Dead Stair Lift help

Discussion in 'General Electronics Chat' started by frank55, Dec 9, 2013.

  1. frank55

    Thread Starter Member

    Dec 6, 2013
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  2. inwo

    Well-Known Member

    Nov 7, 2013
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    Not if it checks ok. Try it when disconnected to be sure.

    If it just hums, it's the starting switch. Is it a motor that you can spin to start?
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You mentions it is dead, so presumably there is nothing from it at all?
    Do you have any schematics? Is it in fact a 1ph induction motor ?
    Max.
     
  4. ian field

    Distinguished Member

    Oct 27, 2012
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    If its an induction motor that doesn't start spinning when powered, they tend to let the magic smoke out fairly quickly - if its buzzing loudly, switch it off PDQ!

    If the capacitor was on its way out; I'd expect a fair bit of heaving and grunting as it spins up to speed.

    If its dead, look for a break in the circuit somewhere - if it let the magic smoke out while no one was looking, the break could be inside the motor.
     
  5. frank55

    Thread Starter Member

    Dec 6, 2013
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    Thanks guys: I'm home on my PC checking if there is any schematic on it, but it seems this is an old commercial Concord Liberty made in Canada year 2000,
    it's complete dead no Hum from motor no action at all.
    it doesn't have switches on the chair arms, it has 2 switches that someone else has to activate when the disabled person is on the chair.
    The switches are similar to these on the outside see link, i did not opened them yet
    but i assume that they are like these.I will open these switches tomorrow and
    will take my capAnalyzer DCR ESR 88A to check DCR the Cap.
    the cap is soldered to the wires and is hard to get access to the inside where the motor is, i'll give it a try tomorrow and post results, thanks


    http://i111.photobucket.com/albums/n160/gmatov/P8150712.jpg
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Looks like dual DPDT switch with steering diodes.
    I imagine there is a control box somewhere with relays and possibly fuses in?
    Max.
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It appears that they were bought out by Savaria in 2005 and under support only give out service info to their dealers?
    If so, you may be in for a bit of reverse engineering?
    Max.
     
  8. frank55

    Thread Starter Member

    Dec 6, 2013
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    Thanks MazHeadRoom: Today i return to check the big Capacitor and it's good, also opened the 2 switches and found out it has another Switch in the chair arm that one i did not check yet, but the 2 switches shown in the pic
    are alike, and i checked the diodes and switches and they're good too,

    Friday i'll go there again and will take some tools so i can get the to motor and possible some circuit board,but i think this one is only AC electric Voltage and has few electronic components i think this one has some safty sensors that might cause the no working state,
    Thanks.


    http://i111.photobucket.com/albums/n...v/P8150712.jpg [​IMG]
     
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If it is an AC motor control, I would suspect it is simple switching via relays etc.
    Max.
     
  10. frank55

    Thread Starter Member

    Dec 6, 2013
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    Thanks MaHeadRoom: what do think might be bad in the stairlift, the motor or some sensor or even the relay? or maybe there is a simple fuse?,
     
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Could be anything, in the absence of any kind of documentation it is a case of reverse engineering and checking the obvious at first.
    Limit switches and fuses and tracing power step by step.
    Max.
     
  12. frank55

    Thread Starter Member

    Dec 6, 2013
    253
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    Hi MaxHeadRoom : today i went to check the inside of the Stair lift and i checked the fuse and it's good i also checked the motor and it seems to be ok and i saw a circuit board with many components caps diodes resistors and other components it's kinda hard to trouble shoot a circuit board without any schematic
    i checked the arm switch which has only 2 wires that connect to the circuit board! which is strange i think it should have at least 3 wires! i disconnected them from the board and connected DM in diode position and measured one side of the sw has continuity and the other has nothing.I'm not understanding this switch!
    what you guys think i should do next? thanks
     
  13. MaxHeadRoom

    Expert

    Jul 18, 2013
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    First I would establish exactly what has power, IOW is there a supply or board etc that looks like the power supply is missing to etc.
    Any LED's lit?
    What is the motor technology? AC induction, DC?
    Max.
     
  14. frank55

    Thread Starter Member

    Dec 6, 2013
    253
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    Thanks Max; today i went there and chaecked hand switch it's ok,
    checked other connections and also did not find anything wrong, i brought the main circuit board home to check some components,already checked caps resistors and diodes and all good,there are some other components that i realy need your help how to check if these are ok, i took some pictures of the circuit board,i know a bit of electronics but more knowledge of tvs, thanks in advance
     
  15. frank55

    Thread Starter Member

    Dec 6, 2013
    253
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    Here some more pic.
     
  16. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    As Max said, do some reverse engineering. Start with the power source, 110VAC I assume?
    Where does it go on the board. You will have to draw the circuit yourself, it is apparently just a double layer PCB, so not an impossible thing to do.

    There are tons of relays on the board, what is their voltage and where does their voltage come from?
    Where do the motor wires go to? Are they switched through the components (I suspect relays) P1 and P2. These are probably high contact current rating relays, so I would suspect motor is switched with them.

    Start with the power supply.

    These guys may have some parts or info too: http://www.concordlondon.com/s4000oldlibertycirc.html
     
    Last edited: Dec 19, 2013
  17. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It also appears to be a 1ph induction motor, if so, it is unlikely that there is any speed control, by motor rpm anyway.
    Max.
     
  18. frank55

    Thread Starter Member

    Dec 6, 2013
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    Thanks a lot i appreciate your help,but it seems to be a too big job and i don't think i'm up to it,
    if the machine was at my house sure i could try but it's not, and i don't have the time nor the patience to do it, I'll give the info to my nephew for
    the board and if he wants to take a chance on ordering it, but it's too old machine and i don't think it's worth it,thanks.
     
  19. gerty

    AAC Fanatic!

    Aug 30, 2007
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    And if you haven't already, check the seat sensor. Most have a switch in the seat to stop it if a person falls off the seat. Much like a riding lawnmower.
     
  20. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Come on, I just asked them to send me a wiring diagram. Put some hours into it and you are going to get it to work again. :)

    See the attached installation manual with wiring diagram.

    Let us know if you want to continue .
     
    inwo likes this.
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