motors burning out

[taterking]

I'm getting desperate for  a solution to my project. thought I would describe and see if anyone had any thoughts. In my project i am using standard 12 volt car door lock actuators.  their speed an power are perfect for my project.

https://www.amazon.com/InstallGear-Universal-Power-Actuators-12-Volt/dp/B00CZBQCR2/ref=asc_df_B00CZBQCR2/?tag=hyprod-20&linkCode=df0&hvadid=312697294768&hvpos=1o1&hvnetw=g&hvrand=11731719315907656674&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9021655&hvtargid=aud-799711277694:pla-571734903516&psc=1

however after about a half hour of consistent use the motors warm up and burn out. what do i do in this situation? after cutting one of these open. inside there is simply a small geared down cheap rotary motor that is sealed in the plastic casing.

I dont know much about motors.

ive considered ordering new ones and cutting the plasic off the motor only and attaching a small cooling fan. is this a silly idea?

is there something similar to a door lock motor that would be more heavy duty?

is there somewhere to order parts to create something like this that would be more heavy duty?

any thought would be appreciated. I dont know much about this sort of thing.

[Blackfin]

Are you always driving the motor? Or do you power it only for the few moments it takes for the actuator to extend or retract?

If you're always driving it one way or the other it will stall when it reaches the stop and at that point will draw enormous current and overheat.

[SteveMann]

Without knowing what your project is, how can anyone recommend other options?

Door lock actuators aren't designed for more than intermittent use, so if you are running them continuous or even often, they will get hot to failure, as you have figured out.

Fan:  I would be concerned that the body contributes to the physical integrity of the actuator, but a fan could extend the actuators life, but I suspect, not by much.

[sayHovis]

I'd search the likes of digikey or mouser for a linear actuator and look for "duty cycle" to see if there's one designed for continuous use.

If you end up needing something from eg Firgelli you will need deep pockets. But I guess part of the cost goes to providing a decent duty cycle, where a car door lock's only supposed to be actuated at most after a few minutes rest and then not too often. My car's typical journey might mean unlocking, getting in, locking, driving an hour to work, unlocking, getting out, locking; do the same 9h later. A commercial quality actuator that would open and close a baffle say on a conveyor to direct parts, all day long, will not cost 10 bucks for 2.

But then you didn't say what your project requirement is.

[TomGeorge]

Hi,

however after about a half hour of consistent use the motors warm up and burn out. what do i do in this situation? after cutting one of these open. inside there is simply a small geared down cheap rotary motor that is sealed in the plastic casing.

There is your problem underlined.
You are using "InstallGear Universal Car Power Door Lock Actuators 12-Volt Motor "

They are designed for INTERMITTENT use, how often do you operate your door locks.
They will be designed for a price and operating function, probably ONE operation an HOUR.
They will have no built in cooling, and the motors with the gearing are designed to get warm with INTERMITTENT use but not CONSISTENT use.

Sorry but a wrong choice of device.




Tom...

[saildude]

I would think more than once an hour - some of my trips - unlock & load the car - drive down the street an locks a couple of minutes later at 9mp - finish trip and park at the library or post office in about 5 minutes - unlock & unload then lock again - - but as noted above not continuous

Welcome to the real world of design - or why I had a 50 hp pump and not a 25 hp water pump - on one plant I helped design

[taterking]

my project is a musical one. so the actuators are used in combination of sticks and pedals to strike persussion instruments. they can be triggered up to a few times a second. there is an inevitable brief point of stall when the motor reaches its max extension.   i am fully aware that I am using these motors for more that what they are indented for but cant find a better solution. the motors work pefectly for up to a half hour till they heat up and fail. i'm pondering on if custom heat distribution would be my direction? could i find somewhere to order parts or gears to hand make something bigger? possiblely higher voltage motors to run at less volts? my problem is i cant locate anything allready out there more appropriate for my project. how to make one more robust for my task?   I am simply planning on going about my problem with  a trial and error apporoach. just looking for any info i can grab first?

[sayHovis]

You presumably aren't the first person to do such a (or similar) project: what actuators do other folk use?

[saildude]

Would some sort of a plain solenoid work - many of them have high duty cycles and designed for heavy use.  But then you might need some sort of shock absorber  to help control the speed  of the actuator - or as suggested above use what someone else is using

Good luck - sounds interesting

[wvmarle]

Are you sure there's a motor in those door actuators? Not a simple electromagnet?

Maybe a servo can work. They're often used for linear actuator applications, but they're noisy. Maybe not good for your music.

As it's for moving sticks up and down without apparent need of control of the strength of the hits or position control, indeed a solenoid comes to mind. Get one that's designed for continuous use. They may still get hot, but that's OK as long as you offer free air flow around them. Or if you have to activate them for longer time continuously consider PWM: a pulse at 100% to activate the thing; dropping do lower duty cycle to hold in place.

[dave-in-nj]

if you are burning the existing units out, you can safely dissect one to see if you can put lots of large holes in the cover to allow for air flow.   

what bothers me more is the back EMF and no idea what you are doing for a driver.

if you are using them rapidly, have you ever determined the frequency ?

It might be possible to put a resistor between the power supply and add a capacitor
that way, when you want to energize the coil, you use the energy in the cap, and it drains rapidly.
knowing the fastest cycle rate would allow some calculations to figure the capacitor and the resistor sizes.

just tossing out an idea.

[MorganS]

Sounds like a fun project. 

I was going to suggest the same as Dave: cut away as much as possible of the plastic case to get cool air in.

Show us your current driver circuit. And the code. Are you fully de-powering them when they are not actively moving?

[taterking]

I like the idea of a selenoid and considered one from the beginning but was unable to locate one the right size for my project. seems the tiny ones for tinkering are easy to find. anyone know of any meduim sized selenoids with a draw somewhere in the range of 3-5 amps?

in the meantime I think I am going to cut away the plastic and add a cooling fan this week since i allready have an extra one at the house... see if that helps.

I did open one up and there is in fact a small rotary motor that slips out with a small gear on the shaft. now im cotemplating on how i could get the gear off this little motor and onto a slightly bigger motor?

[Paul__B]

I did open one up and there is in fact a small rotary motor that slips out with a small gear on the shaft. now im contemplating on how i could get the gear off this little motor and onto a slightly bigger motor?

Sorry, but now you are talking engineering and I will suggest to you that it isn't worth your time - or anyone else's for that matter.

Can't offhand suggest a suitable device, but clearly these are not the one. 

[MorganS]

The next step up is going to be RC hobby servos. A little overkill for your application since you don't need accurate positions. But I think that is the easiest way to buy actuators in that size range.