# Loom Speed Calculation in Weaving Formulas & Examples

Loom Speed Calculation:
The speed of a plain loom depends on the reed space of the loom. Wider the loom more is the time taken by the shuttle to pass from one box to another, the speed of a loom fitted with a dobby, jacquard, or a drop-box mechanism will be less than the speed of a plain loom of the same reed space because some other factors come into play. In the other case of jacquard or a dobby, the shedding controls the speed of the loom. A double lift dobby or double lift jacquard loom will have a higher speed than a single lift dobby or a single lift jacquard loom respectively. Here, loom speed calculation in weaving formulas & examples are discussed as follows:

In the case of a drop-box loom, the box motion will control the speed. A loom with a negative drop-box motion will have a lower speed than a loom with a positive drop-box motion.

In automatic looms, generally a shuttle changing loom has a higher speed than a cop changing loom. Looms are generally driven either from a line-shaft or by individual motors fitted with them.

### Loom Speed Calculation in Weaving Formulas & Examples

The following formulas will be used during calculating loom speed in weaving:

1. R.P.M of crankshaft or R.P.M of the loom,

….Diameter of line shaft drum × R.P.M of line shaft
= ………………………………………………………………………..
…………………….Diameter of loom pulley

2. Diameter of loom pulley,

…..Diameter of line shaft drum × R.P.M of line shaft
= …………………………………………………………………………
……………………..R.P.M of crank shaft

3. Diameter of line shaft drum,

….R.P.M of crank shaft × Diameter of loom pulley
= ……………………………………………………………………..
……………………..R.P.M of line shaft

4. R.P.M of line shaft,

……R.P.M of crank shaft × Diameter of loom pulley
= ………………………………………………………………………….
………………..Diameter of line shaft drum

Example 01:
A line shaft of a weaving shed makes 130 r.p.mn. The diameter of the line shaft drum is 14 inches. If the diameter of the loom pulley is 10 inches, find out the r.p.m. of the loom.

Solution:

R.P.M of the loom,

……Diameter of line shaft drum × R.P.M of line shaft
= ………………………………………………………………………….
………………..Diameter of loom pulley

…..14 × 130
= ………………..
…………10

= 182

So, R.P.M of the loom is 182

Example 02:
Calculate the size of the loom pulley required to impart a speed of 200 r.p.m. to a loom which is driven from a line shaft of 120 r.p.m. The line shaft drum has a diameter of 5 inches.

Solution:

Size of the loom pulley,

….Diameter of line shaft drum × R.P.M of line shaft
= ………………………………………………………………………..
………………………R.P.M of crankshaft

…….120 × 15
= ………………….
……….200

= 9 inches.

So, the Size of the loom pulley is 9 inches.