Question

A constant torque 2.5 kw motor drives a riveting machine. The mass of the moving parts, including the flywheel is 125 kg at 70 cm radius. One riveting operation absorbs 10,000j of energy and takes 1.2 seconds. Speed of the flywheel is 240 rpm before riveting. Determine (1) no. Rivets closed per hour and (2) the reduction in speed after the riveting operation

Answer 1

Answer:

Explanation:

Given : p = 2500w

m = 125kg

K = 0.7 m

E1 = 1000Nm

Tp = 1s

N₁ = 240 rpm

(1) = 2π N/ 60

= 25.133 rad / s

To find  N₂ , No. of rivets / hr

E2 = p * Tp = 2500 Nm

triangle E = E₁ - E₂

10000 - 2500= 7500 Nm

l = mk2

= 125 * 0.7 ²

= 61.25 kg/ m²

Δ E = 1/2 ( W₁² - w₂²)

hence w₂² = w₁²- 2 Δ E / e

25.133 - 2* 7500 / 61.25

w₂ = 19.667 rad / s

N₂ = 187.8 rpm

total energy / hr