Home Burglar Alarm Systems Often Contain Timer Relays
Home burglar alarm systems often contain time delay relays. This type of relay features a normally open (instant open on energizing) contact that closes after a pre-set time delay.
The delay can be adjusted via a pointer on the unit that shows you how much time has passed since the relay was last energized. It can also be set on and off for repeated cycles.
Using a Relay
Time delay relays are used to control devices that require power to be applied for a certain period of time before switching off. This can be useful in ensuring the device has enough time to turn off after it has been activated, for example, an outlet that you use to charge your phone or plug in a light bulb.
They work by introducing a timing element into the circuit and delaying when the relay contacts energize or de-energize. These are usually used in many types of equipment including air conditioning, electrical distribution and lighting controls to name a few.
There are many different types of timing functions that can be set on these modules and each one has its own specific purpose. Some of the most common include ON / OFF, ON / OFF + Timer, ON / OFF + Timer + Countdown, ON / ON + Timer.
The majority of these timer relays feature high side gate driver a dial for the time adjustment along with two small switches that allow you to change the time base between sec, min, and hrs. The dial also has a “stop” switch which allows you to stop the operation of the module and display OFF on the LED.
Using a relay with a timer is simple and involves connecting the output to the circuit you want to control. Once the input voltage is applied, the output of the relay will be energized and the timer will start counting down. Upon reaching the end of the timer function, the output will de-energize and the relay’s contacts will return to their original position.
Determining the Relay’s Delay
While a regular electromechanical relay is simply a switch that uses one level of voltage to control another, time delay relays have the ability to add in the element of time. These switches are designed to open or close after a set amount of time, and they can be used for many different applications. There are multiple kinds of timer relays available and they all operate differently, but the most common type is the on-delay or off-delay timer.
On-delay timers begin the timing cycle once they receive a trigger signal. This could be a dry-contact control switch, float switch or push button; or it may be a voltage input. Upon receiving the trigger, the output is energized and stays energized until the preset time period passes. If the trigger is continuously supplied with power at a rate faster than the preset delay time, the output will remain energized until the timer resets.
Off-delay timers, on the other hand, are not triggered by any external signal. They are triggered by a power supply, and the contact opens with the application of power to the coil. Then, the contact remains open until it is triggered again. This type of timer is often used for door locks that should wait a few seconds after power is applied to check that they are closed before locking them.
Testing a Relay
A good relay will switch on and off in the proper time to avoid damage or a short circuit. However, Logic Comparators like all parts of a car, they can go bad from age or abuse. Understanding how to test a relay can make the difference between staring hopelessly under the hood and uttering choice four-letter words, or determining what’s wrong and getting it fixed.
Start by assessing the current and voltage ratings. Generally, this information is available from the manufacturer’s data sheet or may be printed on the relay body itself. It’s also important to know what the pin configuration is; this will help you avoid testing random pins, which can lead to unpredictable results.
The next step is to use a multimeter to check the coil’s continuity. Put the meter in continuity test mode, then apply a rated voltage to the coil. The meter should display an indication of continuity, which means the coil is closed. The normally open and the normally closed contact should be closed with a resistance close to 0 ohms.
Finally, it’s important to assess the voltage across the load terminals. This should be close to the load power supply voltage with the SSR turned OFF. If not, the SSR is likely faulty and needs replacing. This is a common cause of battery drain, and you’ll want to replace it as soon as possible to avoid a dead or damaged car battery.
Resetting a Relay
Some types of time delay relays can be re-energized by applying voltage to the input or control contact. Others must have the input or control contact disconnected and then reapplied to activate them again. The differences between these various functions can become confusing, and it is best to only use these devices in their intended application.
Interval timers, bypass timing relays, interval delay timers, and delay on energization with instantaneous transfer timers are some of the more common forms of time delay relays. All of these work by delaying the application of current to a circuit until after a certain amount of time has elapsed. This can help ensure that a circuit is not activated accidentally and allow for time for a system to stabilize before activation.
Another type of time delay relay is the recycle timer, which is used to conserve energy by cycling a load on and off at set intervals. These are sometimes referred to as duty cycle or cycle timers. Recycle timers can be single-function or multi-function, and they can be a good choice for applications where it is important to minimize power consumption. In addition to these time delay relays, there are also a variety of other devices that can be used in conjunction with a timer to provide additional functionality. These can include things like LED indicator lights, acoustic alarms, and alarm horns.
