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Discussion Starter #1
I rely on so many of you to guide my prop builds, and this thread will be no different. This year two of my props had motors that failed, and I'm pretty sure it was our fault for asking them to do something they weren't meant to do. I'm hoping that with a bit of guidance, we can set them up correctly when we go to replace them.

The first was our Skeleton Pop Up. When we first made it, we used a throw bar was too short and it would rise up on one side and fail because the skull and PVC pipe were too heavy. It dropped back down and reversed trying to do the same on the other side. Again it would fail because the motor couldn't lift the skull all the way up and over. We used a longer throw bar weighted on the other side and it rolled around just fine. The only problem was we really liked him bouncing back and forth much more than the traditional rolling version seen all over the net. However, as he ran, he would slowly rise less and less. By the time a four hour evening was over, he was just popping half way up on one side. But he still looked great. (What you see in the video is him after about two hours.)


This year, Halloween night, he began to shudder and finally just wound up unable to rise up on one side and he kept bouncing up and down on the other. I'm thinking that I overworked the motor by actually forcing it to use the reverse function it had built in. Is that right? And is there a way that we can put in a new motor that would create the same back and forth without killing the motor? We were using a synchronous motor 50/60Hz AC 110V 4W 5/6RPM CCW/CW. At any rate, all suggestions about how to recreate the look of the prop without killing the motor would be appreciated.

The second motor to fail was our rocking pirate skeleton. He's on a slider rocker, and the wiper motor basically just pushes the slider forward and then as it rounds backward, the rocker pushes back. It worked like a charm, but the poor skeleton rocked really fast, so I took a dimmer switch for a lamp and plugged it into the motor. I just kept reducing the amount of current until the rocker was at a speed I liked. This year, I slowed him WAY down so that he was barely rocking and I think the motor froze up because he was on a dimmer. Jimdkc and J-Man brought up PWM controllers in another post and I'm wondering if that might have been a better choice for controlling the speed of the rocker. Is that a possibility for preventing disasters down the road? Replacing the motor is easy, but I want to make sure that the motor I put in isn't stressed to the breaking point by me slowing it down in the wrong way. Here he is below. Pardon the shaky video, but it's what I had from a couple of years back.


This was his normal rocking speed using the dimmer. The rocking motion I used this year was even slower and he froze up half way through the evening. Any suggestions on replacing his motor and the appropriate way to slow him down would be appreciated. Thanks in advance for all your suggestions.
 

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For the wiper motor, yes a PWM control is what you need. A dimmer switch is not what you want and likely the cause of a burned out motor. You can get the same PWM controllers sold by FP and MG on ebay for around $3.
https://www.ebay.com/itm/12V-40V-10A-PWM-DC-Motor-Speed-Controller-with-Knob-LW/233046489058?epid=25023461478&hash=item3642a737e2:g:qzgAAOSw7U9bXqvR
As for the synchronous motor failing, it was simply over worked. Those little motors are great but they can only handle loads to a certain point before they quit. Sounds like a wiper motor would have been more suited for the tombstone popper.
 

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Discussion Starter #3
For the wiper motor, yes a PWM control is what you need.
Thanks for the response. We have an order in for a few PWM controllers. My guess is that I will need them for a number of props being created this year, including another rocker for our witches' house. I really want to put a skeleton rocking out on the porch that yells, "YOU KIDS GET OFF OF MY LAWN," when kids walk by. But I'll probably settle for just the rocker rocking without anyone sitting in it. I always seem to have ideas that require more knowledge than I have or a larger budget.


As for the synchronous motor failing, it was simply over worked. Those little motors are great but they can only handle loads to a certain point before they quit. Sounds like a wiper motor would have been more suited for the tombstone popper.
It looks like another visit to the local wrecking yard is in order. :) Thanks for the advice. Now if I can just figure out how to keep that same pop up motion in place with a motor that really wants to have him going in a circle, I will be a very happy haunter.
 

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I would agree that forcing that synchronous motor to constantly reverse killed it. I built a small prototype head turning mechanism using adjustable stops. The idea was to have the motor just reverse to make the whole thing very simple. Great idea, but the motor got very hot and did not last long before dying completely. We use the same motors in mechanisms that run nonstop in one direction without fail.

