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help needed with electrical connection please

Discussion in 'General Electronics Discussion' started by Ian Fitzwater, Dec 20, 2016.

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  1. Ian Fitzwater

    Ian Fitzwater

    Dec 20, 2016
    Hi, can someone please help me with an electrical connection to a spa ( hot tub) control unit. I have recently purchased a unit from Trinity electronic labs in the US and have tried to connect it as per their instructions ( see pdf file attached) and not only did I ask the company beforehand if the way I was going to connect it was correct, I made sure I followed their onine guide- only to fry the unit straight away-
    I find the instructions a little ambiguous, as it speaks about the 120v-240v transformer switch having to be in a certain position if a neutral wire is present or not-
    I have had the unit repaired locally by a technician, he replaced the transformer which had died- and he tells me he can´t understand how the unit can possibly work because there is no connection between L1 and the transformer ( which is how the company tells you to connect)
    I have tried contacting Trinity Electronic labs several times now, on the phone I encountered someone who told me he is the owner and he spent an hour yelling at me saying his instructions were quite clear, I have since emailed him twice to get some definitive idea how to connect the unit and he will not reply- hence my presence here as I am at the end of my tether so to speak- the tech guy is reluctant to hook it up again as he thinks it will blow the transformer again... can anyone give me any suggestions please?

    Attached Files:

  2. duke37


    Jan 9, 2011
    In the colonies, they have an electricity supply of 120V-0-120V. Small appliancies connect to 0 (N) and one of the L connections. Larger appliances are connected between L1 and L2 to get 240V. Neither L1 or L2 are neutral, they have the same voltage but in antiphase. It looks as if the spa can run on either 120V or 240V depending on the connections.

    It looks as if you have a sensible cautious helper. If you try again and are only running the control system, then put a filament lamp in series as an indicator of current and as a protection for the transformer.

    The US power frequency is 60Hz which means that 50Hz in europe will be hard on the transformer but it should be able to stand this.

    I have been given US radios to repair which were intended for 120V but had been connected to 230V.
  3. Ian Fitzwater

    Ian Fitzwater

    Dec 20, 2016
    thanks for your reply, are you saying however I need to connect to L1 and L2 with my two wires? sorry if this is a stupid question but L1 and Neutral together do nothing- hence our confusion
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    Nov 17, 2011
    Duke said it all, maybe a bit of rephrasing helps:
    L1 - neutral would be 120 V in the USA. As the appliance requires 240 V, it needs to be connected between L1 and L2 (as per the appliance's nomenclature) which translates to L - N of the mains in European nomenclature. In both cases the apliance will operate from 240 V.
    So connect L1(appliance to L(mains, France) and L2(appliance) to neutral (mains, France).

    Á plus,
  5. Ian Fitzwater

    Ian Fitzwater

    Dec 20, 2016
    thanks so much for the clarification and your patience- one last question with regard to the transformer voltage switch where he states if there is no neutral wire, switch must be in 240v position, if no L2 switch must be in 120v position, if both are present it doesnt matter- once again, I can´t make head nor tail of what that means... sorry
  6. Ian Fitzwater

    Ian Fitzwater

    Dec 20, 2016
    I have just tried to connect as per above and that produces absolutely nothing- is there anyone on here that is able to test this board for faults if I send it to them? I am happy to pay, just at a dead end and need some expert help please
  7. BobK


    Jan 5, 2010
    The switch should be in the 240 position. If you connected in the 120 position, you probably blew out a lot of electronics by giving them twice the voltage they are expecting.

  8. Tha fios agaibh

    Tha fios agaibh

    Aug 11, 2014
    It may mean that the control transformer is stepping down 240 to 120.
    If 240 is applied across L1 and L2 both windings of the transformer are used.
    Whereas if 120v is applied to L1 and N, only half of the primary windings are used.
    That would explain why the switch position doesn't matter if both wires are hooked up. In other words, if the Neutral is hooked up it will have 120v to use even if 240v is applied across L1-L2.

    That said, I strongly caution you to get someone qualified to look at your install. The fact that your "technician" can't figure it out doesn't bode well.
    Here in the US circuits are designed to trip a circuit breaker if a fault (short) occurs between L1 and N or, L2 and N (or ground).

    If you apply European 240v and N to terminals L1 and L2 as Harold suggested, it will work but will not trip a circuit breaker if L2 shorts to ground or N because it is grounded. In other words L2 on this spa was not designed to be grounded (hooked to N) and could therefore present a hazard.

    I wouldn't take any chances with a hot tub.
  9. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir Ian Fitzwater . . . . . . .

    Looks like ever since the 7th of January of 2013, that very first , top left corner pictorial reference has always been wrong.
    But . . . all is correct, if using either the wire marking label at /on the power connector block proper or if referring to the adjunct silk screening being on the PCB proper.

    If this unit is being laid out . . . . bare bones . . . . . with no wiring being connected into it at all, it should be able to take an ohmmeter and read . . . say, in the order of ~200 ohms at the power input block terminals L1 and L2 with the units control transformer 240/120 slide switch being in its 240 volt position.
    Then slide the switch to its 120 volt position and then see if that ohmmage doesn' t decrease on down to ~ half that previous value.
    If so, both primary windings are OK as well as the switch contacts integrity.
    BUT you never want to have left that switch . . . . or temporarily switch into the . . . . 120 volt position, if your AC power supply is being 240VAC.

    The rest of the wiring installaton seems straight forward in the respect of confirming the voltage operations specs of the auxilliary pumps and motors,
    as per their being either 120 or 240 VAC rating / types, and then connecting their wires into their assigned proper 240/120 VAC voltage busses.

    The very bottom illustration is common 240 VAC installation with use of all four power wires and being installed with proper wiring service loop lengths.

    Looks like, by this Triads top of the page specification # 8 , that a fused secondary is expected, as well as per the sub 3 clause at the very bottom of the page.
    So a popped fuse may also be involved, if having incurred a primary 240 VAC being applied , with the 240/120 slide switch being in its 120 volt position.




    73's de Edd
    Last edited by a moderator: Dec 21, 2016
    Martaine2005 and Harald Kapp like this.
  10. Ian Fitzwater

    Ian Fitzwater

    Dec 20, 2016
    many thanks for all your help! it has helped me work out how to connect the unit safely and test it- so far have ascertained the transformer is functioning correctly and power is distributing throughout the mother board, currently unable to make the control panel function, so assuming it has been compromised, there is power to the connector block where it connects - but I am unable to verify that the transistors on the mother board have not been damaged either. Either way, I have lodged a complaint with the company as I feel that their instructions are not clear, and furthermore, I did ask for precise instructions for my application beforehand which were met with a very off hand reply- that was at best ambiguous- you may be thinking, ¨why didn´t he get an electrician to hook it up....?¨ however the site is quite adamant that this is a simple procedure, and I am normally quite capable of something as straight foward as this- so thanks again for you all your assistance and patience.
  11. Ian Fitzwater

    Ian Fitzwater

    Dec 20, 2016
    Hello and thank you to all the members who have helped me with my problem above with my spa control unit. I have succeeded in connecting it correctly as per 73s de Eddś instructions, having replaced the burned out transformer, and now have power coming out the other side and distributing to various connections for the pumps etc. However, I cannot find power going to the control pad and feel that there is some other component that has been compromised. I am unable to test any further as I am not clever enough, and have tried to get a local electronics shop to do this but they don´t seem very motivated- therefore I am wondering if someone on this forum would be willing to let me send the mother board to them from here in France, for testing to see what is and what is not functioning. Of course I will pay for these services. Any help or advice will be very welcome please.
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