What is Sequence On – Simultaneous Off Operation on Pump Control?

Monday: March 13, 2017 : Alternating Relays


Issue:

I want my two loads to come on one after the other, but then both loads to stay on together until the last control switch is opened.

Solution/Resolution:

The diagram illustrates a type of operation known as “Sequence On - Simultaneously Off (S.O.S.O.)”- the two loads are energized sequentially, but remain on together until the OFF switch is opened. This operation works best when using a DPDT Cross-Wired Alternating Relay.

In the initial OFF state, all three switches are open, the Alternating Relay is in the LOAD 1 position, and both loads are off.  No action happens with the Alternating Relay or either load when the OFF switch closes. When the LEAD Switch closes, LOAD 1 turns on.  When the LAG Switch closes, LOAD 2 turns on.  Both loads remain on as long as all three switches are closed. When the LAG Switch opens, LOAD 2 remains on because the OFF Switch is still closed and auxiliary contact M2 is still closed. When the LEAD Switch opens, LOAD 1 remains on because the OFF Switch is still closed and auxiliary contact M1 is still closed. When the OFF Switch opens, both LOAD 1 and LOAD 2 are turned off simultaneously because all voltage is removed to both loads. Auxiliary contacts M1 & M2 both open. The Alternating Relay toggles to the LOAD 2 position. The entire cycle is then repeated, but with LOAD 2 energized first followed by LOAD 1.

For more information, please contact Macromatic at 800-238-7474.

 

©2018 Macromatic Industrial Controls, Inc.

W134N5345 Campbell Drive
Menomonee Falls, WI 53051

800-238-7474 • 262-781-3366

Rep Login | Newsletter Sign Up | Articles | Employment | Privacy Policy | Sitemap
Knowledgebase General | Alternating Relays | Current Sensing Relays | Liquid Level Control Relays | Seal Leak Relays | Three-Phase Monitor Relays | Time Delay Relays | Voltage Monitor Relays