Everything You Need to Know About Timer Relay

The majority of electricians are familiar with the concept of a time relay. In the energy industry, it is very popular and well-known equipment. Since 1968, Time Relay has been known for its dependable designs that offer long service lives and low maintenance costs. Timer relays use a simple operating concept that allows you to select from various functions and time delay ranges to guarantee that you get the appropriate timer for your needs.

Continue reading to learn about the different types of timer relays, their applications, and how to choose the right one for you.

What is a Time Delay Relay?

Control relays having a built-in time delay function are called time delay relays. They manage an event by electrifying the secondary circuit after a set length of time or for a set time, or both.

When voltage is delivered to the coil on the primary side of a conventional normally open control relay, the contacts on the secondary side close instantaneously. When the primary side’s electricity is cut, the secondary side’s contacts open, cutting power to the load.

We don’t want an immediate answer from the secondary side for specific applications; instead, we want it to happen after a particular length of time or only for a limited time. A time delay relay can help us with this.

The delay on the type and the delay-off type are the two primary varieties of basic timing relays. We may regulate the delay time of these relays from milliseconds to hours or even days, and they can be normally open or normally closed.

How Does Time Delay Relay Work?

The working principle of the timer relay is electromagnetism. One relay coil is constantly on, while the other can be turned on and off using an electric signal from a control device like a phone or computer system. The “on” coil is constantly receiving electricity, allowing it to activate at any time.

When the device is triggered, the “off” coil receives power and works to pull in an armature, which activates the other end of the circuit, where electricity flows. This armature returns to its original position when the power is switched off, preventing electricity from flowing through the circuit

Types of timer relay

The system configuration determines the type of time delay relay that is utilized. The most common time delay relay timers used are on- and off-delay timers. Interval-on-operate, flasher, and repeat cycle clocks are examples of other types.

On-delay timers

When the input voltage (power) is applied, normally open, on-delay clocks begin timing. After the wait, the output is powered. The input voltage must be removed to de-energize the output and reset the time delay relay.

Blower motor delay timers, also known as delay-on-operate timers, are commonly used to postpone the operation of a gas, electric, or oil heater for a set time after it has been turned on. On-delay timers are also used to stagger the start timings of various compressors or motors controlled by the main switch.

This prevents the electrical cable from becoming overloaded by surge current. Burglary and intrusion alarms, open-door warnings, power supply sequencing, oven ignitor controls, and fan controls are just a few of the other applications.

Off-delay timers

When voltage is delivered to an off-delay timer, nothing happens—the contacts transfer when the control input (SW) is closed. The timing begins when the control input is opened, but the contacts stay closed.

When the countdown runs out, the contacts are transferred. The timing is reset when the control input is closed before the timer expires. The timing is reset, and the contacts are opened when the voltage is removed before the time-out.

On the other hand, accurate off-delay timers maintain contact closure even if the input voltage is lost. Even if the timer loses power, capacitors maintain the connections closed. On-delay and off-delay timers have unique contact symbols.

They are the only TDRs with specific contact symbols. Other TDRs use the same contact symbols as relays. A message is frequently written near the relay sign to indicate the functioning condition. With the voltage removed, the state of the relay contacts is always displayed.

Interval-on-operate

The output of interval-on timers, also known as one-shot timers, is energized when the input voltage is delivered and the time delay begins. After the delay period has passed, the output is de-energized. To reset the time delay relay, you must remove the input voltage.

Depending on the specific model selected, interval-on time delay relays can be utilized for various general-purpose and demanding industrial and commercial applications. Interval timers are used in specific burglar alarm systems. Other applications include timed cycles for electric welding machines, seat belt reminders in automobiles, dispensing equipment, and pump stations.

Flasher

The contacts activate and de-energize sequentially when a flasher receives an input voltage. On-cycle and off-cycle times are the same. Remove the voltage and then reapply it to reset the timer. Alarm systems, indication lights, warning light systems, and sequential timers, such as those used for airport runway illumination, are all typical uses for flasher timers.

Repeat cycle

Cycles can be adjusted individually using two settings on repeat cycle timers. As long as the voltage is provided to the time delay relay, these cycles will continue. Some repeat cycle timers start with the off-timer and work their way up to the on-timer. They could, for example, be used in tandem to turn on and off lamps.

Time Delay Devices

Thermostatic relay

One of the connections is a bimetallic element wrapped in an isolated heating coil in this variant of a time delay arrangement. The heating coil is given the signal strength. The delay time is the amount of time it takes to elevate the contact temperature to a point where deformation occurs, causing the contact to transfer.

Standard thermostatic time delay relays have a time tolerance (precise) of just 20%, although customized designs can have greater tolerances. These units are similarly only around 5% repeatable, but they are cheap and naturally resistant to transients.

Motor-Driven

Asynchronous motor is used to power this relay type. A basic train of machine-cut straight gears is used to propel a firing arm. The arm triggers a rapid action switch, with the delay period determined by the motor speed and gear reduction.

