Timer relay

Discussion in 'Electrical Systems' started by Coadster32, Sep 18, 2020.

  1. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

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    So last night, I got to mount up my duel electric fans, and bench tested the wiring for it. I didn't want to have both fans turn on at the same time drawing maximum current. I purchased a variable "timer on" relay, and hooked it up to turn my 2nd fan on 10 seconds after the first. Not certain if this topic was covered before, but figure I'd post this up to help anyone out in the future who might be interested. This is a relay only, so if you thought about trying it, no need to re-wire anything...just plug in this relay, and set the delay to your needs.
    fans2.jpg
    Here is a You-tube link of the bench test.



    Here is where I got the relay from

    receipt1.jpg

    This is the item number. It is adjustable from 1 second to 1 minute.
    receipt2.jpg
     
    dave@ztech likes this.
  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Delay relays have been around for years but they were either very expensive industrial units or some cheap looking electronic board configuration.
    I believe these are rated for 30 Amps. (Probably big enough for ONE fan.)

    These relays are fairly new to the electronics market.
    It's really a slick unit which is packaged nicely and plugs into a standard relay connector.

    The BU510TD is a "Delay On" timer... 1-60 second delay.
    The BU509TD is a "Delay Off" timer... 1-60 second delay.

    I bought one recently to experiment with a torque converter lock-up circuit but I ordered the wrong one. :(
    I needed the BU509TD to hold the circuit open (Delay Off).
     
  3. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

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    Agreed...one fan. I did this so I could run one circuit breaker to power both fans without tripping it...hence delaying the starting amps.

    Good idea on using it on the torque converter.
     
  4. ssupercoolss

    ssupercoolss Veteran Member

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    That looks like a solid relay. i like it. thanks for posting.


    I dont understand the delay off part.....how do you have yours wired?
    i have a cheap chinese delay timer set for 8 seconds....it works well on my Camaro, but doesnt work at all on the Monte Carlo. mines wired for power through the brake switch, to a normally open Vac switch, to the delay, then to the trans.
     
  5. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Mine is wired with the vacuum switch before the brake activated relay.
    The vacuum switch will work fine either before or after the brake relay.
    (It allows power through the switch as long as there is sufficient vacuum from the manifold to close the circuit.)

    Power -> vacuum switch -> brake relay -> 4th gear pressure switch (two contacts) -> lock-up solenoid.
    The solenoid is grounded to the transmission case.

    I tried use the "Delay On" timer/relay in place of the brake relay.
    (Using the Normally Closed side of the relay for power to the lock-up circuit.)

    That delayed the relay switching to the Normally Open side of the relay, which isn't used.
    So.. When I hit the brake, the power stayed live to the lock-up until the delay setting was reached. That's not what I wanted it to do. :(

    The brake and vacuum switches should be separate from the delay timer. (Like yours is wired with the Chinese circuit panel.)

    To really do it right... You would want the lock-up solenoid to engage a few seconds AFTER the transmission shifted to 4th gear.

    That would require running more wires inside the transmission and have the timer/relay outside and delay power to the solenoid.

    I haven't figured out a way to do that without opening my transmission and adding more wires.
     
    Last edited: Sep 20, 2020
  6. ssupercoolss

    ssupercoolss Veteran Member

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    This is exactly how mine works.
     
  7. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    How does your delay get a signal from the 4th gear pressure switch if it's in-line BEFORE the pressure switch?
    How many wires are you running to the transmission?
     
  8. ssupercoolss

    ssupercoolss Veteran Member

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    well, full disclosure, i also have a toggle switch, so it doesnt lock up just tooling around town. Most times i get on the highway, flip it on, and leave the switch on for 80 miles or so, but when i got the car, it was wired so as soon as it went into 4th, it locked up, which i found unbelievably annoying. The vac switch fixed that. if i flip the switch before im in 4th, it will shift into 4th, than once the vac settles out, sends the signal to lock up. i just have 1 wire to the trans.
     

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