

Reply to
rich
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Energy = force times distance. In this situation the same load is carried over the same distance... IF the only resistance is a constant friction then the energy and power required remain the same independent of belt speed. In practice some of the drag will be viscous... increasing with the square of speed. I would expect a small increase in power required, probably less than 10 %

Regards Jonathan

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Reply to
Jonathan Barnes

And power is force times velocity, no?

-- Ed Ruf Lifetime AMA# 344007 ( snipped-for-privacy@EdwardG.Ruf.com)

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Ed Ruf (REPLY to E-MAIL IN SIG!)

One way that I thought of that you can prove it mathematically is to look at the motor. Electric motors have a power curve. The power curve describes its output toque as a function of its RPM's. Depending on the type of motor (I assume that its speed is a function of voltage input) the power or energy required to achieve a desired RPM can be a function of voltage or current. If you look at the motor and the friction on the conveyor as a function of both load and speed, you should be able to easily show an increase in power consumption.

However, everything that I have just said could be moot if to increase the conveyor's speed you have only changed out the gearbox and the motor running the system had more than enough torque available to handle the system. In that case, the energy would remain the same, or else not increase significantly.

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YouGoFirst

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