Power Transmission by Belt Drives Power Transmission by Belt Drives
A common and simple method of transmitting power from one shaft to another is by means of a belt passing over pulley wheels which are keyed to the shafts,
Typical applications include an electric motor driving a lathe or a drill, and an engine driving a pump or generator.
For a belt to transmit power between two pulleys there must be a difference in tensions in the belt on either side of the driving and driven pulleys. For the direction of rotation shown in Figure 1 F₂ > F₁
The torque T available at the driving wheel to do work is given by:
where
F₂ is tension force in belt on driving pulley
F₁ is tension force in belt on driven pulley
rx is radius of driving pulley
and the available power P is given by:
Power Transmission by Belt Drives Study Mtaerial
A common and simple method of transmitting power from one shaft to another is by means of a belt passing over pulley wheels which are keyed to the shafts,
Typical applications include an electric motor driving a lathe or a drill, and an engine driving a pump or generator.
For a belt to transmit power between two pulleys there must be a difference in tensions in the belt on either side of the driving and driven pulleys. For the direction of rotation shown in Figure 1 F₂ > F₁
 |
| FIG 1 |
T = (F₂- F₁) rx Nm
F₂ is tension force in belt on driving pulley
F₁ is tension force in belt on driven pulley
rx is radius of driving pulley
and the available power P is given by:
P = T𝟂= .(F₂ − F₁) /rx 𝜔𝚡 watts
where
𝜔𝚡 is angular velocity of driving pulley
re T = P / (2 𝜋 n )
the linear velocity of a point on the driver wheel
vx = rx ωx
Similarly, the linear velocity of a point on the driven wheel
vy = ry ωy
Assuming no slipping, vx = vy i.e. rx ωx = ry ωy
rx (2 𝜋 nx ) = ry ( 2 𝜋 ny )
where
nx is rotating speed of driving pulley
ny is rotating speed of driven pulley
ry is radius of driving pulley
Percentage efficiency= (useful work output/power input) × 100
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