Time Delay Relays Basics

What is a Time Delay Relay?

Much like a normal relay, time delay relays allow us to electrically control a switch. They still rely on a coil to become energized, and once the coil is energized, it will either open or close a switch depending on the type of relay being used. Time delay relays, however offer some additional functionality. They give us the ability to delay the on or off function of the contacts, which can help perform various functions that we see on a daily basis. Let’s talk about some of the most common types of Time Delay Relays, and why we might use them.

On Delay
On a normal relay, when the coil is energized, normally the contacts will close right away, allowing current to pass through. With an “On Delay” relay, when the coil is energized, the contacts will not close for a certain period of time. This delay can be configured in most time delay relays to certain allotted time the works best for our particular application.

Example: This is commonly used in situations where we might be powering two different devices, but don’t want both devices to energize at the same time due to the voltage spike. So for instance, if we have a motor we want to start, and a fan that needs to cool that motor, the delay on relay can be used to first power the motor, and then power on the fan once the motor is fully powered. This will reduce any power surge we might see.

Off Delay
This will operate in a similar fashion to the on delay relay, the main difference being that the delay will not occur until the coil is deenergized.

Examples: Garage door light. Motor and fan

On/Off delay Relays

Have the ability to perform the delay function when the coil is first energized and also when the coil is deenergized.
Example: My home table saw

Additional types of time relays
Beyond the few types of timers already mentioned in this article, additional types are available, such as:
- Flasher — When voltage is applied, the contacts energize and de-energize alternately. Timing action is halted by removing voltage from the coil. On and off cycle times are the same lengths.
- Repeat cycle — Operation is similar to the flasher, but the timing cycles are independently adjustable.

Many other types of time delay relays that can be used in many different applicatons.

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[AndrewOtwellMusic]

Excellent content and presenter. Thank you!

[chriscockrell]

Time delay
On delay relay. To reduce the inrush current. Fuse or breaker issue. delays the turn on
Off delay relay. Garage door opener light. The light stays on for a little. Or a fan on a saw. delays the turn off of a secondary device.

[clenlima]

Very good! I publish all day your channel.

[PBS-nmuu]

would be better if you showed what they looked like

[olaoluwadurotimidauda]

Require circuit connection from on and off delay relay

[lawrenceveinotte]

i want to set up a spot welder, i press down a momentary switch which powers the transformer, the transformer stays on for a number of milliseconds that i can set, then i let off the momentary switch and reapply the switch and it repeats the whole process, the transformer is 110 volts, i will set this up without the timer first it's just more consistent with a timer.

[collinswhite]

Thanks for the video. What time relay can be use to switch a circuit permanently after the coil of the time relay is deactivated but u want the contact still close after the absence of power at the coil

[saeed]

Why you didn’t mention the utilization to create an automatic looping when controlling devices.

[TheReildawg]

What provides the actual time delay? As in, what stops the contacts from moving immediately in a on-delay relay?

[techwizaman]

it is good but no circuit diagram shown just talking