Linear Actuator Switch - Help?

[Guest Peter the Greek]

G'day all,

 

This is a bit of an odd one for this forum, but I thought I'd try my luck given the depth of knowledge here.

 

I've got a 12v actuator, I need a switch like a 24 hour light timer that will extend the actuator for X hours a day and retract it for Y hours. A simple on/off wont work as it needs to change the polarity to close it (or open it)

 

Any thoughts/ideas for an off the shelf all in one product? Or maybe how I could do this?

 

Any help would be most appreciated.

 

Many thanks,

Peter

 

[stereo coffee]

Hi Peter

The usual answer with timing periods is to use a 555 timer integrated circuit, the kit at Jaycar called the Flexitimer can do this using a 555, but they also have a built unit, that might suit your purpose, as it has a continuous run on period off period, that can be set for the number of hours mins and seconds you need     https://www.jaycar.com.au/12v-programmable-interval-timer-module/p/AA0378

 

Understanding relay connections, here is some general information   https://en.wikipedia.org/wiki/Relay

The three terms are Normally Open shortened to NO ,  Normally Closed NC ,   and Com usually the signal or voltage you are distributing to NO or NC contacts. 

[bob_m_54]

There are many ways you could do it, but a simple way would be

Use a 12V timer to operate a changeover relay:

12V programmable Timer

Changeover Relay

[Guest Peter the Greek]

@bob_m_54

@stereo coffee

 

Thanks guys. I feel completely retarded about this. My mind just doesn't seem to grasp the diagrams.

 

I've got a 12v timer switch. It's got a + and - input and output

 

They sold this relay.

 

How do I wire this?

 

So I've got +/- from the battery.

 

That plugs +/- into the timer

 

The timer plugs into the relay at 7 and 8?

 

I plug the actuator into 3? and 4?

 

[stereo coffee]

7 hours ago, Peter the Greek said:

@bob_m_54

@stereo coffee

 

Thanks guys. I feel completely retarded about this. My mind just doesn't seem to grasp the diagrams.

 

I've got a 12v timer switch. It's got a + and - input and output

 

They sold this relay.

 

How do I wire this?

 

So I've got +/- from the battery.

 

That plugs +/- into the timer

 

The timer plugs into the relay at 7 and 8?

 

I plug the actuator into 3? and 4?

 

Your description is correct, but missing essential detail about the timers specifications, and detail you describe as the actuator, presently referred to as ( like a light timer), if it is a light you are switching,  what are its voltage and current requirements. The relay you show, may or may not be suitable for switching the needed voltage and current.     

 

Also detail about the timer; specifications is required, for instance with any relay coil when it actuates, it creates a back EMF ( back electromagnetic force ) The absolute minimum requirement, is to fit a power ( IN4002 ) diode with its anode to the negative of the coil and its cathode (with the band )to the positive. of the coil. The timer may have this already installed - you would hope !.  Also most relay activation usually involves a transistor to do the load of the switching, and the timer specification, may or may not have the transistor installed. Detail therefore needed about the timer. Without the diode, the coil when it activates can damage circuitry above it.   The timer may also include detail about if it requires a certain current, vs direct connection to the battery, information which is presently missing, and may include detail about its current draw , reflecting on the size of battery.  

 

Also more detail about the actuator will help. Relays have specification to switch current, and presently I see no detail about the load you are switching.     Generally the common pole  on 3, or 4, if used,   will enable you to switch two devices on and off at required intervals  You would usually only need to use one of the poles of the relay either 3 or 4 and wire the load you are switching, using only one of its polarities.  Your diagram shows  the contact at 2, and 1 is normally OFF, meaning you would wire contact 2, or 1 as the case may be ,  to activate when the coil ( via the timer ) engages.   

[bob_m_54]

Providing the relay contacts are rated to the current draw of the actuator, then:

 

Timer output terminals to 7 & 8, making sure you have polarity correct. (as you said)

Battery POS to 5, and NEG to 6.

