Sunday, June 3, 2012

Alternating & Duplexing Relays,Duplex Panel with Latching Pump Down Operation,Timer Replaces Expensive Float Switch,Pump Contactor Auxiliary Contacts,

Alternating & Duplexing Relays
Power must be applied at all times. When the level in the tank rises to the normal level, the Lead Float Switch closes. Pump "A" is turned on via Pump "A" contactor, and will remain in this condition until the Lead Float Switch opens. When the Lead Float Switch opens, the ARP relay contacts transfer. When the level in the tank rises again to the normal level, the Lead Float Switch closes, energizing Pump "B" via Pump "B" contactor. Pump "B" will remain energized until the Lead Float Switch opens. The ARP relay contacts then transfer back to their original position. The ARP's internal relay contacts transfer each time the Lead Float Switch opens. By alternating the lead pump for each successive operation, the total number of operating hours is similar.
Typical Connection Diagram for Alternating Relay
When an Alternating Relay is internally cross wired, the normal alternating operation is extended to include duplexing. If the Lead Float Switch cycles as previously explained, normal alternating operation will occur. If the Lead Float Switch and the Lag Float Switch close simultaneously, due to a heavy flow into the tank, both pumps A & B will be energized. The ability to alternate the pumps during normal work loads and then operate both when the load is high is called Duplexing. Duplexing relays can save energy in most systems because only one smaller pump is operating most of the time; yet the system has the capacity to handle twice the load.
Timing Diagram for Duplexing Relay
Duplex Panel with Latching Pump Down Operation
Many dual pump, duplex pumping applications, require two or more float switches to properly operate the system. The ARP Series of alternating (duplex or cross wired) relays are designed to equalize run time for two loads by automatically changing the "lead pump" and "lag pump" sequence at the end of each cycle. The ARP assures approximately equal wear on both loads, plus the duplexing models allow both pumps to operate simultaneously. This application can be used for water and wastewater pumping; and for circulating and distribution pumping of various liquids.
The diagram depicts a typical drain pumping application. The OFF, Lead and Lag float switches are connected as shown. As the liquid level rises, first the OFF and then the lead float switches close; pump "1" energizes. The liquid is pumped down by pump "1" until the OFF switch opens because of the latching action of the P1 auxiliary contacts on the pumps contactor. As the OFF switch opens, pump "1" turns OFF and the ARP toggles making pump "2" the lead pump. This operation continues with the pumps alternating lead/lag order on each successive cycle. If the flow is too heavy for one pump, the lag float switch eventually closes. Now, both pumps operate until the OFF float switch opens. A benefit of this connection method is the elimination of rapid cycling of the pump motors caused by float switch bounce.
Duplex Panel with Latching Pump Down Operation
Timer Replaces Expensive Float Switch
In this application, a TDM delay on make time delay replaces the OFF float switch. In a duplexing pump controller, an OFF switch is installed at a level below the Lead Float Switch. The lead pump starts when the Lead Float Switch closes, and stops when the OFF switch opens. The difference in the position of the switches produces a time delay that prevents rapid cycling of the pump. Because of the installation and maintenance expense associated with all float switches, this solution replaces the OFF float switch with a no maintenance TDM time delay relay.
In the figure when the input flow exceeds the capacity of a single pump, both pumps operate. Unless the lag pumps contactor is latched ON, the lead pump will operate continuously and the lag pump will cycle ON and OFF as the lag switch opens and recloses. Remember the lag switch only closes when the fill rate exceeds the capacity of the lead pump. As the Lag Float Switch opens, the lag pump is turned OFF. Because of peak flow, the level immediately rises and turns the lag pump back ON; rapid cycling it.
Operation with the time delay installed:
The diagram is shown with the Lead Float Switch already closed. Pump A (lead pump) does not start until the TDM delay on make timer energizes. When the TDM energizes, relay contacts 1 to 3 and 8 to 6 close energizing pump A. The TDM remains energized until the Lead Float Switch opens. When the level rises and closes the Lag Float Switch, the lag pump (pump B) energizes immediately. Pump Contactor Auxiliary Contacts, PC A and PC B latch the lag pump on. Both pumps operate until the Lead Float Switch opens; the TDM de-energizes and the contactor's auxiliary contacts open. The ARP duplexing relay transfers to position B, making pump B the lead pump for the next cycle. Typically, the level rises again, re-closing the Lead Float Switch. The lead pump does not restart again until the TDM time delay times out. The TDM prevents rapid cycling of the lead pump by providing the time delay typically created by the OFF and Lead Float Switches; at a fraction of the cost.
Operation with the time delay installed


  1. This is a good tip especially to those new to the blogosphere.

    Brief but very precise info… Thank you for sharing this one.
    A must read article!

    Stop by my page ::

  2. Thank you a lot for sharing this with all folks you actually
    know what you are talking approximately! Bookmarked.

    Kindly also consult with my site =). We will have a hyperlink trade contract among us

    Look into my blog post ...

  3. Hello to every single one, it's in fact a nice for me to pay a visit this website, it contains helpful Information.

    Also visit my page - porn star

  4. A person essentially assist to make severely posts I would state.
    That is the first time I frequented your website page and up to
    now? I amazed with the research you made to create this particular submit extraordinary.

    Great process!

    My page ... please click the following internet site -

  5. At this time it appears like Expression Engine is the preferred blogging platform available right now.

    (from what I've read) Is that what you are using on your blog?

    Take a look at my webpage :: link

  6. Superb, what a website it is! This web site presents helpful facts to us, keep it up.

    Check out my web-site ::

  7. Hi! Do you use Twitter? I'd like to follow you if that would be okay. I'm
    definitely enjoying your blog and look forward to new updates.

    my web page: he has a good point

  8. Have you ever thought about adding a little bit more than just your articles?
    I mean, what you say is valuable and everything. However think of if you added some great graphics or videos to give your posts more, "pop"!
    Your content is excellent but with pics and clips, this blog could definitely
    be one of the very best in its niche. Awesome blog!

    my web-site visit website

  9. Hello i am kavin, its my first occasion to commenting anywhere, when i read this post i thought i could also make
    comment due to this sensible article.

    my web site - more

  10. Very good post! We are linking to this particularly great post on our website.
    Keep up the good writing.

    Visit my website Air Max

  11. Good day! This post couldn't be written any better! Reading this post reminds me of my old room mate! He always kept chatting about this. I will forward this article to him. Pretty sure he will have a good read. Many thanks for sharing!

    Have a look at my weblog :: in porn photo

  12. I'll immediately clutch your rss feed as I can not find your e-mail subscription hyperlink or e-newsletter service. Do you have any? Kindly permit me understand in order that I may subscribe. Thanks.

    Here is my web site :: Additional Hints

  13. What you said made a ton of sense. However, what about this?

    what if you were to create a killer title? I ain't saying your information isn't solid.

    , however suppose you added something that makes people desire more?
    I mean "Alternating & Duplexing Relays,Duplex Panel with Latching Pump Down Operation,Timer Replaces Expensive Float Switch,Pump Contactor Auxiliary Contacts," is kinda vanilla.

    You ought to peek at Yahoo's front page and watch how they create article headlines to get people interested. You might add a related video or a pic or two to grab people excited about everything've written.
    Just my opinion, it would make your website a little livelier.

    Take a look at my weblog: a porn photo

  14. constantly i used to read smaller content which as well clear
    their motive, and that is also happening with this article which I am reading at
    this place.

    Have a look at my homepage ::

  15. This comment has been removed by the author.

  16. Formіdable post : pérennisez de cette façon

    Feel free to surf to my websіte; video de sexe gratuite