Totally agree with J-Man, you need to use a PWM on your wiper motors. We use them on all of our kits and run them all at a crawl. At shows they run 2 days straight and barely get warm. I’ve personally never encountered a wiper motor burning out. :)
 

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I know a lot of people get junk yard wiper motors but I highly recommend getting new ones from Fright Props or Monster Guts. They're only around $25 and are specifically designed for prop building and no worries about a rusty old motor crapping out. BTW, in case you didn't already know, those PWM controllers are for DC motors only, not for AC motors. Make sure you get the ones that are rated for at least 10A for wiper motors. Also totally agree with Diabolik about the synchronous motor. Setting them up to constantly reverse is not the best choice, linkage that allows the motor to just run in one direction is a much better approach. I have one on my leering skelly and it will run for hours with no problem.
 

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I second the suggestion to use wiper motors for props like these. They have tons of torque and by using a speed controller you can get just about any effect you want. I usually over-engineer (sometimes grossly over-engineer) any prop I make because I want to build it once and not have to futz with it after that. And the last think I want is to be worried about a motor or board overheating and catching fire in my yard.

As far as the motion of the pop-up is concerned I think you may be able to achieve that same motion by using a cam mounted on the motor that is not round (ie like a pear or a snail shell). I would have to sit down with pencil and paper but I think you could do it. Here is a page that will give you some more info: https://www.explainthatstuff.com/cranks-and-cams.html.
 

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Discussion Starter #7
I usually over-engineer (sometimes grossly over-engineer) any prop I make because I want to build it once and not have to futz with it after that. And the last think I want is to be worried about a motor or board overheating and catching fire in my yard.
I am beginning to see the wisdom in over engineering. So much of what we do is based on what we see others do, with a slight twist to try and make it our own. Sometimes I think it's sheer luck that keeps those smaller motors running large props. Having never been particularly lucky, I'm thinking the path of "too much is never enough" might be better suited for our props.

As far as the motion of the pop-up is concerned I think you may be able to achieve that same motion by using a cam mounted on the motor that is not round (ie like a pear or a snail shell). I would have to sit down with pencil and paper but I think you could do it. Here is a page that will give you some more info: https://www.explainthatstuff.com/cranks-and-cams.html.
Thanks for the link. I've seen cams used in monster in a box props, but had never even considered how it might be used elsewhere. Below is a video that shows what I was doing.


As you can see the little motor fails to push the skull up and over the top into the traditional arc, so it drops back down and repeats the process. It looks so much better than letting him go around in a circle, but it also burned out the motor after two years of rather limited use. If I add a counterbalance to the skull, the motor probably wouldn't burn out, but it would go in the complete arc that looks like every other pop up skull. Do you think a cam can reproduce that up and down back and forth movement?
 

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Discussion Starter #8
I would agree that forcing that synchronous motor to constantly reverse killed it. I built a small prototype head turning mechanism using adjustable stops. The idea was to have the motor just reverse to make the whole thing very simple. Great idea, but the motor got very hot and did not last long before dying completely. We use the same motors in mechanisms that run nonstop in one direction without fail.
Well, there you go. I actually followed a tutorial that suggested doing exactly what you did for your motor by putting nails in the prop to stop the motor and head it the other direction. I thought that since our motor was doing it just naturally, it would be okay. (Hence me being here asking others with far more experience what they do.) That is one of the downsides to watching YouTube videos. Some people post how they made their project, but never return to delete or update the video when the find out that what they created failed after a few weeks of use.
 

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Discussion Starter #9
I know a lot of people get junk yard wiper motors but I highly recommend getting new ones from Fright Props or Monster Guts. They're only around $25 and are specifically designed for prop building and no worries about a rusty old motor crapping out.
We will seriously contemplate paying the extra for new motors from Monster Guts. It's tough to pony up $45 for a motor (motor plus shipping and handling) when we get them at the wrecking yard for 15 bucks a piece. We have some very nice guys who laugh their butts off every time we tell them why were there, but they always give us a discount because we're buying stuff that no one else wants.) None of our other wiper motors have ever failed, but you are right they do look pretty nasty compared to the nice shiny new ones. I think we'll save up and buy a new one so that it can go head to head with the wrecking yard motors. Somewhere down the line we'll share the data on who lasts longer. :)