An electromagnetic coil clutches and disengages the trigger lock gear as needed, allowing the reset to happen instantly. A series of auxiliary contacts are frequently included with the clutch coil. The motor circuit receives power, whereas the clutch coil receives signal power.

The clutch coil controls the instance contacts, while the trip arm controls timed contacts. The delay in power interruption rises as clutch power is maintained. To put it another way, the relay accumulates as long as the motor is powered on until it reaches the predetermined time of the delay relay.

The use of an asynchronous motor ensures great precision and, when coupled with the suitable gear, allows for highly long delays of hundreds of hours. A progress indicator is sometimes included with these relays.

The Basics of Time Delay Relays

Time delay relays (TDRs) can provide simple, dependable, and cost-effective control in any situation where a definite-purpose solution is required. It’s often as easy as flipping a knob to change the delay time.

TDRs are primarily utilized in industrial applications and OEM equipment, providing time-delayed switching to start a motor, manage a load, or affect a process. They’re also helpful for specific logic requirements, such as small panels or sub-panels. Compactness, economy, simplicity, and ease-of-use are only a few of the qualities and operating characteristics.

When voltage is provided to the coil in a conventional control relay, contacts close immediately and open quickly. The action of the contacts should be delayed when voltage is applied or removed in a variety of applications. The problem is easily solved by using a TDR. Some TDRs, on the other hand, delay the closure of the contacts when voltage is applied, while others close them and then reopen them after a period.

Plug-in TDRs, like plug-in control relays, are available as plug-in devices. They are, however, available in a variety of alternative configurations, such as base-mounted devices and direct IEC DIN-mount controllers. On a motor starter, for example, a TDR can be installed.

The timing function in this application is started by turning on the motor starter; after the timing is complete, the device’s contacts operate. There are also electronic TDRs that can be installed on a starter. Instead of relay outputs, some TDRs use solid-state outputs.

TDRs used to come in single-function, single-time-range configurations exclusively. These devices are still available and are commonly utilized in situations where precision timing is required. TDRs with multiple timing ranges and functions are now commonplace.

These TDRs are less expensive than single-function devices and offer a wider control voltage range. In addition, newer multifunction IEC-style timers enable stocks to be decreased. Let’s look at a couple of the most frequent types of TDRs in greater detail.

Application of Time Delay Relay

Controlling power outlets

To turn the energy flow on and off, you can use two relays to regulate a power outlet. When you plug something into the outlet, one relay control turns on, while the other switches off once the gadget you’ve plugged in has finished charging or powering.

Activating lights

Turning lights on and off is a popular application for a relay with a timer. The procedure works by turning on the relay’s coil for a set time to activate it before turning off power flow so that lights can turn off after they’ve been turned on. If you want your lights to turn off automatically while no one is in the room, this is the way to go.

Controlling other types of machines

The time delay relay can be used to control various equipment powered by electricity. You could operate a piece of equipment in your homes, such as an air conditioner, heater, or home entertainment system, without having to travel across their living room. With the time delay relay, there are virtually limitless options for automation.

High-Performance applications

These devices are frequently encountered in high-performance applications that need precise timing activities, such as robotics or machinery. Activating valves in pneumatic cylinders, setting timers on coffee makers, lighting systems at airports and train stations, and even powering up surveillance cameras are just a few instances.

How to Test a Time Delay Relay?

There is a simple method for testing a time delay relay. First, ensure that the gadget is turned off and disconnected from the power source. Then buy an electric probe or any other electrical testing tool with two metal ends (one little and one large) that can touch your circuit board simultaneously. These probes should be linked so that each end goes into each side of the time delay relay “on” coil (the larger probe should be connected in between).

When electricity runs through wires and other conducting materials like metals, you will detect a back EMF if you do it correctly. When you move your probe from one coil to the next, you’ll notice a temporary reversal flow of electricity. If it does not appear, your time delay relay is either malfunctioning or has a damaged wire somewhere on its circuit board.

You can also check for continuity between either side of the “on” coil and ground with a multimeter. This should be represented by two probes touching at once. If there is no breakdown within the gadget itself, you will hear an audible sound. You can test each connection on both sides to see where it breaks and what needs to be fixed. This method also works with conventional relays; even though they don’t have coils like these, their internal switches must be properly linked for the gadget to function.

Conclusion

Time relays are versatile devices that can be utilized in various situations. They provide exact scheduling and delayed activation or deactivation of all types of electricity-powered machines. They’re also employed in high-performance applications that demand accurate timing, like robotics or equipment.

Give the time delay relay a try if you’re seeking a simple approach to automate your home or business activities. There is no need to create elaborate systems that require more than a few simple wiring and connections by using time delay relays. It’s simple to set up and may be used for nearly any purpose.

Lastly, for any electrical component question you have or intend to purchase, contact us at ICRFQ; we are the best electrical components manufacturer in China.