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(Topic ID: 134925)

Cooling flipper coils by aluminium heat sinks or PC fans


By Zora

5 years ago



Topic Stats

  • 47 posts
  • 22 Pinsiders participating
  • Latest reply 4 years ago by vegemite_nick
  • Topic is favorited by 7 Pinsiders

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    LOTR_flipper_fans.jpg

    #1 5 years ago

    I plan to cool my LOTR flipper coils by aluminium heat sinks if possible. Has anybody realized such a passive cooling system and can propose a concrete model and source for this sink? Is a heat sink sufficient for cooling of a coil? What do I have to take care of when installing a sink?

    Alternatively, if this does not work, I would use a PC fan (which possibly is the more common approach), although this would mean that I have to take energy from somewhere. Which fan models (seize and voltage) do you use? Where do you get the energy from in the pinball?

    Thank you and best regards

    Eckhard

    #2 5 years ago

    Is it really needed?

    #3 5 years ago
    Quoted from bigd1979:

    Is it really needed?

    I guess if you trap the balls on flippers alot

    #4 5 years ago

    I plan, someday, doing the fans. I have the heat sinks, ones from tower hobbies that are intended for rc car motors and fit around coils perfectly. While they do improve, there is still a change from the start until deep in a marathon game.

    It's much better, but I want complete consistency throughout, So I will be doing the fan mod when I bet around to itm

    #5 5 years ago

    Regarding the heat sinks: which concrete model/part number did you use and how did you fix/install the sinks?

    Thanks for your feedback

    Eckhard

    #6 5 years ago

    I tried the RC car heat sinks. Unfortunately, flipper coils exert a lot of vibration and the alum shorted one of the coil windings. I ended up going to pinball life's stronger Lotr coils. Much better.

    #7 5 years ago

    I wrapped mine up with electrical tape before hand, and secured them with plastic ties. They have held strong for two years without movement of issue.

    #8 5 years ago

    I've used a single 80mm fan tie strapped to the wires blowing air into the flipper coils. I used this on batman forever where the flippers tended to get worse the longer the game was played. This solved the problems utterly.

    #9 5 years ago
    Quoted from markmon:

    I've used a single 80mm fan tie strapped to the wires blowing air into the flipper coils. I used this on Batman Forever where the flippers tended to get worse the longer the game was played. This solved the problems utterly.

    I did the same with a TSPP i had on location a few years ago. It really did help keep the flippers cool when operated for long periods of time.

    #10 5 years ago

    If you find the need for flipper coil cooling, heat sinks are one way to go.
    However, a fan is a far better solution.

    #11 5 years ago

    I'm on mobile right now but if you look at my post history in the lotr member thread I have some pictures of how I mounted my fans. Lotr have an aux power port in the front of the cab you can get 12v from and use computer fans. They are silent fans so you can't hear them at all. I've had quite a few marathon games on them and never had a problem since installing the fans. I've done it on both lotr and tspp.

    #12 5 years ago

    Who will be the first to liquid cool them?

    Phase change?

    #13 5 years ago

    OP, you should have some thermodynamics experience, at least some formal training (Wikipedia does not count) and document test data before determining the next steps.

    #14 5 years ago

    After 15-20 minutes the flippers on my standard coil LOTR SE would get noticeably weaker. Tried heat sinks (held on with thermal tape and a zip tie), which added about 10 minutes of full power time. Finally in addition added a pair of large fans left over from a computer case that did not need them, mounted on some custom brackets, and that really did the trick: Full power for hours of play.

    I ran some wires to the backbox, and since I have a ColorDMD, I was able to tie into the aux power pass-thru on that board, but you can just run back to the accessory connector in the cabinet front (like the colorDMD already does).

    LOTR_flipper_fans.jpg

    #15 5 years ago

    I didn't realize this was actually a thing. What's the reason for the loss of power? Is it the coil heating up, expanding, and squeezing the sleeve/plunger harder?

    #16 5 years ago

    The coil is heating up. LOTR is apparently way worse than any other game. I had a TSPP and never had problems, but I've heard it a million times about LOTR.

