1. #1
    While designing my control cabinet I want lights to indicate that the various voltage supplies are present to aid safety and trouble shooting.
    The voltages are 230v AC, 70v DC & 24v DC. I understand I can use a neon indicator for the 230v AC and an LED for the 24v DC, but what about the 70v DC, do I consider a filament lamp?
    The on-line calculators state that the use of a load resistor on an LED will dissipate excessive heat.
    Iím not up to speed on this subject so I would appreciate any assistance.
    It would also be good if the indicators could have a similar appearance.

  2. #2
    Jim I wouldn't bother with the 70Vdc has the 240Vdc transformer will power the 70Vdc and if you have bleed resistors on caps then they will be drained anyway, also the Drive LeD's will show any power left in the caps.!

    These are what I use on machine. . . Left to right.
    Control power ON/OFF 240Vac switch and Led light.
    Momentary Start/Reset button with 24Vdc Led
    Limit over ride switch with 24Vdc Buzzer.

    Also on the Main box there's a master power contactor switch which controls main power to everything, VFD, vaccum etc.

    Click image for larger version. 

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  4. #3
    Thanks Dean, another question.
    What is the best practice/method of taking multiple feeds off various supplies 240v, 70v & 24v, neutrals and earths in a control cabinet?
    I am trying to put a bill of materials together.

  5. #4
    Buy Din rail connectors (like these ! Din Rail Terminals 2.5mm CTS2.5UN, RS Electrical Supplies West Midlands) then connect several together with terminal strips to form distribution blocks. You can also get, Earth blocks, Fuse holders etc.

    Mains MCB's can fasten to the same Din rail.

    I don't use the linked company it's just a good example to show what I mean.

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  7. #5
    How about something along these lines ?

    Digital LED DC 30-70V Two-Wire Blue Voltmeter Panel Volt Meter Voltage Meter NEW | eBay

    As Dean says use proper din rail terminals, weidmuller is an industry standard but you can get cheaper clones, at least you can see the range on offer at their website.

    Last edited by EddyCurrent; 03-09-2013 at 07:28 PM.

  8. #6
    Jim Thought I better just make something clear.
    When I say connect together with terminal strips to form blocks. I mean You can buy strip with holes in that match connectors which fasten across top of the connectors all nice and neat.!!. . . I wasn't meaning you jump wires or anything like that. . Lol

  9. #7
    Thanks for the advice. I will look for suitable items and continue with the BoM.

  10. #8

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