Calculate Motor Power in kW for 15 Tonnes, 16 m, 0.2 m/s

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SUMMARY

The discussion focuses on calculating the motor power required to move a 15-tonne crane trolley over a distance of 16 meters at a speed of 0.2 m/s. The primary formula referenced is F = m*a for determining the force needed to accelerate the trolley. However, the conversation emphasizes that the power calculation must also consider friction, which can be negligible in certain scenarios, such as when using a rack and pinion system. The key takeaway is that energy is calculated using the formula 1/2 m V^2, and power is derived from energy divided by time.

PREREQUISITES
  • Understanding of Newton's second law (F = m*a)
  • Basic knowledge of power calculations (Power = Energy/Time)
  • Familiarity with friction concepts in mechanical systems
  • Knowledge of rack and pinion mechanisms
NEXT STEPS
  • Research the impact of friction in mechanical systems, particularly in crane operations
  • Learn about energy calculations in motion, specifically using the formula 1/2 m V^2
  • Explore motor selection criteria for heavy loads, focusing on torque and power requirements
  • Investigate the design and functionality of rack and pinion systems in lifting applications
USEFUL FOR

Mechanical engineers, industrial designers, and anyone involved in selecting motors for heavy machinery applications will benefit from this discussion.

enginecadet88
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Homework Statement



Ok so i need to choose a motor that is capable of moving 15 tonnes (metric) over a distance of 16 m at 0.2 m/s.

So, I am guessing i need to first find the force required to move this object which would be F=m*a. Is this right?

Now, what would be the equation to find the power required in Kw?


Homework Equations





The Attempt at a Solution

 
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No, f=ma is only the force needed to accelerate it upto 0.2m/s
The power is mainly to overcome friction.
You need to know what friction is involved, consider how hard it is to drag a 15tn rock over concrete compared to how much power you need to pull a 15tn boat.
 
Ill give some more background. The calculations i need really don't have to go into too much detail though.

This equation is for a crane trolley of 15 tonnes (metric) which moves along 2 beams. So, it is not a metal on metal contact. It will be a set of wheels or more accurately a rack and pinion set. Are there equations which do not take friction into account as i have been told by my lecturer that friction can be disregard.
 
Neglecting friction it takes no power to keep the trolley moving at any speed.
To get it moving you have to put in energy = 1/2 m V^2, how quickly you do this (ie how long you take to accelerte it ) determines the power (power is energy/time)
 

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