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5
Electrical connection
5.1 General hints
To make the electrical connection between the torque flange and the amplifier,
we recommend using shielded, low−capacitance measurement cables from
HBM.
With cable extensions, make sure that there is a proper connection with mini
mum contact resistance and good insulation. All plug connections or swivel
nuts nuts must be fully tightened.
Do not route the measurement cables parallel to power lines and control cir
cuits. If this cannot be avoided (in cable pits, for example), maintain a mini
mum distance of 50 cm and also draw the measurement cable into a steel
tube.
Avoid transformers, motors, contactors, thyristor controls and similar stray−
field sources.
CAUTION
Transducer connection cables from HBM with attached connectors are
identified in accordance with their intended purpose (Md or n). When
cables are shortened, inserted into cable ducts or installed in control
cabinets, this identification can get lost or become concealed. If this is
the case, it is essential for the cables to be re−labeled!
5.2 Shielding design
The cable shielding is connected in accordance with the Greenline concept.
This encloses the measurement system (without a rotor) in a Faraday cage. It
is important that the shield is laid flat on the housing ground at both ends of
the cable. Any electromagnetic interference active here does not affect the
measurement signal. Special electronic coding methods are used to protect
the purely digital signal transmission between the transmitter head and the ro
tor from electromagnetic interference.
In the case of interference due to potential differences (compensating cur
rents), operatingvoltage zero and housing ground must be disconnected on
the amplifier and a potential equalization line established between the stator
housing and the amplifier housing (copper conductor, 10mm
tion).
If potential differences arise between the rotor and the stator on the machine,
perhaps due to unchecked leakage, and this causes interference, it can usu
HBM
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wire crosssec
A2037−4.0 en
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