# What is relay timer? **URL:** \ **Category:** Industrial Automation\ **Created:** [March 15, 2016, 3:35am UTC](https://forumautomation.com/t/what-is-relay-timer/861 "2016-03-15T03:35:31Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![denizen](https://forumautomation.com/letter_avatar_proxy/v4/letter/d/848f3c/32.png) [@denizen](https://forumautomation.com/u/denizen)\ **Post date:** [March 15, 2016, 3:35am UTC](https://forumautomation.com/t/what-is-relay-timer/861/1 "2016-03-15T03:35:32Z")
**Relay Timers** Timing relay has device that delays the immediate activation or deactivation of the armature when power is applied to or removed from the relay (or both) Older units used pneumatic/fluid cylinder or motor/gear arrangements. New styles uses electronics,R/C network to generate delay. Timing relay contacts are - a)Specified by style of contact -Normally open -Or Normally closed b)Specified by delay operation -timed closing -Timed opening ![timer relay - types and categories](https://cdn.forumautomation.com/original/1X/731b0948c00ecbf25efeb8e0f61e18e710dce2b3.jpg) **NOTC (Normally Open,Timed Close)** The direction of the contacts motion is identical to regular NO contact,but there is a delay in closing contact. Contacts are open before coil is energized,timing occurs when coil is energized. This type of contact is alternatively known as a normally-open,on-delay. **NOTO (Normally Open,Timed-Open)** This type of contact is normally open when the coil is de-energized and closed by the application of power to the relay coil. The timing action occurs upon de-energization of coil rather than upon energization. Alternatively known as a normally-open,off-delay **NCTO (Normally closed,Timed Open)** Contact is normally closed when the coil is de-energized. Contact is opened after the coil has been continuously powered for the specified amount of time. Alternatively known as a normally-closed,on-delay. **NCTC (Normally Closed,Timed-Closed)** Contact is normally closed before the coil is energized,and opened by the application of power to the relay coil. The timing action occurs upon de-energization of the coil. Alternatively known as a normally-closed,off-delay.