    #17 5 years ago

    Yes multiple people have used fans to solve the issue, it works great. It also solves the problem people complain about by using the more powerful coils, which is that they are extremely powerful at first and then get down to a reasonable level after they warm up. These are the exact same, not too powerful and not too weak, all the time. If you look at the lotr valinor video on Youtube they mention in the comments about using fans on that game as well. Here's how I attached mine using zip ties. I'd recommend something like that vs permanently screwing something into the playfield. This way if I want to remove them it's a matter of snipping two ties. This is TSPP but as I said earlier I did the same on both TSPP and LOTR.

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    #18 5 years ago

    Thank you so much for your comments and pictures. I understand that a heat sink lowers the heat Problem a bit, but the fan solutions seems to be favourable.

    Algum 1,2,3 and Brad 808, as I am not very skilled in electrical issues, would it be possible to send a picture of the concrete power supply for the fans in the LOTR. Algum1,2,3, you mentioned the assessory connector in the cabinet front; where/what is that? I think the fans come with 3 pole wires.

    Regards

    Eckhard

    #19 5 years ago
    Quoted from Wolfmarsh:

    I didn't realize this was actually a thing. What's the reason for the loss of power? Is it the coil heating up, expanding, and squeezing the sleeve/plunger harder?

    Sterns 5020 coils are strong but small and can hear up even with eos working correctly. I've experienced it with lotr, batman forever, acdc (my first one not this one), and 24. The games that use 5032 coils seem better but those are weaker coils.

    #20 5 years ago

    It's because there is constant flipping. If you are up top going into pops, your flipping around the lane changers, any ramp shot or inlane return, you are flipping for the KEEP letters, and that's up top of already epic flipper action with a lot of multiball play.

    #21 5 years ago

    I would love to see a mod which will drastically reduce, the carbon dust.

    #22 5 years ago
    Quoted from Zora:

    Thank you so much for your comments and pictures. I understand that a heat sink lowers the heat Problem a bit, but the fan solutions seems to be favourable.
    Algum 1,2,3 and Brad 808, as I am not very skilled in electrical issues, would it be possible to send a picture of the concrete power supply for the fans in the LOTR. Algum1,2,3, you mentioned the assessory connector in the cabinet front; where/what is that? I think the fans come with 3 pole wires.
    Regards
    Eckhard

    It you look at my last picture the aux power connector is the one I'm holding with black, red, and gray wires. I can't remember off the top of my head which two pins are for 12v. Do you have a multimeter? If so it'll be easy to figure out. The fans won't have the same type connector so you'll need to come up with a way to connect the power wires for the fan to the aux power. I happened to have an extra aux connector so I cut that and spliced the wires into it. I would recommend doing the same so that you are not permanently altering your machine in any way.

    #23 5 years ago
    Quoted from markmon:

    Sterns 5020 coils are strong but small and can hear up even with eos working correctly. I've experienced it with lotr, Batman Forever, acdc (my first one not this one), and 24. The games that use 5032 coils seem better but those are weaker coils.

    The inrush current is what's making them heat up, but what's the scientific explanation for why they lose power? Heating wouldn't effect the coil operation electrically until it failed, unless I'm missing something.

    Is it the expansion from heating that causes more friction?

    #24 5 years ago
    Quoted from Wolfmarsh:

    The inrush current is what's making them heat up, but what's the scientific explanation for why they lose power? Heating wouldn't effect the coil operation electrically until it failed, unless I'm missing something.
    Is it the expansion from heating that causes more friction?

    I believe the coils heating up softens the sleeves, in turn causing increased friction.

    #25 5 years ago

    Magnetic flux density (B) is determined by B=NI, where N= number of turns, I = current. N will not change as the coil heats up. However, the resistance of the coil will go up with temperature. I=V/R where V= Volts, R = resistance of the coil. Volts will not change, so as R goes up, I, the current, goes down. Then B goes down and the flippers lose strength.

    Don C.

    #26 5 years ago
    Quoted from Don_C:

    Magnetic flux density (B) is determined by B=NI, where N= number of turns, I = current. N will not change as the coil heats up. However, the resistance of the coil will go up with temperature. I=V/R where V= Volts, R = resistance of the coil. Volts will not change, so as R goes up, I, the current, goes down. Then B goes down and the flippers lose strength.
    Don C.