BTW, in case you didn't already know, those PWM controllers are for DC motors only, not for AC motors. Make sure you get the ones that are rated for at least 10A for wiper motors. Also totally agree with Diabolik about the synchronous motor. Setting them up to constantly reverse is not the best choice, linkage that allows the motor to just run in one direction is a much better approach. I have one on my leering skelly and it will run for hours with no problem.
I purchased the DC, 10A PWM controllers for the wiper motors. That was because a tutorial I looked at about installing them with a wiper motor had a link to the right kind of unit, not because I knew what I was supposed to have. You can feel safe in assuming that I know nothing about any electrical subject and that I appreciate every bit of advice you give.

That said, on to another part I'm ignorant about. Is the only way to have a slow rotation for the synchronous motor to buy one that has a slow rotation? I want to make a floating candelabra that is essentially a mini version of a crank ghost. But I want it to move very slowly. I know the synchronous motors come at various rotations per minute, is that the way I get a slow movement? I have so many questions... hahaha
 

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That said, on to another part I'm ignorant about. Is the only way to have a slow rotation for the synchronous motor to buy one that has a slow rotation? I want to make a floating candelabra that is essentially a mini version of a crank ghost. But I want it to move very slowly. I know the synchronous motors come at various rotations per minute, is that the way I get a slow movement? I have so many questions... hahaha
Here ya go, 12VDC synchronous. You can use one of the PWM speed controls on it.

https://www.ebay.com/itm/CHANCS-Synchronous-Motor-TYC-50-12V-DC-2-5-3RPM-4W-CW-CCW-Low-Noise/163399535120?hash=item260b5f0a10:g:Ib4AAOSwnN5bdTlX
 

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Fright Props wiper motors are $25 and $10 for Priority shipping for one. If you order more than one you'll save on the shipping. Another plus with these is the wiring is consistant, with junkyard wiper motors, the wiring can sometimes be a headache to figure out. In regards to your tombstone popper action, you could use a wiper motor with a Picovolt controller to program that reversing action. A bit more expensive than the $5 synchronous but sometimes there's really no "cheap" way to do things if you want it to last.
 

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I would agree that forcing that synchronous motor to constantly reverse killed it. I built a small prototype head turning mechanism using adjustable stops. The idea was to have the motor just reverse to make the whole thing very simple. Great idea, but the motor got very hot and did not last long before dying completely. We use the same motors in mechanisms that run nonstop in one direction without fail.

Totally agree with J-Man, you need to use a PWM on your wiper motors. We use them on all of our kits and run them all at a crawl. At shows they run 2 days straight and barely get warm. I’ve personally never encountered a wiper motor burning out. :)
It depends on the motor too. I ran a prop all month this year, 6-8 hours a night, with a synchronous motor that reversed and it did just fine, never stalled, never had a problem. Of course, it had a very light load on it so it never got warm. Some synch motors are better than others at handling reversing. Some, like the ones sold by Frightprops I think, say they don't reverse at all. Or maybe it was someone else, I don't recall.
 

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Discussion Starter #13
Thank you so much. It never occurred to me that there might be a DC version of the motors out there. I don't think often outside the box when it comes to things I don't understand very well. I'm great at creating fun props in my mind, but I always have to have help from folks to take them from the drawing board in my mind to the real world if they involve motors or electricity. On the plus side, one day I will be able to post props here that I think anyone would be proud to show off, and there will be plenty of people who can say, "I helped with that one." And, that's one of my favorite reasons for loving this site. :)
 

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Fright Props wiper motors are $25 and $10 for Priority shipping for one. If you order more than one you'll save on the shipping. Another plus with these is the wiring is consistant, with junkyard wiper motors, the wiring can sometimes be a headache to figure out. In regards to your tombstone popper action, you could use a wiper motor with a Picovolt controller to program that reversing action. A bit more expensive than the $5 synchronous but sometimes there's really no "cheap" way to do things if you want it to last.
Our budget will let us splurge on a couple of motors, but the picovolt is a bit high end for us. So, the search will go on to see if there's a way we can get that head to rock back and forth. I am going to experiment with the cam suggestion from JW Halloween. If nothing else, I guess we can soldier on with a grave popper that looks like all the others and just rolls around the top. He'd at least be new to our neighborhood. But I think you've won us over on the idea that working with a new wiper motor has its benefits. :)
 

