Question 44 (Textile Engineering & Fibre Science)
A bobbin leading speed frame running at 1000 rpm spindle speed is producing a roving with 2.5 turns per inch. The diameter of empty bobbin is 5 cm. When the bobbin attains 10 cm diameter, the percentage change in the bobbin speed will be approximately
(A) | 1 % |
(B) | 3 % |
(C) | 5 % |
(D) | 7 % |
[Show Answer]
Option B is correct.
Given-
Spindle speed=1000 rpm
TPI=2.5
Dia of empty bobbin(d1)=5cm
Final bobbin dia(d2)=10cm
% change in bobbin speed=?
TPI=Spindle speed/FRD
2.5=1000/FRD
FRD=1000/2.5
FRD=400 inch/min
FRD=400 x 2.5 cm/min
Front roll delivery(FRD)=1000 cm/min
In Bobbin lead speed frame-
Bobbin speed-flyer speed(spindle speed)=
Bobbin speed=flyer speed(spindle speed)+
Bobbin speed=1000+
At empty bobbin dia,
Bobbin speed 1=1000+
At 10 cm bobbin dia-
Bobbin speed 2=1000+
% change in bobbin speed=
% change in bobbin speed=
% change in bobbin speed=
% change in bobbin speed=
% change in bobbin speed=2.99 (Ans)