    Going from room temp (around 22C) to boiling water (100C) would only increase the resistance by about 1 ohm on a 5020, I didn't realize it would have that much effect on the power. TIL...

    #27 5 years ago

    Seems like a single DC blower might be enough to blow across both coils. Should be quiet enough depending which one is used.

    14
    #28 5 years ago

    One ohm sounds insignificant, but let’s see...

    I don’t have the exact resistance of the 090-5025-00 coil (which is 24-1570, or gauge 24 wire 1570 turns). But flipper coils are generally about 3 to 4 Ohms.

    If the coil resistance is 3.6 ohms at 20 degrees C, what is its resistance at t2= 80 degrees? Temperature coefficient of copper is .00393 per degree C.

    R2 = R [1 + a(t2 - t1)]
    R2 = 3.60 [1 + 0.00393(80 - 20)]
    R2 = 3.6 X 1.236 = 4.45 ohms, or a .85 Ohm increase in resistance.

    So, about a 1 Ohm increase.

    But .85 ohm added on to 3.6 Ohms is about 24% more resistance, or 24% less current, or 24% less magnetic flux available to create the tractive force that moves the coil core.

    If a 24% loss of flux sounds bad, it gets a bit worse! B is not the force of the magnetic field, just the flux. For the force we need another equation. In the formula for the force, the B term is a squared term. So any loss in flux is a much bigger loss in force.

    Stolen from Wikipedia:

    Force between two nearby magnetized surfaces of area A
    The mechanical force (F) between two nearby magnetized surfaces can be calculated with the following equation. The equation is valid only for cases in which the effect of fringing is negligible and the volume of the air gap is much smaller than that of the magnetized material:

    F = B^2 A/2 μ0 (B squared times the Area divided by 2 times mu zero)

    where:
    A is the area of each surface
    μ0 is the permeability of space (very close to that of air)
    B is the flux density

    Area and mu zero stay the same hot or cold. But B has dropped 24%. What is the effect of the 24% reduction in flux on the Force?
    Let’s use some round numbers to illustrate. Let’s say you have a cold coil current of 10 amps x 1000 turns, or B = 10,000 Ampere-turns. So, B squared is 100,000,000.

    Hot coil current is 10 Amps less 24% or about 7.6 Amps. B will be 7.6 Amps times 1000 turns = 7,600 Ampere turns. B squared is 57,760,000.

    Going from cold to hot is going from 100,000,000 A-t to 57,760,000 A-t or 42% less force, or only 58% of your cold flipper strength.
    So a 60 degree C temperature rise, creating a .85 Ohm change in resistance can create a 42% reduction in force on the coil core. This is the very large drop off that people notice.

    I just wanted people to know that it’s not friction, but the resistance change that lowers the force.

    Don C.

    #29 5 years ago
    Quoted from Don_C:

    I just wanted people to know that it’s not friction, but the resistance change that lowers the force.

    Don, thank you very much for spending the time to type this out and explain it. It's exactly the kind of explanation I was looking for!

    #30 5 years ago

    No problem, I spent many years designing the big electromagnets you see in scrap yards and steel mills. Maybe that explains my 'attraction' to pinball.

    Don C.

    #31 5 years ago

    Yes ty from me too! I was just going to type the same thing out myself but I was eating a sandwich. Btw, I did stay at a Holiday Inn Express last night!

    1 month later
    #33 5 years ago
    Quoted from radium:

    Seems like a single DC blower might be enough to blow across both coils. Should be quiet enough depending which one is used.

    I used a 120mm pc fan ties strapped to the wires pointing at both coils and it did its job well

    4 months later
    #34 4 years ago

    DOES ANYONE HAVE A SIMPLER SOLUTION TO THIS PROBLEM? sorry for the caps. seems like adding a fan is a bandaid

    #35 4 years ago

    Adding a fan is the simplest way to solve the problem.

    #36 4 years ago

    In the meantime I installed 2 PC fans with 12 Volt in my LOTR and it works perfect. The main advantage is that the coils are held at constant warm temperature and thus do not change their behaviour over a long gameplay.