Actuator POS to RLY terminals 1 & 4 (1&4 being linked by a jumper)

Actuator NEG to RLY terminals 2 & 3 (also linked by a jumper)

 

If the actuator works in reverse to what is required, you can either change the polarity to the relay common terminals (5 & 6) or the polarity of the actuator terminals.

 

Edit: Like in this diagram, with the timer contacts as the switch. (note your terminal numbers are different though)

Edited May 2, 2020 by bob_m_54
picture

[stereo coffee]

Why the snubber diode, and current limiting for the coil  which I described , but missing in your diagram is needed:    https://resources.altium.com/p/why-you-should-use-a-flyback-diode-in-a-relay-to-prevent-electrical-noise-in-your-circuits. 

22 minutes ago, bob_m_54 said:

Providing the relay contacts are rated to the current draw of the actuator, then:

 

Timer output terminals to 7 & 8, making sure you have polarity correct. (as you said)

Battery POS to 5, and NEG to 6.

Actuator POS to RLY terminals 1 & 4 (1&4 being linked by a jumper)

Actuator NEG to RLY terminals 2 & 3 (also linked by a jumper)

 

If the actuator works in reverse to what is required, you can either change the polarity to the relay common terminals (5 & 6) or the polarity of the actuator terminals.

 

Edit: Like in this diagram, with the timer contacts as the switch. (note your terminal numbers are different though)

 

Edited May 2, 2020 by stereo coffee

[bob_m_54]

Yes, I agree, the snubber is needed, but I was illustrating which way the terminals should be connected.

 

Actually it looks like the diagram is of an Omron LY2N DC, from this link:

https://www.farnell.com/datasheets/2158297.pdf

 

But he should use the LY2N-D2, which has the snubber. (or add the snubber as you suggested)

Also, the relay is rated to 10A switching capacity

Switching contact rating for inductive load depends on the  UL, CSA specs

Edited May 2, 2020 by bob_m_54

[bob_m_54]

@Peter the Greek What is the Make and Model Number of the timer switch, and the Actuator you have?

[Guest Peter the Greek]

27 minutes ago, bob_m_54 said:

@Peter the Greek What is the Make and Model Number of the timer switch, and the Actuator you have?

Thank you so much for your help with this.

 

The actuator is 12v and draws 6amps at full capacity - I asked the manufacturer about that

 

 

Here is the switch

 

 

 

 

Edited May 2, 2020 by Peter the Greek

[bob_m_54]

Edited May 3, 2020 by bob_m_54

[Warren Jones]

The LED is incorrect polarity in the above pic.

 

The other thing is does the actuator have internal limit switches? if it does you can wire like above. An automotive relay will work and these can be rated for high current, just make sure it's not a latching relay.

 

If the actuator DOES NOT have limit switches then the above will burn the motor out. Just checked the spec it does have adjustable limit switches.

Edited May 3, 2020 by Warren Jones
addition info

[bob_m_54]

4 hours ago, Warren Jones said:

The LED is incorrect polarity in the above pic.

 

The other thing is does the actuator have internal limit switches? if it does you can wire like above. An automotive relay will work and these can be rated for high current, just make sure it's not a latching relay.

 

If the actuator DOES NOT have limit switches then the above will burn the motor out. Just checked the spec it does have adjustable limit switches.

Good pickup on the LED, actually there is a mistake in the diagram. POS and NEG on the timer should be reversed, and hence the protection diode.

 

Now edited to reflect correct polarity. @Peter the Greek

Edited May 3, 2020 by bob_m_54

[Guest Peter the Greek]

1 hour ago, bob_m_54 said:

Good pickup on the LED, actually there is a mistake in the diagram. POS and NEG on the timer should be reversed, and hence the protection diode.

 

Now edited to reflect correct polarity. @Peter the Greek

 

Awesome, thank you so much for your help! I got side tracked today (life on a farm), but hopefully I'll get the work done over the next week. Greatly appreciate your input.

