Haltech S4 Hall Effect Sensor - Manual (Page 3)

Identifying the magnets poles
If you need to identify the magnet poles this can be done easily with the use of a
multimeter. By powering up the sensor, using 12 volts (PIN B) and ground (PIN A)
the secondary trigger channel (PIN D) can be checked to identify a south pole.
Connecting the multimeter between PIN D and ground, 12 volts should be present.
When a South pole is placed in front of the sensor this value will go to 0 volts.
Fitting the magnets
We insist that only Haltech rare earth magnets (part number REM1) be used for
the
purpose of triggering the sensor. Rare earth magnets purchased from your local
electronics store may be less expensive but they are not good enough! Haltech rare
earth magnets are strong with good stability to reasonably high temperatures and
which have a long service life. Some rare earth magnets are stronger but break down
under excessive temperature, or are too brittle for the purpose, or do not have a long
service life. Ordinary magnets ie not rare earth types, may not have the strength
required for satisfactory triggering at high speeds.
Haltech REM1 rare earth magnets are normally 5mm dia x 2mm depth, although other
sizes are available upon special order.
The magnets should be fitted in non -ferrous surrounds such as aluminium, stainless
steel or titanium. The trigger wheel is normally made of the chosen material but
various users have reported good results when the magnets are set in a suitable non -
ferrous surround and the surround is set into a ferrous material.
The magnets should be set flush w ith or slightly back from the surface of the trigger
wheel or surround. If set too far back the magnetic signal may be too weak. The
magnets should be set in place with a strong and durable fixing compound such as
high strength epoxy, Loctite stud locking compound eg 603, or JBweld. Some users
rely only on the fixing compound but to ensure that the magnets remain in place but
many prefer that they be retained by mechanical means such as peening, and this
gives an added safety factor.
WARNING:
RARE EARTH MAGNETS ARE EASILY DAM AGED AND THE
PEENING PROCESS (OR LOCATION BY GRUB SCR EWS
ETC) SHOULD BE VERY CAREFULLY CARRIED OUT SO AS
NOT TO DAMAGE THE MA GNETS. IF DAMAGED THEY
WILL NOT HAVE SUFFIC IENT MAGNETIC STRENGTH OR
MAY FAIL MAGNETICALL Y OR PHYSICALLY AFTER A
PERIOD OF TIME.
If installed correctly the magnets will have a long life.