Neuro-Audio (Technical Manual)
16
·
Place the electronic unit on the maximum possible distance from power cables,
switchboards, and different powerful electrical devices which can emit
electromagnetic fields of mains frequency.
Requirements to mains:
·
The system should be supplied from 230 V mains equipped with TN-S or TN-C-S
ground system (according to IEC 60364-1).
·
To avoid the risk of electric shock, this equipment must only be connected
to supply mains with protective earth.
·
Before setting of the digital system, the quality of standard tripolar sockets
and the integrity of protective ground circuit must be checked
by the electrician. For more details see section 2.3 “Reducing Electrical
Noise”.
·
In case the system components are connected to several tripolar sockets,
make sure they are grounded to one and the same protective ground circuit.
Otherwise, there is a danger of compensating current leakage (several tens
of amperes) through the system connecting cables that leads
to the equipment break-down.
2.3. Reducing Electrical Noise
There are some factors that may impact ABR test results. They are the electrodes
placement and its impedance, patient’s condition, ambient noise. However,
the electrical interference is the most important factor that can worsen the result
greatly. The information concerning the electrical interference reduction is given in this
section.
Grounding is crucial for the good ABR recording and safe operation.
The power cord contains a ground lead (typically indicated by yellow and green
colours), but often the ground at the test site may not be sufficient.
In such cases follow these recommendations.
Ground the patient bed if it is made of metal.
Turn off all other electrical equipment not used in the room
, especially
the sources with neon lights.
In some cases, it may be necessary to find another room for testing if there is too
much ambient or electrical noise.
You can also try to move a test site within the room as the patient might be near
the power cord (or a kind of that) hidden in the wall close to the patient and
electrodes.