Relay
Wiring An End-Of-Line Power Supervision Relay on 4-Wire Smoke Detector
What is a 4-Wire Smoke Detector and why do I need a Relay?
A 4-wire smoke detector uses 4 wires to operate. 2 wires are utilized for power and 2 wires are used as initiation circuit. Most modern 4-wire smoke detectors use a wiring base and a smoke head that is installed on the wiring / mounting base.
Elevator Shunt Trip Wiring
Elevator mechanical rooms protected by a sprinkler may require an Elevator Power Shunt Trip device. The drawing below is an example of a shunt trip system. In this example, we are using a 135-degree fixed dual-terminal heat detector. The fire alarm system monitors one side of the detector, while the other side is used to pass line voltage to a Shunt Trip Power Disconnect Device. When the heat detector trips, power from the shunt trip power circuit is passed to the shunt trip device, which trips, thereby removing power to the elevator system.
Wiring HVAC Shutdown Using Fire System Relay With High Current Relay
When a fire alarm occurs it is common to shut down HVAC equipment to control the spread of smoke and fire. In some cases, positive pressure fans are turned on to create a high-pressure area in stairwells which keeps smoke out. Smoke and Fire Dampers are very common in modern construction and they must close in case of fire.
Wire Elevator Shunt Trip and Shunt Trip Power Supervision
When fire system sprinklers are located where elevator equipment is located it is common to install a Shunt Trip. The shunt trip removes power from equipment BEFORE water is to flow on equipment. This prevents shock and prevents further use of the elevator. The shunt trip is triggered by a heat detector located within 18" of a sprinkler head and is intended to trip before the sprinkler head.
Wire Access Control with ADA openers using a BR-3
Access Control with ADA Buttons using BR-3 Relay Module
This method assumes the door opener does not have programmable inputs and outputs thereby using the BR-3 module to provide the delay between door unlock and door open, OR you do not have the ability to program the door opener, OR you don't want to mess with another trades equipment. The desing below is shown with all ADA buttons being hardwired.
Wire Access Control with ADA openers and High In-Rush Power Supply for ELR Exit device
In some commercial applications, you may come across installations where the door latch requires a power supply that provides greater inrush (start-up) current than a normal power supply can provide or within the amp ratings of the access controller. Often these power supplies are located within 10-30 feet of the door and require a dry contact closure to trigger the power supply.