 

5 hours ago, Warren Jones said:

The other thing is does the actuator have internal limit switches? if it does you can wire like above. An automotive relay will work and these can be rated for high current, just make sure it's not a latching relay.

 

If the actuator DOES NOT have limit switches then the above will burn the motor out. Just checked the spec it does have adjustable limit switches.

Yep, it does. Came pre-set which is good - the last time we went through this the relay etc was all in a box, but the actuator settings wasn't (different brand)....total friggin nightmare

 

 

[soundbyte]

2 hours ago, bob_m_54 said:

hence the protection diode

The protection diode is shown as being internal to the relay so should not be  needed on the controller.

[bob_m_54]

16 hours ago, soundbyte said:

The protection diode is shown as being internal to the relay so should not be  needed on the controller.

The internal diode is actually a LED, to indicate when the relay is activated.

[soundbyte]

18 minutes ago, bob_m_54 said:

The internal diode is actually a LED, to indicate when the relay is activated.

Not according to this schematic you posted?  See below, diode connected between pins 7 and 8?

It only indicates that voltage is across the relay coil, it will not indicate that the contacts are actuated if there is a fault in the relay or wiring.

I would be putting any activation indication across the actuator connections, it would mean two LEDs back to back (one orange (actuator out), one green (actuator in) ?), a bridge rectifier could be used with the LED and resistor across that, but that is overkill.

On 02/05/2020 at 12:07 PM, bob_m_54 said:

 

 

[bob_m_54]

10 minutes ago, soundbyte said:

Not according to this schematic you posted?  See below, diode connected between pins 7 and 8?

It only indicates that voltage is across the relay coil, it will not indicate that the contacts are actuated if there is a fault in the relay or wiring.

I would be putting any activation indication across the actuator connections, it would mean two LEDs back to back (one orange (actuator out), one green (actuator in) ?), a bridge rectifier could be used with the LED and resistor across that, but that is overkill.

 

That's the relay I said would have been better to use, but I was under the impression that @Peter the Greek already had the relay as per his first post, without the protection Diode. In his latter post, where he posted a pic of the timer, it shows a protection diode is supplied with the timer (as drawn in my schematic), so it doesn't really matter. His relay (LY2(Z)N DC model) only has the indicator LED.

 

Yes, he could use extra LEDs to indicate whether there is current, while the actuator is being driven, but it isn't really required.

Edited May 4, 2020 by bob_m_54

[Guest Peter the Greek]

13 minutes ago, bob_m_54 said:

 a pic of the timer, it shows a protection diode is supplied with the timer 

 

Yes, he could use extra LEDs to indicate whether there is current, while the actuator is being driven, but it isn't really required.

Yep and yep.

 

Thank you so much for the help. I'll try to get it going this week and report back.

[bob_m_54]

Hi Peter, I forgot to ask, what are you using the actuator to drive? Just curious.

[Guest Peter the Greek]

16 hours ago, bob_m_54 said:

Hi Peter, I forgot to ask, what are you using the actuator to drive? Just curious.

It opens and closes nest boxes for our hen flock. I'll post some pics/vids at some point when its finished. Their new mobile home is operational but not yet finished. This is one of the things on the to do list.

[Guest Peter the Greek]

Hi Guys and @bob_m_54,

 

Finally got it installed yesterday, works perfectly. Thank you again so much for your help, much appreciated.

 

The time whilst DIN rail capable, is non standard depth and height....irritating, this'll do for now

 

[bob_m_54]

Glad to hear mate, and yes it was me on that other forum

That is one big chook trailer..

[Guest Peter the Greek]

2 hours ago, bob_m_54 said:

Glad to hear mate, and yes it was me on that other forum

That is one big chook trailer..

Technically speaking it can house 900, maybe 1,000. We've got 700 in this flock to see how the new design goes.

 

Here it is for anyone else who's bored.....the reason, well part of the reason,  I no longer have a HT