SENTROL Application notes - Alarms BC

......................................................................................................................................................................... Introduction
MOUNTING
Mounting Data for Steel Doors and Windows
The results of test runs in which Sentrol magnetic contacts were used on steel are
given here.
Test Procedure
Each sample was selected at random from finished goods inventory. Tests on each
contact were run to measure pull in (make), and drop out (break) distances prior to
mounting on the 6" wide, 16" long, and 1/2" thick steel plate.
Each contact pull in (make) gap distance was measured:
1. With contact and magnet attached directly to the 1/2" steel plate with no
spacers.
2. With a single, .125" spacer under both the contact and magnet. A 1/2" spacer
was used under both the magnet and contact in the 2505 test.
All measurements were recorded to the nearest 0.05" (fifty-thousandths of an
inch).
Test Results
All dimensions in inches.
Contacts mounted on 1/2”
Control tests in air
thick steel plate 6” X 16”
Sentrol A B Make Break
Switch Make Distance Make Distance Distance Distance
Number w/o spacer with spacer under Pull in Drop out
magnet & contact
1085T .4 .55 .8 1.0
1085-W .75 .95 1.5 2.1
1082T .55 .7 1.25 1.5
1084T .4 .6 1.0 1.2
1084T-W .9 1.2 2.3 2.55
2505 1.2 2.2 4.2
Conclusion
The Sentrol surface-mounted contacts should be satisfactory for applications in
such areas as steel fire doors, safes, file cabinets, truck doors, and roll-up garage
doors. Customers should be reminded to allow plenty of safety factor in
installation. Sentrol recommends installing the contact and magnet with no more
separation than about 50% of the pull in distance. For instance, on the Sentrol
1084TW measurements on steel, a maximum separation of 0.5" to 0.6" should
provide a reliable system.
Rules of Thumb
• Gap on steel is approximately half the distance achieved in air.
• Space switch and magnet at approximately 25% of rated gap in air for safety
factor.
• Use a spacer whenever it is practical. If only one spacer is used, mount it under
the magnet.
• Applications on steel do not “drain” the magnet, but they do reduce the
magnetic field.
MAGNETIC CONTACTS
3.8