Haltech E6S - Manual (Page 120)

120
There a two types of hall effect sensors available from Haltech
THE S1 HALL EFFECT SENSOR
The S1 sensor which is identified by a black cable gland and operates in the following way:
As a south pole passes the sensor face the signal in both the primary (PIN C) and secondary
(PIN D) channels are switched to a low state. As a north pole passes the sensor a low state
will only occur on the primary channel.
N.B. MAGNETS SHOULD ALWAYS BE MOUNTED IN A NON FERROUS
MATERIAL SUCH AS ALUMINIUM .
With these characteristics a direct fire can be set up in the following way:
USING THE SENSOR ON THE CRANK
After a suitable mounting location for the sensor has been found the engine should be
positioned at approximately 75
°
BTDC cylinder no.1 compression. The magnet should now be
placed in the aluminium disk with the south pole facing towards the sensor, making sure the
magnet is in line with the sensor when the engine is in this position. This is now the reference
point for all the other magnets. The number of cylinders will determine the number of
magnets required and the angle of installation. The remainder of the magnets to be fitted will
all have a north pole facing the sensor.
The adjustment of the air gap will be determined by the strength of the magnets used. This
should be tested once the wheel assembly has been installed. Checking the Engine Data page
for steady RPM is usually a good indication that the airgap is acceptable.
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 strongly recommend that Haltech rare earth magnets (part number REM1) be used for the
purpose of triggering the sensor. These are strong magnets 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.