198 replies to this topic

[Mad Hatter]

really cool can't wait to see the finished project!

[ForgotToGrowUp]

Thanks for the comments.

I figured out how I was going to be able to fit the drive gear in for the brake run, which was tricky because the track under it makes it tight and I didn't have a full box to set the gear in. I built this and was going to put it into the structure in place of what is there.





But I figured I should let it run and put some load on it before I built a lot of stuff on top of it. The weirdest thing is happening. It will all run smoothly for a while and then something gets out of synch and it either locks up or one of the worm gears will pull off the motor shaft. I thought I narrowed it down to a fluky power pack because it seemed like swapping them made the problem move from motor to motor. But after swapping out the suspected power pack I let it run for a while and it happened again. Sometimes it will run for only a few minutes other times it will go for almost 30. But eventually it locks up.

Gonna have to replan the whole motor set up. Might stay away from the backwards running motors, maybe they are knock offs or something and run at slightly different speeds??? Maybe having 2 pairs drive the yellow gear instead of one shaft is the problem? Doesn't seem like it though, seems like the problem is between a pair of motors on a single white gear.

I've seen Gump put 4 electric motors on a single black rod but that looks like the max and even with that the rod is not long enough to be supported on both sides of the white gears. I used 2 motors on my last coaster but this one will have a longer lift, so more chain drag and will have heavier trains.

Any one else have problems like this?

Any create ways to combine motors?

Also is there a better way to put electric motors in a granite box than what I am doing?

Thanks.

[ickus305]

I have had this issue.

Those motors that run "backwards" their polarity is simply the opposite (I have several like that), but I try to keep the same motors working in tandem there are 3-4 different variations on the motors (when I have mixed the motors that are powering one section, I have had the stalling issue), and also when I talked to K'nex the motor specs vary by almost 500rpm(I will see if I can dig up the e-mail, it was from almost a year ago). I have in the ballpark of 40 motors and some pairings just simply do not work because the variations are too much.


A few suggestions for fixes.

1. add a second yellow crown gear opposite the first one (just to help balance things) or add a rod that goes between the red gears from the yellow crown gear so it isn't twisting.

2. instead of mixing and matching the motors, use 4 of the same motors from the start, and then reverse the polarity on two of the power packs (I did this for my wooden station, and have had no problems, simply cut the wire and re-solder it)

Hope that may help some.

[Snake]

I think the problem may be that 1 motor is pushing on the gear away and the other is pulling the gear in. Try using 4 normal spinning motors.

[ForgotToGrowUp]

Thanks ickus, that makes sense. did you have to test a bunch of motors to find ones that worked well together or did you just go by the looks of them. I have 9 of them and have not kept track of what came in what boxes. Some came without boxes. Do you use the power packs or a different power supply. I was thinking of getting a power supply that could drive all of them (expect most hobby shops sell them)

Snake, the backwards running motors act on the gear the same as any other motor that was mounted the other way. The issue has to be rpms or slight differences in the worm gears.

[Jogumpie]

I think that Ickus explained it well. It's an issue I may encounter, too. Especially since my 8 new motors have a different color than the other 10 motors.

[Maxlaam]

I've never noticed such a difference in my motors, really odd. I usually double up my lift motors. Never had things lock up because of RPM variations in my motors. I've burnt through a few adapters though, wonder how the motors will behave on Phase3.0.

About the model so far:
It's truely amazing. I really like how you build it on a table with green cloth on it, surely looks like a real constructon site with all those pieces scattered around. Not to mention the awesome way this ride arises, it almost looks like you would construct it like a real coaster.

[coastercrazy10]

Another thing to look out for is breaker limits. The power packs for the electric motors have electronic components built in in so they won't be the current-drawing device that trips your circuit breaker. In other words, if one of them pulling their maximum current would trip the breaker, that power pack would pull only what it could in order to prevent that trip. I ran into problems with 4 motors running out of sync but 3 running fine (no matter which three I used), which means that they're just trying to pull too much current. If there's anything else plugged into the same outlet (or outlets nearby, most outlets in a room share the same circuit breaker), try unplugging them to make sure you're not maxing out the available current for that breaker.

Looking good by the way. Building it on the table gives it such a classy look. And I never thought I'd say this, but the dense supports really do this ride favors. It looks fantastic.

-Ben

[ForgotToGrowUp]

Max, definitely am building this like a real construction would take place. It's really the only option with something that crosses over itself as much as this.

