Ceia THS/MS21 - Conveyor Belt Motors; Ground Loops

3
FI002K0018v1100UK – THS/21 Instruction manual for installation, use and maintenance
INSTALLATION
56 ORIGINAL INSTRUCTIONS
3.1.3.3 Ground loops
Ground loops are unwanted or uncontrolled currents along the earth connection, which can
interfere with the functioning of the Metal Detector.
- Keep the Metal Detector antenna insulated from the load-bearing structure and from other
metal structures or conductors. For Metal Detectors not integrated in CEIA systems, refer to
the section on Mechanical Installation in the Metal Detector Installation Manual.
- Keep the load-bearing structure of the Metal Detector insulated from other metal structures
or conductors.
- Use an earth connection for the Metal Detector,
which comes directly from the electricity supply
board.
QE: electricity supply board; M1: machine 1
M2: machine 2; MD: Metal Detector.
QE M1 M2 MD
POWER BOX
- Connect the motors driven by the inverter (of the Metal Detector transport system and near
it) using screened triphase+earth cable: the frame of the motor and the screen must be
connected only to the PE terminal of the inverter.
- Provide the connection cable to the motor with a ferrite to be placed near the inverter,
passing one or more coils of the phase conductors through the ferrite itself.
- Prevent electric motors driven by the inverter (placed near the Metal Detector) from having
the frame connected electrically to the load-bearing metal structure.
- The metal frames of the input devices connected to the Metal Detector (e.g. encoder) and
the screens of the corresponding connection cables must be insulated from the fastening
structure.
- The signals connected to the Metal Detector inputs must be insulated from the earth
connection of the machine which generates them.
- Drive the Metal Detector inputs using relays.
IMPORTANT: Do not connect the Metal Detector antenna to earth because this is already earthed over the connecting
cable to the power supply.
3.1.3.4 Conveyor belt motors
The motors must be located at a distance D from the probe,
adopting measures identical to those described for the rollers
above.
Fit electrical motors with special metal screens and mains filters of
sufficient capacity. It is recommended that AC motors be used
rather than DC motors. The table below provides some general
guidelines for the distances to be placed between the probe and
asynchronous motors, depending on their power.
Minimum distance advisable between the probe and AC motors (without
motor screening)
Power All models THS/MN21
0.5 CV
3 DH5 DH
1 CV
4 DH6 DH
Motors
C: non-insulated support;
I: insulated support;
S: screening
The distances shown in the table are assessed with the default settings of the Metal Detector and with sensitivity of 280;
they can therefore vary according to the model, the dimensions and the actual settings of the Metal Detector.
This distance is indicative and also depends on the load conditions and the size of the probe.
The Customer is responsible for checking that the motor installed is actually compatible with the system.