yarn speed

Have a winding machine that was built in Italy that is basically a DC motor with a dancer arm that slows down the machine as yarn is wound onto a cone.
Has anyone used or had any experience with some type of sensor that might could be used that the yarn could be fed through to tell how fast the yarn is being pulled?
Thanks for any advice.

Must we assume that you would need a non-contact type of sensor? You can't for example wrap the yarn around a wheel attached to an encoder can you?

Or are you looking for something similar to an ammeter which go around the wire without touching it to measure the Current.

If you need non-contact then you can google the term Velocimeter.

There are a few devices out there which utlise lasers to measure the speed of an object.

http://www.polytec.com/us/products/speed-and-length-sensors/lsv-1000-laser-surface-velocimeter/

the dancer arm should have a rheostat mounted on it that controls the speed of the DC motor... pretty common in spinning mills of the 80's & 90's.

If you can measure the diameter of the wound roll and the time it takes for one rotation you can calculate speed. PI times diameter is circumference. Divide that by the time of a rotation to get speed.

You can use an encoder in a sheave on the dancer arm to measure both footage and speed. The circumference of the spinning wheel varies slightly with the diameter of the yarn, but it should be more than accurate enough .

http://www.laserspeedgauge.com/index.php/en/

We have used this for measurement of wire and cable.

Regards,

+1 on the Beta Laserspeed. It can communicate directly to most PLC's, and if that is impossible, or you are just using a counter, it can generate a quadrature output just like an encoder.

beta laserspeed looks interesting, but this is a very small diameter yarn type fiber material like you would see on a knitting machine. It is wound directly out of a extruder using a Leesona Fiber Winder that is basically a DC motor with a dancer arm and a take up roller that a cone is placed on then the fiber is wound on the cone and a guide oscillates back and forth to evenly roll the fiber onto the cone.
From your experience if the laserspeed detector was looking at the center of the cone that the fiber is would around, as the fiber wound around the cone and increased in diameter would the laserspeed detector be capable of displaying how many feet per minute the cone was turning?
Also, what is the cost for one of these units?
Thanks