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It depends on the motor too. I ran a prop all month this year, 6-8 hours a night, with a synchronous motor that reversed and it did just fine, never stalled, never had a problem.
Our first year, the pop up skeleton worked great. He was out every weekend for three days and on Halloween night bobbing his head back and forth without a glitch. It wasn't until this year after three weeks out on tour that he decided to give up the ghost on Halloween day. I guess we should have paid more attention to the skeleton union's demand for longer lunch breaks. :p
 

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Honestly, considering what these motors cost, have a couple of extras on hand. I buy them by the dozen.
hahaha..... okay. I admit that thought crossed my mind. One of the companies I worked for had multiple cogs that they considered disposables. They were replaced as soon as they didn't perform as expected. Most were my managers, but occasionally it was actually a coffee pot or the like. I don't have a problem replacing a pair of tennis shoes that wear out after six months, I don't know why I struggle with a five dollar motor burning out after two years. If I can prove that their death won't burn down the place, I may well replace them as frequently as needed for the effect I want.

That said, Cephus 404, if you have a link to the motor you used all last season, could you pass it along? It would be nice to at least start off with a motor that has a history of lasing longer than some of my managers did.
 

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Another option to a wiper motor and also a cheaper option is a power car seat motor. You would still use the same power supply as a wiper motor and can use a PWM with it. Has nearly the same torque as a wiper motor as well. Only big issue with a car seat motor is the shaft is non standard so you can't just use normal nuts to attach an arm to it. You would have to either use couplings with set screws or JB Weld nuts that are just slightly bigger than the shaft to the shaft. The shaft is also fairly long, but can be cut shorter if needed.

I have been using a car seat motor for my stirring mechanism in my cauldron for the past 3 years. Usually run it at least 6 hours non stop a day for at least 2 weeks a season. Have not had any issues with it at all, even while running in rain and or snow.

This website currently has them on sale and shipping cost is based on how much you spend. If you bought one of them the shipping cost would be $7.50, but if you bought say 5 motors the shipping cost would be $10.95.

 

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Another option to a wiper motor and also a cheaper option is a power car seat motor. You would still use the same power supply as a wiper motor and can use a PWM with it. Has nearly the same torque as a wiper motor as well. Only big issue with a car seat motor is the shaft is non standard so you can't just use normal nuts to attach an arm to it. You would have to either use couplings with set screws or JB Weld nuts that are just slightly bigger than the shaft to the shaft. The shaft is also fairly long, but can be cut shorter if needed.

I have been using a car seat motor for my stirring mechanism in my cauldron for the past 3 years. Usually run it at least 6 hours non stop a day for at least 2 weeks a season. Have not had any issues with it at all, even while running in rain and or snow.

This website currently has them on sale and shipping cost is based on how much you spend. If you bought one of them the shipping cost would be $7.50, but if you bought say 5 motors the shipping cost would be $10.95.

Thanks for the suggestion. We're branching out into areas using different motors that need a bit more torque than the smaller motors we use for our tombstone popper, and those look like a great middle ground between the reindeer motors and the wiper mothers we have. We invested in a set of three smaller motors that said they were high torque for the pop up skeleton and he's apparently very happy with what we bought. He lasted the season bobbing up and down for about a week. Best of all, he did it while both going around the circle sometimes, and back and forth other times. His random rotation made him just that much more fun. Is it worth it to us to have him behave that way even if we have to replace his motor every other year? YEP!
 

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Thanks for the suggestion. We're branching out into areas using different motors that need a bit more torque than the smaller motors we use for our tombstone popper, and those look like a great middle ground between the reindeer motors and the wiper mothers we have. We invested in a set of three smaller motors that said they were high torque for the pop up skeleton and he's apparently very happy with what we bought. He lasted the season bobbing up and down for about a week. Best of all, he did it while both going around the circle sometimes, and back and forth other times. His random rotation made him just that much more fun. Is it worth it to us to have him behave that way even if we have to replace his motor every other year? YEP!
What type of motor did you buy? I was thinking of doing a tombstone popper for next year. I was thinking of doing a grave digger and a breathing grave with the motor I posted above.
 
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