Summary: In this paper, through introducing INVT GD5000 medium voltage inverter applied to pulper in the papermaking factory in Romania, to illustrate VFD transformation of the feasibility and many advantages after using mv drives.
Keyword: GD5000 MV inverter, pulper, soft start.
The pulper is an important device at the beginning of the process of papermaking. The pulper is mixed the recyclable paper and water equably, after mixing and stirring they become pulp.
In traditional ways, the papermaking factory use grid power directly driving the pulper. There are lots of disadvantages by this way. Such as large impact current when starting the pulper, can’t automatic controlled by DCS or PC system, easily blocked by plastic and etc. These problems always perplex the papermaking factory.
As the development of inverter technology, many papermaking factory customers realize that using inverter to drive pulper is much better than original ways.
ECOPAPER papermaking factory is very big factory in Romania. The average production of paper capacity is about 1000 tons/day.
Detailed motor parameters are list as follow：
Table 1 Motor Parameters
|Motor Model||Power||Rated Voltage||Rated Current||Rated Speed||Power Factor||Load Type||Quantity|
Figure 1, the pulper control system
Figure 2, the recyclable paper conveyor
Figure 3, the pulp tank (From bottom to top)
Figure 4, the paper production
According to the customer requirement, we choose the GD5000 series medium-voltage inverter, produced by Shenzhen INVT Electric CO., LTD.
The MV inverter model is Goodrive5000-A1600-06-S with bypass cabinet. Below table is the details of MV inverter parameters：
Table 2 MV inverter Parameters
|MV inverter Model||Rated Capacity||Rated Power||Rated Voltage||Rated Current|
Below figure is about inverter system diagram:
Figure 5, System diagram of the inverter
Figure 6, the motor and pulper
Figure 7, Goodrive5000 MV inverter
Figure 8, the pulper running current curve
4.Application and Advantage
After using inverter, there are some advantages as follow,
1) Soft start; The speed of pulper can running from 0 to rated speed, the acceleration time adjustable as the customer need.
2) Easily control by DCS; With digital and analog connection, it is easy to control;
3) Low harmonic. Without harmonic pollution to the motor and efficiently drop the heat of the motor. Increase the input power factor.
4) Reduce the loss of shutdown maintenance and save plenty of maintenance costs.
5) Running direction flexibility. When the customer find the pulper is blocked, they can use reversal jog function, after running at reversal state for some seconds the pulper continue running at forward state.
After using INVT Goodrive5000 series MV inverters to drive pulper, the inverter can meet with the customer requirement, which can automatic control by DCS system and soft start. Good operation of the inverter, obtained the customer widely recognized.
 Goodrive5000 Series High-voltage Variable Frequency Speed Control System Manual. Shenzhen Invt Electric CO., LTD.