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  1. jaydub
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    jaydub Regular EF Member

    Location:
    Suffolk
    Hi guys, I have very limited experience with starters and contactors as my work has always been domestic and have not once come across either that I've needed to work on. Until now...

    I have been asked if I can update a swimming pool control panel and I think I have the general idea but am lacking some vital knowledge.

    At the moment a 16A timer controls a DOL starter which operates a 870W pump/motor.

    My idea is to replace this with a new single phase consumer unit, in which will sit a digital 16A timer, which will control a 20A contactor which will then operate the pump. Can I do it this way? Or does the contactor ideally need to control a DOL starter?

    Does a starter contain a contactor anyway? Do I need to think about thermal overload here as I don't believe a contactor will have thermal overload...

    There is also, I believe, an auxillary contact when the DOL starter starts that power a switched live that powers a pump-interlock for the pool heater. Could this simply be connected to the load side of the timer the same as the switched live to contactor?

    InkedPool panel_LI.jpg
     
  2. jaydub
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    jaydub Regular EF Member

    Location:
    Suffolk
    The filter needs to have manual override and is all single phase.

    Thanks
     
  3. ipf
    Online

    ipf Trusted Advisor

    A dol starter IS a controlled contactor, with overload.
     
  4. jaydub
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    jaydub Regular EF Member

    Location:
    Suffolk
    Thank you for clarifying that ipf, it is very much appreciated. I think that pretty much solves my confusion.

    Top left is the 16A feed into the contactor

    Top right is a 6A feed for what I think is called an auxillary contact? This when closed powers the pump interlock.

    Bottom center is the switched live straight to the pump

    Bottom right is the switched live to the pump interlock

    On the left hand side of this starter just out of shot are three other terminals that are connected to the timer, do all DOL starters have all these terminals?

    InkedIMG_0271_LI.jpg
     
  5. Wilko
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    Wilko Electrician's Arms

    Location:
    Berkshire
    Business Name:
    Wilko Electrics
    Depending on the pump they have, many have thermal overload built in by manufacturer and so just need switching.
     
    Last edited: Nov 21, 2017
  6. jaydub
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    jaydub Regular EF Member

    Location:
    Suffolk
  7. Lucien Nunes
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    Lucien Nunes Mercury Arc Rectifier Trusted Advisor

    Location:
    London
    The heater interlock circuit does not appear to be run through an auxiliary contact but through one of the three main poles. If the new starter has an overload with phase-failure sensitivity this won't work, as the current in all three poles needs to be equal. When used for single-phase this requirement is met by running the line through two poles in series as has been done here, and the neutral through the other. This would mandate an aux contact for the heater interlock, if it is on a separate circuit.

    You can't use the timer output for the heater interlock as the pump may be off while the timer is on, in manual mode or if the o/l has tripped. If they share a control circuit you might possibly use the pump contactor coil feed as the control supply for the heater switching, if its timer has volt-free contacts (so that the pump contactor doesn't stop the timer). But even this doesn't reflect the actual position of the pump contactor, so the aux contact is the way to go. The advantage of using an overload relay in the starter, over relying on the one in the motor if there is one, is that it will turn the heater off via the interlock if the overload operates. The one in the pump motor would stop that overheating but would leave the heater on.

    You can normally get to the necessary terminals for the control circuit on ordinary starters. The leftmost rocker switch on the panel (hand/auto) breaks the holding contact circuit in the auto position and connects the coil to the timer instead.
     
    • Informative Informative x 1
    Last edited: Nov 24, 2017
  8. Wilko
    Offline

    Wilko Electrician's Arms

    Location:
    Berkshire
    Business Name:
    Wilko Electrics
  9. Wilko
    Offline

    Wilko Electrician's Arms

    Location:
    Berkshire
    Business Name:
    Wilko Electrics
    Can I ask, what type of heater is it?
     
  10. Lucien Nunes
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    Lucien Nunes Mercury Arc Rectifier Trusted Advisor

    Location:
    London
    Hey I got a dumb! Actually ipf, tell me why my post is dumb and I'll provide an undumbification or at least make less dumber posts next time.
     
    • Like Like x 2
    • Winner Winner x 1
    • Dumb Dumb x 1
  11. ipf
    Online

    ipf Trusted Advisor

    Sorry pal.....accident....didn't even know I'd dumbed you.

    Well....at least it made you spit your dummy out...;)

    edit: This is weird, I've only just read your post??
    Has to be a first for everything though...can't remember ever giving one before.
     
    • Like Like x 2
    Last edited: Nov 24, 2017
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