Thanks CC10, could be a possiblity especially since I have them all ganged up on a single extension cord and it is plugged in to an outlet on the same circuit as the home entertainment system. I doubt that the power pack/tranformer is that intelligent, but they may have voltage cutouts or heat cutouts. If you start drawing too much current through something like the extension cord there will be a voltage drop. Definitely something to consider.

Has anyone used a computer power supply? They provide 5V and 12V outputs and are pretty cheap and support a fair amount of wattage.

[Maxlaam]

I ran into problems with 4 motors running out of sync but 3 running fine (no matter which three I used), which means that they're just trying to pull too much current. If there's anything else plugged into the same outlet (or outlets nearby, most outlets in a room share the same circuit breaker), try unplugging them to make sure you're not maxing out the available current for that breaker.

Never had those problems before, I measured the amps of a motor without any load on it, draws about 80mA, I can see this go up to about 500mA if you are really trying to get everything out of it, but from experience I've never had any problems with a 300mA powersupply. I've had multiple motors run at once as well, this was at home but also expo's.

So far we only got hooked up to the fairground's aggregate 3 times because the buildings/tents didn't have their own power outputs. So that's not a proper comparisson as those funfair rides draw much more than 2A's, more than enough for our expo models
But where we did draw our power from the wallsockets, we didn't ran into any problems and besides motors we had lightbulbs, LED's and music players running at the same time.

I don't get how 4 motor's can trip a breaker...

Has anyone used a computer power supply? They provide 5V and 12V outputs and are pretty cheap and support a fair amount of wattage.

Floris2Burn was the first one from who've I've seen a PSU connected to some K'NEX motors. Furthermore we have TheSUCKCrew, Jogumpie and me working with them. Gump got it working properly. I'm almost reaching the testing phase. It's not a bad idea to work with a PSU, mostly because of the different voltages, and they can handle quite some A's

[pkiknex25]

Max, I think Ben means in combination with other household items. His situation just happened to reach the max at 4 because of the stuff in his basement.

[ForgotToGrowUp]

Good point Max, you are right, these little motors don't draw anywhere near enough current to be a big issue.

Do you know what the designation on those plugs that go into the motor is? I am sure they are pretty cheap and it would be good not to cut up the power packs that came with them.

[Jogumpie]

Then again, this 80mA to 500mA rating is based on the 12V voltage. The adapters that are plugged into your extension cord / wall socket work on 120V (USA) or 230V (Europe) and ask for fewer amps.

[coastercrazy10]

Max, I think Ben means in combination with other household items. His situation just happened to reach the max at 4 because of the stuff in his basement.

This. Each of those power packs are rated at 500 mA. I also had a dehumidifier, TV, my laptop, router, modem, and several other things hooked up on the same breaker. Most household breakers are 10 or 15 Amps in the US AFAIK, and my laptop and the dehumidifier pull several Amps each. It's just the combination of things, not the four motors themselves. You should be able to easily run over a dozen on a single breaker if that's all that's plugged in.

Also at an expo, you've got industrial electrical work and your breakers are going to have higher limits. An expo would be the last place to experience a phenomenon like this.

-Ben

[ForgotToGrowUp]

My house is old so there is not a lot of separate circuits and almost all are only 15 amps and I have a ton plugged into my living room outlets. Consider I had the following things all turned on; a 1200W stereo reciever, a 46" TV, a cable box/DVR (known power hogs), a laptop computer, a cable modem, a wireless rounter, an iphone charger, a couple of lamps, a BluRay Player and Wii on standby, AND the 4 motors all on the same circuit it is a distinct possibility.

... but I still think ickus' theory is most likely

[Jogumpie]

A 12V motor pulls at maximum 350 mA from its transformator. Scaled to your mains (120V) that is 35 mA for each motor that is pulled from the wall socket. I can NOT imagine that 4 motors can cause problems, Ben.

[floris2burn]

A circuit breaker is not going to trip because you add this tiny extra load on it.
Circuit breakers trip instantly when you create a short-circuit. But when you pull almost, or even more than the maximum load of a circuit breaker, it'll take an hour or even more before it'll trip.

Also, a 12V motor draws about 350mA, which means it's about 4.2Watts. Convert this to 120V for American circuits, and you get a current of about 35mA. That's 0.233% of a 15A rated circuit breaker's maximum load. (Sorry for using your numbers Jogumpie.)

Also, consider using PSU's as Maxlaam said, you just need one socket to power many motors with one PSU. Just be careful.

[TheSUCKCrew]

Wow. I lol'd.

[Snake]

If the top motor spins slower than the bottom it could push the worm gear off.

[floris2burn]

I think the extra drag just slows down the faster motor. They're not that powerful.