Motor Reversing Intermittent Duty DPDT Solenoid Relay

[armenon]

I have an automotive fan that I need to run in the forward & reverse direction. For that I have the 12V Motor Reversing Intermittent Duty DPDT Solenoid. I have the DPDT solenoid coil terminals connected to the NC & NO on an Omron timer relay H3CR-F8-300. I am able to achieve the rotation of fans in both directions.

Issue: The OFF time period for the fan

Duty cycle for the fan.
Forward ON-1.5min, OFF-1.5sec
Reverse ON-1.5min, OFF-1.5sec

I have set the timer relay as per the duty cycle. The fan runs correctly in both directions during the ON cycle for 1.5min, but it does not follow the OFF cycle of 1.5sec.

The DPDT solenoid switches its polarity in less than 1/10th of a sec.

How can I have the OFF cycle adjusted?

Any help is appreciated.

Thanks.
ARM

 

[MikeMl]

I'm confused (and maybe you are as well). Are you not describing a three-state state-machine? How do you expect to put the motor into one of three states (stopped, CW, stopped, CCW) with a device that has only two positions (states)?

Hint, you need to use TWO relays...

 

[dr pepper]

Oh my head hurts.

You might have got away with just reversing the motor as its running, but if your doing it on a continuous cycle you'll rpobably ruin the motor after a while.

We need a drawing of your setup to see what your trying to do, there will be a way.

 

[alec_t]

How long does the fan take to come to a stop from full speed? Surely > 1.5s ?

 

[armenon]

Mike,
The DPDT solenoid relay does the purpose of forwarding & reversing the motor. I thought the timer relay would help me in the stop cycle, but it is not.
The next step I did was make a latching relay using 2 DPDT miniature relays. I thought that might help in the stop cycle, but it didn't. Most probably I am having the connections wrong I guess. I have a decent understanding of relays and what the terminals do but when it comes to connecting it to the other things in the set up I get confused. I'll try to attach a drawing & a picture if possible.
Thanks.

 

[armenon]

Dr.Pepper,
The test I am doing is a part of validation test. Yes, the motor will be ruined on a continuous cycle. I want to check the no.of cycles the fan would run before failure. The fan goes on an ATV where the fans runs in both directions depending on the vehicle & its surrounding condition. The stop cycle is 1.5sec which is less as the fan takes about 7-9 sec to stop, but that's the duty cycle.
I'll attach a drawing of the set up & also a picture if possible.
Thanks.

 

[armenon]

Alec,
The fan takes about 7-9 sec to stop completely. But since the test I am trying to do is a part of validation test, I am trying to see the no.of cycles the fan will run before any failure.
Thanks.

 

[MikeMl]

Mike,
The DPDT solenoid relay does the purpose of forwarding & reversing the motor. I thought the timer relay would help me in the stop cycle, but it is not.
The next step I did was make a latching relay using 2 DPDT miniature relays. I thought that might help in the stop cycle, but it didn't. Most probably I am having the connections wrong I guess. I have a decent understanding of relays and what the terminals do but when it comes to connecting it to the other things in the set up I get confused. I'll try to attach a drawing & a picture if possible.
Thanks.

You need to treat the timer relay as a free-running oscillator, with a duty cycle of 90s On and 1.5s Off.
Use the timer relay contact to apply power to the motor ( so it only runs for 90s).

Behind the timer, you need a "toggle" (a.k.a. Flip-Flop). It can be a solid-state IC chip or a network of relays (search for toggle relay on this site, there have been several threads).

The toggle relay output is used to reverse the direction of the motor. Note that this conforms with my earlier statement about needing multiple relays

 

[armenon]

It's a very basic drawing. I hope it helps.

 

[MikeMl]

Your solution lacks the "divide-by-two" functionallity that the toggle (flip-flop) would provide. The toggle makes it so that the motor can run forward/reverse on every other cycle of the timer.

 

[armenon]

Mike,
I'll prefer the relays & I will look into what you told. The duty cycle has to be continuous process, so I can't use a DPDT toggle switch.

Mike/Dr.Pepper,
I am attaching a few pics of the test set up. Hopefully that will help a little more.

The first 2 pics shows the test set up. The 3rd pic is the 2 miniature DPDT relays that I had thought of for making a latching relay.

Thanks.

 

[armenon]

Schematic of the DPDT reversing solenoid

 

[alec_t]

The fan takes about 7-9 sec to stop completely. But since the test I am trying to do is a part of validation test, I am trying to see the no.of cycles the fan will run before any failure.

But is your validation test itself valid? . You would be forcing the fan to reverse before it has come to a halt naturally. That could stress the fan and lead to premature failure. Or is this forced reversal / premature failure what you want to test?

 

[armenon]

Alec,
Yes, it is valid. Actual vehicle conditions are different and we are trying to simulate the actual conditions that can occur. Failure is what we intend to see in this test. We just want to know how many cycles the fan can run without any performance deterioration.
Thanks.

 

[MikeMl]

View attachment 75369

Schematic of the DPDT reversing solenoid

Ok, I see that what I have been saying is correct. The reversing relay you linked has two momentary pulsed coils. To reverse, you must pulse the two coils alternatively. You would have to build a "toggle" to go between the timer output and the two coils. It is up to the toggle to produce the two alternating momentary pulses for the two coils.

In the toggle made from relays that I linked to, there is no reason that you have to use a momentary push-button. That contact could come from the timer, instead...

I just downloaded the timer data sheet. It does NOT have two alternating outputs.

 

[armenon]

Mike,
So do I need to use another timer as well or do I need to use a latching relay (3rd pic shows 2 miniature DPDT relays that I thought I'd use to make a latching relay). I find reading the schematics a little confusing.
When you say "toggle" does that mean flip-flop relay? What would be the timer output? Do we need that toggle between the DPDT solenoid & the timer relay?
(Some of my questions might sound stupid, please bear).
Thanks.

 

[MikeMl]

Mike,
So do I need to use another timer as well

That is one way to do it. Wire the first so that it triggers the other and the other triggers the first. I would have to look at the Omron data sheet in some detail to figure out how to do this...

The other way is to use one Omron timer which drives a toggle-relay which in turn drives the reversing solenoid.

or do I need to use a latching relay (3rd pic shows 2 miniature DPDT relays that I thought I'd use to make a latching relay). I find reading the schematics a little confusing.

Reconfigure the two latching relays into a toggle as per the web site I linked.

When you say "toggle" does that mean flip-flop relay?

Yes, however it takes two to three physical regular relays to make the toggle.

What would be the timer output? Do we need that toggle between the DPDT solenoid & the timer relay? ...

Answered above.

 

[armenon]

Mike,
I'll try what you told me in the next 2-3hrs and will let you know. I was going through the link that you gave, what do I do in place of the push button?
Thanks.

 

[armenon]

Ok, I see that what I have been saying is correct. The reversing relay you linked has two momentary pulsed coils. To reverse, you must pulse the two coils alternatively. You would have to build a "toggle" to go between the timer output and the two coils. It is up to the toggle to produce the two alternating momentary pulses for the two coils.

In the toggle made from relays that I linked to, there is no reason that you have to use a momentary push-button. That contact could come from the timer, instead...

I just downloaded the timer data sheet. It does NOT have two alternating outputs.

Mike,
What exactly do you mean by timer does not have two alternating outputs? How does it affect the set up that you have mentioned?
Thanks.

 

[MikeMl]

Mike,
What exactly do you mean by timer does not have two alternating outputs? How does it affect the set up that you have mentioned?
Thanks.

No. It is because the timer has only one output that you need to add the toggle behind it.