Relay connection help

Discussion in 'The Projects Forum' started by armenon13, Jul 31, 2013.

  1. armenon13

    Thread Starter New Member

    Jul 30, 2013
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    Purpose: To run an automotive fan in the forward & reverse direction. The test cycle is "Forward direction ON - 1.5min, OFF - 1.5sec, Reverse direction ON - 1.5min, OFF - 1.5sec. It is a continuous process till you see some failure.

    Test Equipments: 2 DC power supplies, 1 DPDT solenoid (for forward & reverse mode), 1 Omron Timer relay H3CR-F8-300, 1 Relay SPST-NO-DM 4 pins 12VDC (Dayton 5z550), 1 10A fuse, 1 50A shunt.

    Test Set Up: I am using a DPDT solenoid to reverse the polarity. I am using an Omron relay timer to control the cycle time. I am able to reverse the polarity but the time period of switching the polarity is less than 10th of a second.

    How can I increase the time delay to 1.5sec before the DPDT solenoid reverses its polarity?

    Any help much appreciated.

    Cheers!!

    P.S.: I know the drawing is very rudimentary and I am trying to make a proper schematic.
     
    Last edited: Jul 31, 2013
  2. wayneh

    Expert

    Sep 9, 2010
    12,107
    3,038
    This is on the lab bench right? Automotive topics are taboo.

    Delayed turn on can be accomplished in several ways. A 555 timer IC is maybe the best because you can easily vary the delay time. The lowest tech solution would be to just put a resistor in series with the relay (as much resistance as you can without losing switching) and a big capacitor in parallel with it. The RC tank will prevent any quick movement of the relay.

    An intermediate approach is to use an RC tank for the timing on the base of a transistor which will turn on the relay. This is probably the approach I would use if the exact timing isn't too important.

    How much current does that relay require?
     
  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,980
    744

    Turn the timer dial to set your desired time datasheet
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,107
    3,038
    I was thinking that as well but a quick read didn't reveal a way to do it. I must've missed it.
     
  5. armenon13

    Thread Starter New Member

    Jul 30, 2013
    4
    0
    I'll look into the 555 timer IC info.
     
  6. armenon13

    Thread Starter New Member

    Jul 30, 2013
    4
    0
    I set the timer as per my requirement. The fan runs for 1.5min each in both directions but when it switches the polarity after the 1.5min ON cycle it does not stay OFF for 1.5sec. The DPDT solenoid relay immediately switches it & the time period is less than 10th of a second.

    The ON cycle is not an issue here, but I am trying to figure out how I can control the OFF period.

    I'll see if I can upload the actual test set up picture.
     
  7. armenon13

    Thread Starter New Member

    Jul 30, 2013
    4
    0
    I was wondering if I could use a flip flop relay to control the timing on the other relay.
     
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