The ratchet or impulse relay are not common.

They work just like a retractable ballpoint pen.

Put a micro switch on the point and you've got one.

Each time power is applied, it ratchets to the next position. on-off-on-off etc.

This is connected to your reversing relay.
First power cycle will power motor thru 2nd relay that is "on".
Next power cycle motor will be powered thru 2nd relay "off".

Now if you found one with enough contacts. Would not need the second relay.

I'll search for one.

 

Not inexpensive, but here you go!

http://www.ebay.com/itm/NEW-GE-CR12...710?pt=LH_DefaultDomain_0&hash=item1c269572a6

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Each power cycle reverses motor.

I drew a picture but my cam battery is dead.

 

You are great - TY again for hanging in!

I did some research early this morning and read about Latching relays, then Ratchet (Ratchet is a type of Latching, yes?).
Hence, power would not have to be continuous and your explanation of ratchet would be the portion which allows reversal of polarity. Am I getting it?

Rainer

 

Yup, that is a little expensive. Ouchhhh.

I don't mind spending as much as it would cost to buy a door opener for the satisfaction of learning something new, but when it exceeds - Hmm

Not inexpensive, but here you go!

http://www.ebay.com/itm/NEW-GE-CR12...710?pt=LH_DefaultDomain_0&hash=item1c269572a6

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Each power cycle reverses motor.

I drew a picture but my cam battery is dead.

 

First decide what way will work. Then look to save money.

If you want to try the idea, I'll keep looking for surplus relay.

Do you have a way to monitor the door so you know if it's open or closed?

This one doesn't have enough contacts, but you can use it to activate your other relay.

http://www.ebay.com/itm/Vintage-Com...516?pt=LH_DefaultDomain_0&hash=item3a95c60bdc

 

Like this..............................................

Ebay http://www.ebay.com/itm/POTTER-BRUM...873?pt=LH_DefaultDomain_0&hash=item2c890a7c99

 

If you just need memory, can you use a magnetic latching type? P&B have them among others?
Max.

 

lost my last response, hope I am not duplicating.

If I use a 12 volt always on supply, could I then use the current DPDT relay (which I already have) and two on/off switches? Would that work?

 

Yes, if you turn ip outlet on for duration of one period.

For example:
N.C. contacts of relay run door closed until stopped by switch.
Ip outlet turns on relay, which runs door open until outlet turns off.

edit:
need 120vac relay

 

Would IP outlet be able to activate relay and let door go down until switch off is encountered, IP outlet will be shut off via IP, then next time IP switch is powered on again and activates Relay, lets motor go in reverse (door up) until another switch turns it off, IP power off?

Rainer

 

Would IP outlet be able to activate relay and let door go down until switch off is encountered, IP outlet will be shut off via IP, then next time IP switch is powered on again and activates Relay, lets motor go in reverse (door up) until another switch turns it off, IP power off?

Rainer

Yes, with an impulse/ratchet/latching relay.

We seem to be going in circles.

 

Or maybe not.

Woke up with this idea.

Only two relays and two N.O. limits.

I'll look for errors tomorrow.
Only thing comes to mind now, it needs reset if it fails mid stroke.

Which ever switch is "on" will latch direction relay on "power up".

When motor runs to opposite limit, the second relay will latch also. Stopping motor.

"Power down" = unlatch both relays.

Repeat.

I would welcome another opinion. I haven't built it. Seems too simple.

Easiest way to follow circuit is to picture the two limits as momentary switches.
They will only be "on" until motor moves off the end points.

I believe this to be a unique method!

 

What about if the switches are two position maintained, and the two limits added either side of the motor with reverse diodes across them?
Max.

 

Tried similar, but then needed another set of switches, to set "direction" on "power up".

Op is set on a single set of switches, no continuous power supply, max of two regular relays, no latching relays.

I didn't believe it could be done.

 

If this works for you, I'll draw a picture or add terminal numbers.

 

I certainly don't think I fully understand the schematic, but if you believe it would work I would love the relay numbers!
And again, a 12V continuous PS would not be a problem! (which it looks like there is on the drawing)
Again, TYVM!

Rainer

 

I was hoping for validation before asking you to try it.

I'm not up for building it today.

No need for continuous power on this one.

It uses the latched relays to shut down after first cycle.
Then uses the limit switch to set direction on next power cycle.

I'll need a link to relay voltage and pin-out.

Do you have 12vdc power supply?

 

Yes, I do certainly have a 12V power supply.
That schematic actually makes sense to me - I did not know that the switching/ on-off of current occurs on the same side of pins - learn something new every day from you,
TY

Rainer

 

If the above relay pin-out is correct..........................

At start of cycle:
One of the switches will be closed. ie. door will be open or closed.

When 12vdc power is turned on by outlet, that switch will energize one of the relay coils. That coil will remain on, being held on by one if it's own contacts.

Same relay powers motor until the other switch "switches on" and energizes the other relay.

Both relays energized = motor off.

Motor will remain off until the next power off-on cycle.

 

TYVM for all your thinking and drawing!!

I will try this,

Rainer