Troubleshooting primary and secondary reeling devices
May 29, 2018
The following are general troubleshooting tips for primary and secondary reeling devices.
Limit Switch or Movement Malfunction
Symptom: Disturbance alarm is given after timeout.
If alarms occur repeatedly, the timeouts should be increased. If the alarm remains active, there is a physical fault in the machine.
Probable cause: The device has not moved away from the limit switch, although the control is on.
Correction: Check whether the control reaches the valve, i.e. whether the LED on the valve cap is on. If the LED is on, there is a malfunction in valve or hydraulics. Check the valve coil. If the LED is not on, there is an electrical fault. Check the fuse, relay, and wiring.
Probable cause: The device has moved away from the start limit, but it has not reached the end limit.
Correction: Check whether the movement has been mechanically completed. If the movement is not completed, check whether there is a mechanical obstacle. If the movement is completed, check whether the limit switch flag has been bent and whether the limit switch functions.
Probable cause: The program does not know if the device has moved, because the device has not reached the limit switch.
Correction:
- Check whether the movement has begun. If no movement has taken place, check whether the valve is receiving controls, i.e. the LED is on on the valve cap. If the LED is on, there is a malfunction in valve or hydraulics. Check the valve coil. If the LED is not on, there is an electrical fault. Check the fuse, relay, and wiring.
- Check whether the movement has been mechanically completed. If the movement is not completed, check whether there is a mechanical obstacle. If the movement is completed, check whether the limit switch flag has been bent and whether the limit switch functions.
Locking Clamp Limit Switch Does Not Detect Limit Switch Flag
Symptom: An alarm is given and other primary reeling device functions are prevented.
Probable cause: Limit switch flag is distorted.
Correction: Repair the limit switch flag and check the limit switch function.
Locking Clamps Cause a Linear Load Malfunction
Symptom: A trace indicating the locking clamp opening point can be seen on the parent roll end.
Probable cause: There is too much material on the locking clamp tips. The locking clamps rotate the bearing housing of the reel spool when the locking clamps open.
Correction: On grounds of the wear mark, material is ground away from the locking clamp tips.
Probable cause: The down position of the primary reeling device has been incorrectly adjusted, either too low or too high.
Correction: Adjust the down position according to OEM instructions.
Movement of the Locking Clamps Does Not Function Normally
Symptom: Movement speed has become slow, movement stops half way or, in spite of control, the locking clamps do not move.
Probable cause: The mechanically-controlled safety valve is causing disturbance.
Correction: Align the wear pieces acting as guide surfaces and the mechanical control lever of the valve.
Reeling Is Not Possible with Low Linear Load
Symptom: The nip does not close properly.
Probable cause: The linear load reference value is not sufficient to close the nip because the frictions or zero points have changed.
Correction:
- Increase the linear load reference value.
- Check the zero points of the load measuring cells and adjust them, if necessary.
- Make a visual inspection of the condition and lubrication of the guideways.
Linear Load Problem at an Angle
Symptom: At an angle the nip opens in load control. This problem does not occur when reeling on rails.
Probable cause: The fault is related to relief calculation. For example, the calculated paper mass may be incorrect in the load relief calculation.
Correction: Check the measurements and masses used in calculation.
When the Nip Closes, There Is an Excessive Linear Load Peak
Symptom: The paper is cut into strips in the reel drum grooving and the web breaks.
Probable cause: Nip closes askew or at a too high speed.
Correction: Readjust the nip closing speed.
Probable cause: Nip closes with excessive force.
Correction: Decrease the nip closing linear load value.
Probable cause: The paper is too dry.
Correction: Check the paper moisture content and adjust it to be correct.
Primary Coupling Does Not Engage
Symptom: Locking clamps are closed, but the coupling does not engage.
Probable cause: The interlock enabling the movement fails to become active.
Correction: Find the missing interlock on the Help display or the ladder logic. The preventing interlock may be caused by a loose limit switch or limit switch flag.
Primary Coupling Limit Switch for Closing Does Not Detect the Coupling
Symptom: The primary coupling moves back and forth.
Probable cause: Primary center drive does not make an engagement rotation. Cogs hit against each other and the coupling cannot close.
Correction:
- Check the reel electric drive HMI screens or ladder logic to see whether the primary center drive has run permit.
- Remove the cause of the malfunction and acknowledge it from the electric drive panel.
Probable cause: Limit switch or limit switch flag is loose or damaged.
Correction: Check the operation of the limit switch.
Engagement Force of Primary Coupling Is Insufficient
Symptom: Engagement of primary coupling is not easy. Primary coupling may also occasionally open when reeling under high torque.
Probable cause: The hydraulic pressure reducing valve is adjusted incorrectly.
Correction: Adjust the pressure reducing valve in accordance with the hydraulic diagrams. Use a pressure gauge for this purpose.
Probable cause: The coupling and reel spool are not aligned with each other.
