IComp is the creation of

and has been put into App format by Clarence Klassen/Steven Abbott

**Clarence Klassen**of KlassENgineering Inc., klassen.on.caand has been put into App format by Clarence Klassen/Steven Abbott

Metric Units
US Units TextMode

IComp is the creation of **Clarence Klassen** of KlassENgineering Inc., klassen.on.ca

and has been put into App format by Clarence Klassen/Steven Abbott

and has been put into App format by Clarence Klassen/Steven Abbott

Density represents the density of the web.

Choose a Web, select the value and copy it.

Close this form and paste value into Density in Text Mode.

Web | g/cm³ | lb/in³ |

Acetate | 1.32 | 0.0477 |

PC | 1.20 | 0.0434 |

PE | 0.93 | 0.0336 |

PET | 1.40 | 0.0506 |

PMMA | 1.18 | 0.0426 |

PP | 0.90 | 0.0325 |

OPP | 0.946 | 0.0325 |

PVC | 1.40 | 0.0506 |

Nylon 6 (PA) | 1.13 | 0.0408 |

PI | 1.47 | 0.0531 |

Board | 0.83 | 0.030 |

Bond | 0.69 | 0.025 |

Magazine | 1.11 | 0.040 |

LightWeightCoatedPaper | 0.97 | 0.035 |

MachineFinishedCoated | 0.97 | 0.035 |

NewsPrint | 0.69 | 0.025 |

FineCoatedPaper | 0.97 | 0.035 |

SuperCalendared | 1.11 | 0.040 |

Tissue | 0.28 | 0.010 |

Aluminium | 2.71 | 0.098 |

Steel | 7.80 | 0.282 |

Motor Inertia represents the Inertia of the spool.

Choose a spool material, select the value and copy it.

Close this form and enter a value into Spool Inertia.

Mtr Pwr | Mtr Pwr | Inertia | Inertia |

kW | HP | kg*m² | lb*ft² |

7.46 | 10 | 0.025 | 0.60 |

11.2 | 15 | 0.031 | 0.73 |

14.9 | 20 | 0.035 | 0.83 |

18.6 | 25 | 0.077 | 1.82 |

22.4 | 30 | 0.089 | 2.12 |

29.8 | 40 | 0.125 | 2.96 |

37.3 | 50 | 0.164 | 3.89 |

44.8 | 60 | 0.319 | 7.56 |

56.0 | 75 | 0.395 | 9.37 |

74.6 | 100 | 0.468 | 11.1 |

93.3 | 125 | 0.539 | 12.8 |

Motor Base RPM is the RPM the motor will turn at when energized with rated voltage and frequency. Typically 1150 or 1750 RPM. The Base RPM is shown on the motor nameplate.

In web handling, we are concerned with the inertia of rotating bodies (rollers). This is called the

Torque is required to accelerate a roller. The greater the inertia, the greater the torque required. The

A driveâ€™s speed regulator is incapable of accurately accelerating the roller with the line pacer. The speed will always lag behind the speed reference when the speed is changing (ramping). We can compensate for this speed lag with inertia compensation. Inertia compensation for a fixed roller adds a torque proportional to the inertia when accelerating at a fixed rate. Inertia compensation is suggested for all rollers if tension requirements indicate that all rollers accelerate together.

While Inertia Compensation should be considered for a fixed roller, it is almost always required for winding rolls if the line speed changes. That is because there is a huge change in inertia between the core diameter and the maximum diameter of a roll. The inertia of the roll increases with the 4

Here are some examples of inertia for a 2m wide roll of several products.

OPP | Paper | Aluminum | Steel | |

100mm core (kg*m^{2}) | 1.0 | 1.0 | 1.0 | 1.0 |

500mm roll (kg*m^{2}) | 11.2 | 7.2 | 31.0 | 94.9 |

Density (gm/mm^{2}) | 0.946 | 0.600 | 2.700 | 8.000 |

As the diameter changes, the RPM decreases. The torque required for accelerating the roll is Moment of Inertia * Angular Acceleration. The Inertia of the roll increases as diameter

The important outputs are:

- The maximum torque which generally occurs at the maximum roll diameter.
- The minimum torque which generally occurs just above the core diameter.
- The diameter at which minimum torque occurs.
- The actual power the roll requires to accelerate at maximum diameter.
- The required motor nameplate power required to accelerate at maximum diameter. This is higher than the actual power by the ratio of maximum diameter/minimum diameter. This is lowered by increasing gear ratio.

**Summary of Inputs and Outputs**

The aim is to calculate the extra tension in the web caused by an increase in web speed of ΔV. This depends on the following inputs,
along with derived output values

Inputs | |||

Span | Distance between rollers (m or in) | ||

Gauge | Thickness of web (mm or mil) | ||

Width | Web width (mm or in) | ||

Speed | Web speed(m/min or ft/min) | ||

Accel | Acceleration Rate (m/min² or ft/min²) | ||

Density | Elastic Density of the web(GPa or MPSI) | ||

Outputs | |||

Area | Cross-sectional area of the web (m² or in²) | ||

Tc | Time Constant of the tension response to a change in speed at the 2nd roller (s) | ||

Gain | Steady-state Gain of the tension response (N/m/min or lbf/ft/min) |

For unwinds (or winders), there is a specific diameter where the inertia compensation exactly matches the tension torque during acceleration (deceleration). At this diameter the unwind brake (winder drive) produces no torque, but the tension is correct. Under this circumstance, we often hear the drive train gears and couplings chattering.

For unwinds, the most thermal stress is put on the motor when decelerating with a large roll. That is because tension and deceleration both act in the same direction. This occurs while stopping to patch a web defect just after accelerating with a large roll. Moment of Inertia is the biggest factor in tuning the speed regulator.

If an unwind or winder drive is used for threading the line, the tuning should be optimized for the diameter at which the line is most often threaded. For unwinds, that is at a large diameter. For winders that is at core diameter.