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CHAPTER 3 - Installation of the drive
3.3 Guidelines on the application of electromagnetic compatibility
3.3.1
This paragraph is compiled observing what prescribed in paragraph 1.4.3 of the standard on
electromagnetic compatibility for drives [8].
3.3.2
The necessity to fulfill precise standards as regards EMC is due to the ever increasing use of
power electronic devices, which, for the techniques used, are a source of disturbances in a
very wide range of frequencies (emission) and, at the same time, are sensitive to
disturbances produced by other devices, therefore they must have an adequate level of
immunity.
3.3.3
Disturbances are conventionally classified in low frequency (0 = < f < 9 kHz) and high
frequency ( f > 9 kHz).
Among phenomena at low frequency, phenomena at harmonic frequency of the frequency
of the net are particularly important.
Beside, there exist phenomena at wide spectrum, such as electrostatic discharges in air or for
contact.
3.3.4
Disturbances must be transmitted both through conductors (<conducted disturbances>;
conducted emission: 0,15 MHz
30 MHz) and by irradiation (<irradiated disturbances>;
÷
irradiated disturbances: 30 MHz
1000 MHz).
÷
3.3.5
Industrial experience has demonstrated that the main causes of lack of compatibility
are due to condueted disturbances.
3.3.6
The installation of the drive must be executed scrupulously following the instructions
contained in the paragraphs 3.1 and 3.2 of this chapter.
3.3.7
In view of electromagnetic compatibility, the installation must be carried out fulfilling some
suitable directions; here are the main ones.
Except some very special cases, the BHL-D convertor is assembled inside a metal cabin
(the so-called electric cabin), which also contains different electric equipment (other electronic
power convertors, contactors, transformers, impedances, etc ... ).
The "motor & sensors" (see paragraph 1.2.5), which includes beside a motor series 8 also
an angular position transducer RESOLVER, the motor thermal switch and, where required,
the brake, is normally assembled on the machine at some distance from the electric cabin.
Therefore, actually there exist two different types of plant: one refers to the manufacturing of
the electric cabin and one is the real "in situ" plant, which is reafized by the construction
electrician at the final customer.
3.3.8 Electric cabin
In view of EMC, some important prescriptions must be considered in the electric cabin; they
are related in the following paragraphs.
MANIU04.9607 GB 03/97
Page 3.10
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