Case 10, crane, skip class load

Crane, dump and load torque big and smooth, positive and negative frequent and reliable. Frequency conversion device control crane, skip to rotary joints meet these requirements.
An only child mountain petrochemical factory ketone benzene workshop for three table filter installation and setup a 20 tons of bridge crane, technological requirements of explosion-proof, use explosion-proof squirrel-cage motor. The original production of lifting the owner hook, auxiliary hook, cart, car no speed regulating function, can't positioning. Torque is small, the hoist objects glide to lifting 19 tons of filter base, so that the workshop start late more than a year, a loss of ten million yuan. In July 91 the frequency control of motor speed and braking function, make main hook, auxiliary hook, cart, five motor car by a frequency converter control, the effect is very good. Overload test sling 22 tons, quickly put the three table each heavy 40 tons of rotary union filter installed in 10 meters high floor platform on the flight.
Dock port, station gantry crane, yard material piling and taking machine and so on all can use frequency conversion speed control device, in order to achieve reliable, steady, power saving, less maintenance purpose.
Frequency conversion speed control device, in addition to saving electricity significant outside, or some production process the necessary equipment.
Examples of 11, converter class load
Converter class load, with ac frequency conversion instead of dc unit is simple, reliable, stable operation.
On May 1, 1994, chengde iron and steel company steel plant three sets of 20 tons converter dc drive system all in fault condition. Quasi looking for a "fast and good" restore production control mode, please come to the China electrical rotational experts LiuZongFu professor. In professor liu's suggestion, the company manager finalize, 20 tons converter tilting and oxygen lance lifting adopts ac frequency conversion speed regulating drag. From supply to installation, commissioning, after 13 days, three sets all converter normally put into production. This is our country 20 tons converter tilting and oxygen lance lifting first using frequency control of motor speed. After years of production and application, this system operation is stable and reliable, and technical index fully meet the technological requirements. Converter, oxygen gun main drive system caused by the heat down to reduce more than 90%, the year yield increase by 15000 tons, power saving 220000 degrees, direct economic benefits is 2.31 million yuan. For steel mill stable production after lay a solid base to wear  this system in 1995 through the ministry of machine building appraisal, and was awarded the first prize in hebei province technology progress.
Case 12, special power class load
Many power, such as experimental power supply, the plane drag power supply (400 hz) can be used frequency conversion device to complete, the advantage is less investment, quick effect, volume some  simple operation.
Viscose fiber industry spinning equipment are mostly high speed motor, numerous hasp motor for 150 hz / 160 v. For a long time, the domestic viscose industry has been to use electric - generating set medium frequency power supply, says the dynamic frequency. Because this method malady too much, and gradually by ac frequency conversion power supply, says static frequency conversion. Shaoyang chemical fibre factory is the first application of viscose industry by static frequency manufacturers, eight Taiwan 160 kw converter points two groups power supply (each group a standby). Since December 1992, since the production, than the dynamic frequency have obvious advantages.
A. and reliable. Operation for many years, and not failure trip.
B. the operation is stable, and the voltage and frequency fluctuations very some 
C FM convenient, for the factory production of different twist silk cake created conditions.
D. little noise and improve the operation personnel's environment.
E. Improve the product quality. The first phase project (the dynamic frequency conversion power supply), viscose filament percent of pass is only 55.1%, the first grade percent of pass is zero, second percent of pass is 20%, and the second phase project (using static variable frequency power supply) average qualified rate 98.12%, grade a qualified rate 88.7%.
F. increased production. A phase of the project design capacity of 2000 tons/year, trial production half a year, yield only 65.53 tons, and of the second phase of the project design capacity of 1000 tons/year, trial production half a year, production filament 685.25 tons, greatly more than design capability.
G. power saving 13%.
Due to the static frequency conversion for viscose industry has brought great benefits, many enterprises, such as jilin chemical fibre factory, jiujiang chemical fibre factory, yibin chemical fibre factory, hubei chemical fibre factory, dandong chemical fibre factory, weifang chemical fibre factory (except yibin outside, belong to the listed company) are adopted static frequency conversion technology.
Frequency control of motor speed in addition to saving electricity outside, and increase production and consumption, the high quality effect. Because it has a volume some  light weight, high precision, strong commonality, the craft is advanced, the function rich, protection is complete, high reliability, easy operation etc, by using personnel welcome, frequency control of motor speed it is to fiber optic rotary joint save energy and reduce consumption, high quality and high yield of the ideal equipment, is entering into the 21st century's first drive technology, benefits the country and the people.