Class Notes - Year 4 - 2020-2021
Share
Explore
Year 4

Lesson 406

Timing Relays: Off-Delay, One-Shot, and Multifunction

IEC Manual 406

Abbreviations

NOTC
Normally Open Timed Closed
image.png
NOTO
Normally Closed Timed Open
image.png

On-Delay Timing Relay

When power is applied, time delay beings
At end of time delay, contacts energize
Remains energized until power is removed
image.png

Interval Timing Relay

When power is applied, contacts energize and time delay begins
At end of time delay, contacts de-energize
Resets when power is removed
image.png

Recycle Timing Relay

When power is applied, T1 off-time begins
At end of T1 off-time, contacts energize and T2 on-time begins
At end of T2 on-time, contacts de-energize and T1 off-time begins again
Repeats until power is removed
Some recycle times can have different T1 and T2 intervals
image.png

Off-Delay Timing Relay

Requires constant control power
When power is applied to initiating contact, output contacts energize
Removing power from initiating contact begins time delay
If power is reapplied to initiating contact during time delay, the sequence restarts
At end of time delay, output contacts de-energize
image.png

One-Shot Timing Relay

Requires constant control power
When power is applied to initiating contact, output contacts energize and time delay begins
Can be momentary power, as little as 40 ms
If power is applied again to the initiating contact during time delay, sequence
does not
restart
At end of time delay, output contacts de-energize
image.png

Operation of Off-Delay Timers

11-pin DPDT
image.png
8-pin SPST
image.png

Operation of One-Shot Timers

Operation of Multifunction Timers

Set time for 27 seconds
Square D
image.png
Set dial to 99.9S
Set numbers to 270
SSAC
image.png
Set SEC/MIN switch to SEC
Set x1 switch to on
Set dial for 27
Set time for 13 minutes
Square D
Set dial to 999S
Set numbers to 780
SSAC
Set SEC/MIN to SEC
Set X10 switch to on
Set dial for 78

Interval Timing Relay


Share
 
Want to print your doc?
This is not the way.
Try clicking the ⋯ next to your doc name or using a keyboard shortcut (
CtrlP
) instead.