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ELECTRICAL INSTALLATION
WARNING. Whenever wiring is to be done to the terminal strip of the detector, make sure ALL sources of
power have been disconnected. Terminals controlling other devices may be powered from sources other than
those supplying the metal detector. Caution should be used when working on machinery as components may
stop and start automatically without warning.
The metal detector operates from a single phase, 60Hz supply, 10%.
Use a power feed that is free of motor start-up transients or other interference. A dedicated circuit is
recommended but not required as long as the power feed is “clean."
If the metal detector is supplied with a conveyor, they should have separate power cords, even if the detector
and conveyor require the same voltage. Start-up transients from the conveyor motor could cause interference or
even damage the metal detector.
All power supply grounds for the detector, conveyor, and reject devices must originate from a single point. All
metal detectors require a good power ground. A good ground helps drain off “noise” that can be on the AC
power. Many plants use “conduit” grounding. This is not acceptable because of the possibility of loose
connections that can become open connections and cause the ground to “float”. The power feed to the metal
detector must have a dedicated third wire ground. Multiple grounds should be avoided.
Electrical connections to the metal detector are made via a terminal strip housed inside of the separate “power
box”. A terminal connections chart is located on page 5 and on the inside of the power box cover.
Main power is applied to the metal detector via Terminals L IN, N IN, and G IN. The remaining terminals are
used to wire conveyor stops, reject devices, and alarm systems.
A SPECIAL NOTE ABOUT VARIABLE FREQUENCY DRIVES (VFD) OR INVERTERS:
Variable frequency drives (VFD) are a major source of radio frequency (RF) interference. It can be radiated
through the air, through the power feed, and also through the ground connection. The RF interference can
prevent the metal detector from operating at its maximum sensitivity. The makers of the drives also sell filters
that can help minimize the RF interference. They should be purchased and installed according to the
manufacturer’s instructions.
In general, the following is recommended for VFD’s.
Always purchase and install the manufacturer’s filters.
Never run the VFD’s power lines and the metal detector power lines in the same conduit or cable trough.
Keep all VFD wiring as far away as possible from the metal detector.
Use shielded cables whenever possible and make sure the shield is grounded.
The VFD, motor, conveyor, etc. should have one grounding point.
OTHER POSSIBLES SOURCES OF METAL DETECTOR INTERFERENCE
A large part of any metal detector is its main receiving antenna. Any equipment that emits, or radiates, a signal
that can be picked up by the receiving antenna can cause a false trigger in the metal detector. Possible sources
are; other metal detectors operating at or near the same frequency, induction cap sealers, large motors, and any
ungrounded equipment.
