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be set from 0 seconds (no startup delay) to 30
seconds by rotating a small control on the printed
circuit board. This feature is not normally needed
for overspeed detection, and may be removed by
rotating the control to 0 seconds.
Some equipment may require more than 30
seconds to get to minimum operating speed. For
those applications, speed sensors with longer startup
delays are available. Consult the factory for details.
4.0 MECHANICAL INSTALLATION
4.1
Mark Placement
The placement of the mark and sense head is the
main concern during installation. The face of the
mark must pass parallel to the face of the sense
head, and the center of the mark must pass through
the centerline of the sense head. There should be no
more than 3/4" between the sense head and the
mark, and 1/2" spacing is preferred. The mark must
move at least 6" away from the sense head during
operation, and in the case of multiple marks, they
must be separated by a minimum of 6", and they
must be exactly the same distance from each other.
A typical installation on a conveyor belt system
would monitor tail or idler pulley speed, and would
preferably monitor a fixed pulley with little end
play.
For a single mark installation, locate the edge of
the mark at least 3" from the center of the shaft.
Mount the mark by drilling and tapping two holes
on 1.56" centers, and use two bolts and lockwashers
to secure the mark. For a two-mark installation, the
marks must be at least 3" from the center of the
shaft, and exactly opposite each other.
One way to ensure proper mark placement is to
scribe a circle on the pulley by holding a piece of
chalk or other marker against the pulley at least 3"
from the center of the shaft, then rotating the pulley
through one full revolution. For multiple mark
installations, scribe a straight line from the center of
the shaft to the outer edge of the pulley and install
the first mark where the circle and line intersect.
Measure the circumference of the pulley, divide by
the number of marks, and scribe a line on the
circumference at that measurement. Then scribe a
line from that measurement to the center of the
shaft. Mount the second mark at the intersection of
the circle and the new line. For example, for a 6
mark installation on a pulley with a 42"
circumference, draw a line every 7" (42/6=7) on the
circumference, then draw 6 lines, one from each 7"
line to the center of the pulley. Scribe a circle of
appropriate diameter (See Table, below), then
mount one mark at the intersection of each radial
line and the circle.
Number of
Marks
Min. Mark
path Dia
Number of
Marks
Min. Mark
path Dia
1
6”
6
12”
2
6”
7
14”
3
7”
8
16”
4
9”
9
18”
5
11”
10
20”
4.2
PLACEMENT OF THE SENSE HEAD
A bracket must be fashioned to support the sense
head directly over the mark path. The sense head
face must be essentially parallel to the mark face,
and no more than 3/4" from the mark face (1/2"
preferred). If the mark pulley is moveable, be sure
that the sense head mounting moves with the pulley.
Check any end play in the pulley, and verify that the
mark cannot come in contact with the sense head
and cannot move more than 3/4" from the sense
head. The sense head mounting should be as free as
practical from vibration, easily accessible for sense
head servicing or replacement, and as protected as
possible from falling material.
The standard sense head cable is 10 feet long, so
if possible, mount the sense head within that
distance from the control board. If that is not
possible, the sense head can be mounted as far as
1500 feet from the control, and shielded cable
(Belden 8790 or equivalent) may be used to
interconnect the sense head and control board. A
junction box is available to connect the extension
cable to the sense head cable. In any case, the sense
head cable (and extension cable, if used) should be
run in a separate conduit, with no other wiring in
the conduit. In installations using multiple sense
heads, you may route multiple sense head cables in
the same conduit. If possible, route the sense head
cable conduit into the bottom of the control box.
Longer sense head cables of reasonable length
(up to 100 feet) are available on a special-order
