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Mounting Data for Steel Doors and Windows

Edwards Signaling 9/28/2018
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 Interlogix 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" thick steel plate 6" X 16" Control tests in air
Sentrol Switch Number (A) Make Distance w/o spacer (B) Make Distance with spacer under magnet & contact Make Distance Pull in Break Distance Drop out
1085T 0.4 0.55 0.8 1
1085W 0.75 0.95 1.5 2.1
1082T 0.55 0.7 1.25 1.5
1084T 0.4 0.6 1 1.2
1084TW 0.9 1.2 2.3 2.55

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.