Medium Voltage Drive 800kW 6.3kV For Cement

1. What's the relationship of ISTECH and CNC Electric Group?
Shanghai ISTECH is a subsidiary of CNC Electric Group, which established in 1988, Top 500 electric enterprise in China.

2. What's the Variable Frequency Drive ?
Variable Frequency Drive is shortname as VFD, VSD, Inverter, AC Drive and so on. Which can adjust the motor's rotator speed, change the frequency.

3.What's the basic functions of VFD?
1)Soft start,  2) Stepless speed regulation, 3) Energy saving, 4)Multiple protection,  5)Automation.

4.How long the life of VFD?

Although VFD is a static device, but include the consuming device such as filter capacitor, cooling fan. If they are regular maintenance, VFD is expected to use for more than 10 years.

5.What's the difference between Soft start and VFD?
Soft starter is actually a voltage regulator for motor starting, only change the output voltage; VFD not only change the

voltage, but also the frequency, adjusting the motor's rotator speed.

6.How to select the suitable VFD according to the different load?
A. Fan and Pump: Normally, select the same power capacity of VFD for motor. (But Air compressor, deep water pump, mud pump, the rapid change of the music fountain need to increase capacity).

B. Crane: Due to Start impact is very big, select the more power capacity of VFD for motor. Meanwhile, when the weight is lowered, there is an energy feedback, so the brake unit or the common bus mode is used.

C. Uneven load: Sometimes light weight, sometimes heavy, should select the power capacity of VFD according to the heavy load, such as steel rolling mill machinery, crushing machinery, mixer, etc..

D. Large inertia load: Select larger power capacity of VFD for this kind load, to speed up the start and avoid oscillation.