Correction: Check the coupling alignment. The primary reeling device must be in up position and coupling engaged. Rotate the coupling back and forth manually; there should be a clearance. If there is no clearance, align the coupling according to the instructions.
The Primary Center Drive Does Not Turn Down or the Nip Does Not Close
Symptom: The primary center drive does not turn down or the nip does not close.
Probable cause: Speed sync is missing from the drives.
Correction:
- Check that the primary center drive and reel drum drive are in the same mode, e.g. run, crawl or stop.
- Check the event list for any sync data. Check whether the primary center drive and reel drum drive are both running approximately at the same speed. If necessary, increase the speed window in the electric drive program.
- If necessary, stop the electric drives. In Stop mode, the speed sync signal comes provided that the link functions.
At the Torque Change, the Reel Drum Torque Does Not Remain Constant
Symptom: Traces of the load change can be clearly seen on the parent roll end.
Probable cause: The losses in the calculation of the electric drives are erroneous.
Correction:
- During a web break, organize the following situation: the primary reeling device is in the up position where the empty reel spool rotates at the operating speed. The reel drum rotates at the operating speed.
- Check from the reel drum column on the main page of the drives if the difference between the loss and peripheral force is significant. The difference equals the error in the loss value.
- Check from the primary center drive column on the main page of the drives if the difference between the loss and peripheral force is significant. The difference equals the error in the loss value.
- If necessary, measure the frictions and update the values in the program for the electric drives.
Turning Fails to Start
Symptom: Primary reeling device does not move when pushbuttons are pressed.
Probable cause: The interlock enabling the movement fails to become active.
Correction: Find the missing interlock on the Help display (if available) or ladder logic. Preventing interlocking may be the result of a loose limit switch or limit switch flag.
Probable cause: Angle measurement is out of range or there is an I/O fault.
Correction: Check the operation of the angle measurement and set the zero point according to the instructions.
Turning Control Is On, But There Is No Movement
Symptom: Reel signaling device gives an alarm, but nothing happens.
Probable cause: Power failure.
Correction: Measure the power supply voltage and control voltage of the valve from the terminal blocks, from which the device cable runs to the valve cap. If the voltages are not found, check and repair the electric circuit using the circuit diagram.
Probable cause: Hydraulic or valve fault.
Correction:
- Carefully press the valve stem alternately in both directions. If there is no movement, there is a hydraulic fault. Locate the fault using the hydraulic diagram and pressure gauge. Check whether the block receives supply pressure or whether the pressure goes toward the hydraulic cylinder.
- If the primary reeling device moves when pressing the valve stem, there is a valve fault. The valve must be replaced unpressurized following the hydraulic OEM instructions. Make sure before changing the valve that the turning control switches on according to the monitor display and that the valve receives control voltage.
Turn Fails to Reach Rails
Symptom: Reel spool is slightly off the rails. Reel spool drops a little when the locking clamps are opened.
Probable cause: The mechanical stopping pieces are too high.
Correction: Re-shim the stopping pieces according to the instruction.
Probable cause: The reference value for turning speed is insufficient for slow turning.
Correction: Increase the reference value for slow turn on the tuning page or in ladder logic. However, the reference value must be so low that the primary reeling device does not drop heavily onto the rails.
Probable cause: Angle measurement or the lower limit switch stops the turning, but the directional control valve does not open.
Correction: Check the directional control valve coil/control with a magnetic pen. Replace the coil or valve, or repair the possible electrical fault.
Turn Fails to Slow Down Sufficiently Before Rails
Symptom: There is a hollow sound when the turn reaches its lower position.
Probable cause: The value of the deceleration angle is too high.
Correction: Decrease the deceleration angle value on the tuning page or in the ladder logic.
Probable cause: The value of the turning stopping angle is too high.
Correction: Decrease the value of the turning stopping angle on the tuning page or in the ladder logic.
Probable cause: The reference value for turning speed is too high for a slow turn.
Correction: Decrease the reference value for a slow turn on the tuning page or in the ladder logic. However, the reference value must be so high that the primary reeling device moves.
Turning Movement Stops Too Soon
Symptom: Turning begins but stops at an incorrect angle.
Probable cause: The angle value does not change sufficiently within the set monitoring time.
Correction: Check the angle value on the display and whether it corresponds to reality. Check the operation of the angle measuring sensor. The magnet of the angle measuring sensor may be loose or twisted.
Probable cause: This results in a measurement peak that stops the turning.
Correction: Check the angle value on the display and whether it corresponds to reality. Check the operation of the angle measuring sensor. The magnet of the angle measuring sensor may be loose or twisted.
Reel Spool Is Not Aligned with the Reel Drum
Symptom: Nip does not close over its entire width nor does it hold. Problems in tail threading.
Probable cause: The turning movement does not keep in sync and stops aslant at the angle.
Correction: Adjust the lengths of the rigging screws according to the OEM instructions.
For assistance troubleshooting your reel operations, contact your Valmet representative.