Results 1 to 3 of 3

Thread: Relays and LED lights

  1. #1
    Platinum Member
    Join Date
    Mar 2022
    Location
    South Africa
    Posts
    2,274
    Thanks
    60
    Thanked 103 Times in 98 Posts

    Relays and LED lights

    Friday brain teaser:

    Back in the days of energy savers and incandecent lamps, we knew the load had to be calcualted depending on the type of lamp, it would be calcualted as inductive or resistive loads.

    Now we have LED fittings, they dont flicker to switch on indicating they are and inductive load, yet they are controlled by a electronics, they switch on instanntiously like a resitve load.

    The question would be, how do you select relays for switching, do you use the industive rating of a relay or the resistive rating of the relay.

  2. #2
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    3,507
    Thanks
    138
    Thanked 697 Times in 595 Posts
    Blog Entries
    1
    I am going to throw a spanner into the works here.
    LEDs are more capacitive than resistive and inductive, unless they have a built in PFC which then makes them resistive.

    a nice article here Are LED Lights Inductive Or Resistive Load?
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

  3. #3
    Platinum Member
    Join Date
    Mar 2022
    Location
    South Africa
    Posts
    2,274
    Thanks
    60
    Thanked 103 Times in 98 Posts
    I went to site last weekend to fit a couple of dimmers and a replace a tons of old 50 Watt downlighters.

    I ordered a the dimmers and requested a 500 watt LED specific dimmer ( not something I have done in a while) the sles guy asked why 500 watt, a 275 watt should do it. After a few quick calculations It runs out a 275 watt was way more than I needed.

    I am busy installing a bunch (more than 30) of floodlight, so I thought best a I get a 25 amp relay to control the lights, turns out all the lights draw just under 1.3 amp. Really only 1.3 watts, so I used a 5 amp relay. Hence the question.

    So how do you rate realys and contactors for LEDS?

Similar Threads

  1. [Question] 12 VDC Relays inside light switches
    By ians in forum Electrical Contracting Industry Forum
    Replies: 1
    Last Post: 03-Nov-20, 05:50 AM
  2. Ripple Control Relays
    By rohor in forum Electrical Load Shedding Forum
    Replies: 10
    Last Post: 22-Jun-20, 01:23 PM
  3. intrinsic relays
    By bergie in forum Electrical Contracting Industry Forum
    Replies: 2
    Last Post: 26-Mar-11, 08:52 AM
  4. lem lights
    By murdock in forum Energy and Resource Conservation Forum
    Replies: 7
    Last Post: 09-Dec-10, 09:04 AM
  5. And the lights go out again.
    By Dave A in forum Electrical Load Shedding Forum
    Replies: 71
    Last Post: 25-Feb-08, 04:38 PM

Did you like this article? Share it with your favourite social network.

Did you like this article? Share it with your favourite social network.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •