ACS550 for Winder and Unwinder Application

Hi,

I am working on printing inspection machine where 3 nos. ACS550 of smaller rating less than 7.5Kw on unwinder, main motor and rewinder but there will an issue of maintaining a TENSION. I have tried with one small roll it works fine but as i change the roll then issue with unwinder and rewinder.

Please reply ASAP.

not familiar with your system, but here are some ideas and I don't know if they apply to you.

moisture in the air lines.
water in your air lines on the machine.
air compressor oil is causing the valves / cylinders to stick.
any maintenance done on the machine lately?
any electrical / mechanical changes lately?
any plc programming changes?


are you using different paper thickness on rolls? that does make a difference and can cause issues.

james

Are you using motor torque to measure tension, or do you have a load cell on a roller?
Has the big roll ever run properly, or has it been like this since commissioning?

James Mcquade said:

not familiar with your system, but here are some ideas and I don't know if they apply to you.

moisture in the air lines.
water in your air lines on the machine.
air compressor oil is causing the valves / cylinders to stick.
any maintenance done on the machine lately?
any electrical / mechanical changes lately?
any plc programming changes?


are you using different paper thickness on rolls? that does make a difference and can cause issues.

james

Click to expand...

There will not be much any mechanical or pneumatic problem occurred. Thereis a machine next to me is working fine.

No electrical changes done.
I don’t have Plc program.

Different thickness and different rolls size(diameter).

I am using motor torque to measure tension. There will no load cell on the roller. The problem is when unwinder is with roll and rewinder is empty. Then the tension is not maintaining.

/sigh. Dragging information out...

#1: How are you trying to control the tension, actually? Is there a speed controlled element? Capstan? Surface wind/unwind drum?

#2: What are you trying to control tension on? Unwinder? Winder? Both? Both won't work without some sort of isolation.

#3: Are you compensating your torque commands for wind/unwind diameter? If so, how are you measuring/calculating diameter? Does it have to be preset? Line Speed / (Un)Winder RPM can calculate diameter, but is not very reliable when the line is first started.

#4: You say you have issue when you change roll. What exactly is the issue?

Motor torque = tension * roll diameter + angular acceleration * angular inertia

For heavier rolls, the inertia will be higher.
For fuller rolls, the roll diameter will be greater.

Consider:
- load cell on a roller
- constant force dancer arm to act as a buffer
- using maths and physics.