I bought this actuator in May of 2015. I’ve played with it off and on since then, trying to get it to work. I finally had it working last night. I ran a 6 channel transmitter to 4 relays. 2 relays at a time were activated by one of the channels… it closes the circuit and 12V DC is sent to the actuator. 2 relays were set up for normal polarity (positive going to the positive cable on the actuator, ground to gorund)… the other two relays were set up with reverse polarity. Only two of the relays were ever activated at a time, meaning current wasn’t flowing in both directions simultaneously. The transmitter activated two of the relays to extend the actuator and the other two to retract it. I’ve hard wired polarity and reverse polarity for tests before and everything seemed fine.
I had this working once last night… the transmitter sent the signal, relays fired, the actuator extended and retracted. This morning I get up to set up the other relay set for the other motor I have in the project. I fired everything up and the actuator will only extend. It won’t retract. The transmitter transmits, the Arduino shows a good signal and fires the right pins… the relays trigger… I hard wired the reverse polarity to my 12V source and nothing.
Has anyone else played with this kind of actuator and seen this behavior? Is there anything I can do to fix it or am I just out the $150 for it?
Thanks!
Rick
You’d need to show the electrical setup / wiring. You should only have one relay active for one actuator at a given time.
What you really need is a DPDT relay robotshop.com/en/12-vdc-dpdt-relay.html
I mean, the DPDT relay is essentially what I built, right? I just couldn’t find one that triggered off of a 5v signal like these did.
Here’s the wiring diagram.
drive.google.com/file/d/0B_TrOY … sp=sharing
Not sure why you need four relays; one relay should cause the actuator to extend, leaving the second relay not powered.
Sending a signal to the second relay should cause it to retract, ensuring no signal is sent to the first relay.
How do you reverse the polarity with just two relays though? I tried a few different wiring schemes to get that to happen… I could only interrupt the positive or ground with one relay though… the other had to be hard wired… I couldn’t figure out how to reverse the polarity with just two relays if one side of the circuit was connected directly to the 12V source.
One relay needs to provide reverse polarity. Would need to think it through a bit though given that you have four relays connected to one board. Not sure if GND is common to all.
Thanks… I did try the two relays first… I just couldn’t figure out how to wire it so that I could switch the polarity using just two relays. Everything I came up with closed one side or the other permanently. The 12V ground and 5V ground are different… the 12V Grounds are all common… I could try different groundings but I think I run into the same issue… dunno, I’d have to draw it out.
You also need to confirm that both relays are not receiving a signal simultaneously.
Yup, there are lights on all 4 relays… the correct ones go on and off with the correct inputs from the transmitter… I’m also outputting the Arduino pin statuses to the screen and can see that the pins are activating and deactivating correctly… just as a backup to the LEDs on the relays. I can take a video of it tonight and post it.
I just didn’t know if there was something within the actuator itself that I could do to get it to go back in once it’s fully extended… I could try extending it to its limit and then retracting it… maybe that would “reset” it somehow… but if that doesn’t work, I’m kinda out of luck.
Can you show us a wiring diagram of how you wired it for use with only two relays?
I don’t remember the different variations I tried… none of them worked though. I know both wires on the actuator were split and each was sent to ground and to the relay though. To complete the circuit, you have to ground the other wire. So for normal polarity, positive on the actuator goes to positive on the 12V source… negative to ground. For reverse polarity, Positive on the actuator has to go to ground and the Negative wire has to go to the relay (12V source).
In both cases, you have to ground one or the other wire… since whichever wire is being linked to the 12V source is also permanently grounded (for the other polarity), the electricity will just flow to the ground, not through the actuator. That’s why I switched to 4 relays, so I could control which one is grounded at the same time that I control which one is powered.
I got this working… I had a bad relay. It was passing current through on two of the relays but not on the other two… I pulled the wires last night and tried to retract the actuator and it didn’t work but it seemed to be ok today.
Thanks for all of the input. If you figure out how to wire it for reverse polarities with just 2 relays, I’d love to hear about it also… It would cut a whole relay board out of my design 
Here’s a video of it working if you’re curious… the wiring’s a mess for now though
drive.google.com/file/d/0B_TrOY … sp=sharing
Excellent. For future reference, you could have gotten away with a DC motor controller which accepts RC input; it allows you to control both speed and direction of a DC motor (the linear actuator you have is essentially a DC gear motor).
I tried an LAC to begin with but I burned it out. The actuator pulls 4.6 amps and the LAC only handles 3. I’ll take a look at the DC motor controllers in the future though. Once I get this setup hooked up, I have an idea for another one
