BMR SFU 0102, Manual

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SFU 0102/0202 Frequency Converter
1. Introduction
Depending on its construction, the speed of a three-phase a.c. motor is directly dependent
on the number of poles and the frequency of the network. In a 3ph 380V/50Hz network,
with a 2-pole motor, the rated speed would be 50 U/s * 60 = 3000 Upm.
With d.c. motors (brushless d.c.), the speed is dependent on the voltage applied
Three-phase a.c. motors provide numerous benefits in industry, such as brushless operation,
freedom from wear and tear, favourable capacity/weight ratio, high-speed capability, and
much more. These motors can be used many different application areas, such as milling and
grinding spindles, or with drilling machinery, for example.
D.C. motors have the advantage of a high power efficiency (approx. 85%) when compared
with a.c. motors, but the disadvantage of not quite reaching the torque of an a.c. motor at
low speeds (when starting), nor reaching the high speeds of an a.c. motor. However, the
higher efficiency also means cooling requirements are lower and dimensions can be smaller.
In the aforementioned applications, three-phase a.c. motors are operated using special
control gear – frequency converters. These frequency converters convert the fixed 50 Hz
network into a 3-phase network with variable frequency and voltage. This greatly reduces
the start-up problems and the high starting currents that are inevitable when high-capacity
three-phase a.c. motors are connected to a fixed network. The motor is controlled according
to a special characteristic curve until its rated speed has increased, or it has been stopped.
The SFU 0102/0202 - series frequency converter has been specially designed for use in these
high frequency applications, offering excellent safety, performance and reliability, the result
of years of experience in the design and construction of frequency converters, together with
the use of the latest materials and the most reliable components. It can be used in many
different applications and is as equally suitable for use as a replacement device in existing
systems with older type series as it is in pre-planned applications as a cost-effective solution,
helping to prolong the useful life of tools. In addition, both a.c. and brushless dc motors can
be operated by this high frequency converter.