# door actuator getting hot any ideas



## discozombie (Jun 21, 2012)

SOLVED...I have solved with the suggestions from the members here, my code had some issues where I was leaving the circuit closed for 1-2 seconds. All good now.... THANKS TO ALL!

I have a 12v door actuator for a monster in a box im building. Im controlling it with an arduino, 4 channel relay board and a PIR. Right now I have the door actuator and a LED connected to individual relays, triggered by the PIR. The entire thing is being powered by an old computer power supply, 5v for the Arduino and 12v for the LED and Actuator. 

The entire cycle runs about 30-40 seconds. The actuator turns on and off about a dozen times in that time frame. I found after running it for several minutes with maybe 30 seconds before I would trigger it each time, the actuator is hot to the touch and smells like its burning out. I have the actuator connected in that it throws vs pulls. On Halloween night with kids constantly coming and going I know it would run a lot.

Any suggestion on how to keep it from burning out? Is the computer power supply putting too many amps to the actuator, Im no expert just a tinker who knows enough to be dangerous.
thanks
DZ


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## corey872 (Jan 10, 2010)

What exactly is 'the actuator' ...is this a solenoid? motor? something else?

Assuming it is designed to run on 12V, it will only draw the amperage its own internal resistance will allow. This is assuming it wasn't designed to run on a lower voltage or have some type of external 'ballast' resistor.

Beyond that, some of the standard things apply... can you lighten the physical load it moves, either by counterweight, spring, redesign of the door, etc?

If it is some type of solenoid, it might be designed for more of an intermittent 'pop' as opposed to a constant push. Some examples of this would be things like a car lock solenoid or door bell. These are meant to go 'click' for the lock or 'ding-dong' for the bell ...and that is it. Sometimes if someone holds the doorbell button down you get a 'ding-z-z-z-z-z-z-z-t-t-dong' ... well the 'z-z-z-z-z-z-t-t-' part is the solenoid heating up due being held on as opposed to a momentary 'blip'.

You say the cycle is 30-40 seconds and the actuator is on/off a dozen times in that period. Though it may make a huge difference if the actuator is on for 1/10 second and off for 3 seconds or vice versa.


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## hedg12 (Jul 6, 2008)

Are you using an actuator similar to this one?Amazon.com: High Power Door Lock Actuator 2 Wire: [email protected]@[email protected]@http://ecx.images-amazon.com/images/I/[email protected]@[email protected]@41qJ0NsNQVL If so, I'd imagine you're exceeding the duty cycle of the actuator. They're not really designed for heavy use like what you're describing. They're great for intermittent scares like small pop ups, though.


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## drevilstein (Sep 17, 2013)

there are heavier duty linear actuators for sale on ebay


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## DarkOne (Oct 16, 2012)

Are you turning it on, leaving it on and then reversing it for each cycle? These actuators have a small motor inside, so if you turn it "on" in one direction and don't shut it off right away after the pushrod reaches it's limit, the motor is still trying to turn, while the mechanics won't allow it. So you may be burning out the motor. Turning the relay on for 300 milliseconds for each direction and low in between has worked for me in the past. 

If you aren't already, using counterweights to balance the load so your actuator is just "nudging" the action rather than actually doing any real work, will help take stress away from the motor.

I have a few projects in mind for these actuators and I think counterbalancing will be the key in allowing larger loads to be moved.

Please post a pic of your project, I'd really like to see it!


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## discozombie (Jun 21, 2012)

I went through my code and found I was leaving the circuit close for 1000 milliseconds in 3 places. I dropped these to 300 per your recommendation DarkOne. I just finished my box last night so I hope to mount the door actuator today and give it a few tests. Im not 100% with the box I made so I may be redoing this project next year. Ill post some pics and video when I get it completed.


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## discozombie (Jun 21, 2012)

hedg12 said:


> Are you using an actuator similar to this one?Amazon.com: High Power Door Lock Actuator 2 Wire: Automotive If so, I'd imagine you're exceeding the duty cycle of the actuator. They're not really designed for heavy use like what you're describing. They're great for intermittent scares like small pop ups, though.


Yep those look like the exact one Im using. If it the actuator doesn't work out Ill go the motor with irregular cam method


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## corey872 (Jan 10, 2010)

Looks like that actuator uses a small motor which likely drives some sort of rack-and-pinion system for the in-out movement. So any time the circuit is 'on' and the actuator is at the end of the travel, you'd basically be drawing what they call 'locked rotor amps' on the motor. Meaning whenever the motor stops moving, the amperage flowing through it gets much higher.

Reducing on time to 300ms is a good start, though I wouldn't be afraid to experiment with even shorter intervals as long as you can still get the desired effect. You might even find that even a momentary 'bump' will get things moving in the right direction and you can cut power at some point during the movement, then let momentum and inertia take over from there to finish the job.


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## discozombie (Jun 21, 2012)

Almost done now. Need to get chains to cover the top and figure out sound. I think Ill use the smartphone for the sounds and put the speakers on one of the relays.


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## Mogui (Sep 8, 2015)

Typically an actuator would be installed with limit switches that cut off power when a final extent is reached in either direction of travel. Some actuator have them built in. Here is a simple circuit I have used in the past with my coffin lid actuator. Note that it has a relay that is used to reverse the direction of the actuator. It will automatically cut power when a switch is reached, and then run it again in the other direction when the relay is changed. A nice, simple method of control.


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