A relay is a switch that will open or close a circuit. They come in many shapes and sizes but they all do the same thing.
Relays come in two forms "wet" or "dry". Wet means that voltage is already there in the relay. You may never see or come across this type of relay in the types of jobs we do. Dry means that it has no voltage and you will have to bring voltage to it. This is the most common type of relay in use today.
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| A dry relay is what is used in the Linear LED 67 receiver to remotely unlock a door. You will need to bring voltage to power the unit as well as voltage to the relay. Then connect the relay as an open or closed circuit. This is required when you wire the Secura Key 26SA card reader to operate the lock you are installing.
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The relay will come with three terminals: labeled as common (C), normally open (NO) and normally closed (NC). This tells you what state the relay is in when not in use. This state will change when voltage is applied to the relay. When installing an electric release that is Fail Safe you would wire the relay with one wire to common (C) and one to the normally |
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(NC) terminal of the relay. This way if the relay looses voltage it will cause the release to open or unlock the door.
Relays come in two common voltages, 12 or 24 volts A/C or D/C. Not all relays work with a combination of 12/24 volts. You will need to know what voltage you are working with. |
A good example of how a relay works is with the Securitron BPS power supply. When the power supply looses 110 volts A/C the relay closes and allows the unit to run on battery back up. This way the lock still works and the building will remain secured. |
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