Mechanical Engineering - Theory of machines - Discussion

Usually, power transmission is proportional to belt speed.

However, at very high belt speeds which are usually above 1500 m/min, the power decreases with increase in the belt speed due the to rapid rise of centrifugal force acting on the belt. This centrifugal force reduces the pressure between the belt and the rim of the pulleys, and thus, move the belt away from the pulley and reduce the wrap angle. Therefore, the belt tensions and power transmission also are reduced.

However, at very high belt speeds (usually above 1500 m/min) , power decreases with increasing belt speed due to rapid rise of centrifugal force acting the belt. This centrifugal force reduces the pressure between the belt and the rim of the pulleys, moving the belt away from the pulley, reducing the wrap angle and hence, the belt tensions and power transmission.

Ans: C.

The centrifugal tension in belts does not Affect the power transmission.

Has no effect on the Power transmitted".

If T1= Tight side-tension, T2= slack side-tension, v= velocity of drive;.

P= (T1-T2)v.

Centrifugal tension (Tc) acts on both tight and slack sides:

P=[ (T1+Tc) - (T2+Tc) ]v.
P= (T1 - T2) we even after considering Centrifugal tension.

For smaller speeds it can be ignored. but for higher speeds it should be taken;

Without centrifugal tension, P= T1 (1-1/e^μθ)V
Considering centrifugal tension (Tc), P= T1-Tc (1-1/e^μθ)V. therefore power will be decreased. OPTION B is correct.

Power = (T1-T2) * Velocity.

When we take "Tc" in consideration. At that time we have to add "Tc" value in "T1" as well as in "T2". So, it will nullify the effects of "Tc". Because of this Centrifugal Tension doesn't affect Power transmitted.

It doesn't affect power transmission.

Power = (Tt-Ts)V.
Considering centrifugal tension.
Tt = T1 + TC. = tight side tension.
Ts = T2 + TC. = slack side tension.
Power = ((T1+TC) - (T2+TC))V.
= (T1-T2)V.

It doesn't affect power transmission.
Power = (T1-T2)V.

Considering centrifugal tension
T1 = T1 + TC.
T2 = T2 + TC.
Power = ((T1+TC) - (T2+TC))V
= (T1-T2)V.

P=T1[1 - 1/, ^μ*β]V.

Hence power transmission is lesser when Centrifugal force is taken into account.

P=(Tmax-Tc)*k*V.
If Tc=0, P is max.
If Tc#0, P is decreased.

Yes, C. There is no effect on power transmitted.