(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Calculate the motor size required to drive shaft A. (shown in schematic 1 diagram)

Drive shaft rotates at 75 Rpm.

Weight of plunger + attachments = 30kg's

Dimensions of plunger given in schematic 2.

2. Relevant equations

Work done = F x d (distance = radius of cam x 2 = .6m)

Power = work/time

3. The attempt at a solution

Neglecting the weight of the plunger and attachments to the drive shaft of the motor. I

Just looking at a direct relationship between maximum water displaced and power.

The maximum depth under water (Plunger profile) of 600mm x588 x 1219.2 displaces 215kg of water.

Force = 215 x 9.81 = 2109.15N

Work done = F x d = 2109.5 x.6 = 1265.5J

Power = Work/Time = 1265.5/(.4) = 3164 W or 3.164kW

Would I be right to recalculate this allowing for the weight of the plunger and attachments aiding the displacement of water? eg:

215-30=185kg

F = 185 x 9.81 ......etc?

Is my method here right? or am I way off on how this problem should be calculated?

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Help calculating power required to drive shaft

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