HBM T40 - Electrical Connection; General Connection Guidelines

17
T40
HBMA24633.0en/de
4 Electrical connection
4.1 General hints
To make the electrical connection between the torque transducer 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
minimum 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
circuits. If this cannot be avoided (in cable pits, for example), maintain a
minimum 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 plugs attached 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 b ecome concealed. If this is
the case, it is essential for the cables to be relabeled!
4.2 Shielding design
The cable shield 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
rotor from electromagnetic interference.
In the case of interference due to potential differences (compensating
currents), supply voltage 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
2
wire
crosssection).
If potential differences arise between the rotor and the stator on the machine,
perhaps due to unchecked leakage, and this causes interference, it can