    The installation is not so difficult (I have only minor technical skills !). For fixing the fans I used the alu/metal holding of the playfield when open, so that neither the playfield is damaged nor any cables are in danger. Then connecting with a 12V reserve ...thats it.

    #37 4 years ago

    are these 12 volt pc fans all pretty much the same? i am going to order a couple

    #38 4 years ago

    No, they come in many different varieties, with different noise levels and moving different CFMs of air.

    #39 4 years ago
    Quoted from Zora:

    I think the fans come with 3 pole wires.
    Regards
    Eckhard

    Computer fans come with 2, 3, or 4 wires but you only use two to run the fan. The others are for sensors to detect the speed and allow it to be controlled via software.
    I think a 120 mm case fan would work well.

    #40 4 years ago
    Quoted from YeOldPinPlayer:

    Computer fans come with 2, 3, or 4 wires but you only use two to run the fan. The others are for sensors to detect the speed and allow it to be controlled via software.
    I think a 120 mm case fan would work well.

    perfect. thanks man!

    #41 4 years ago

    My LOTR doesn't heat up...
    Why do coils get warm? If the stroke-time is too long the flippers will heat up faster.

    Try adjusting the EOS (the software actually does more than pulse the stroke when a ball is falling on it)
    And try adjusting the software. I believe there are software revisions which allow for 3 extra adjustments for the flippers. At least mine does. Adjustments like minimum stroke time and stroke-time after EOS has been made. And one extra.

    There might also be an adjustment for coil power. Not sure if this is also present for LOTR.

    Again: my LOTR doesn't have heating problems and all shots can be made easily (including the ring from the left flipper in a long lasting game). So it must be possible without extra cooling.

    #42 4 years ago
    Quoted from Richard_BoK:

    My LOTR doesn't heat up...
    Why do coils get warm? If the stroke-time is too long the flippers will heat up faster.
    Try adjusting the EOS (the software actually does more than pulse the stroke when a ball is falling on it)
    And try adjusting the software. I believe there are software revisions which allow for 3 extra adjustments for the flippers. At least mine does. Adjustments like minimum stroke time and stroke-time after EOS has been made. And one extra.
    There might also be an adjustment for coil power. Not sure if this is also present for LOTR.
    Again: my LOTR doesn't have heating problems and all shots can be made easily (including the ring from the left flipper in a long lasting game). So it must be possible without extra cooling.

    LOTR is famous for coils heating up. The adjustments (I think 53 to 55) influence the EOS behaviour, but this had no effect in my LOTR. The heating up affected the flipper strength a lot. Although I had the strong PBL coils (which I now replaced with less stronger ones), it was hard to reach the ring. Some machines have the issue, others not. I cannot tell you where the difference Comes from. Even more modern Pins seem to have week coils and I installed the fan solution in my second NIB machine. It makes a big difference.

    The coil power adjustment does not change the flipper coil strength, only the other coils, IMO.

    #43 4 years ago
    Quoted from Richard_BoK:

    My LOTR doesn't heat up...
    Why do coils get warm? If the stroke-time is too long the flippers will heat up faster.
    Try adjusting the EOS (the software actually does more than pulse the stroke when a ball is falling on it)
    And try adjusting the software. I believe there are software revisions which allow for 3 extra adjustments for the flippers. At least mine does. Adjustments like minimum stroke time and stroke-time after EOS has been made. And one extra.
    There might also be an adjustment for coil power. Not sure if this is also present for LOTR.
    Again: my LOTR doesn't have heating problems and all shots can be made easily (including the ring from the left flipper in a long lasting game). So it must be possible without extra cooling.

    when I got the game there were no eos switches in it. I rebuilt the flippers and the eos switched from the kit were installed and adjusted properly.

    #44 4 years ago

    ADDED FANS. NO LUCK. SAME ISSUE THOUGH NOW I am thinking it's more intermittent than heat related. I will check for loose connections in the wiring and on the pcb. a few have mentioned faulty transistors. also of not the flippers assy's both had the eos switched removed when I got it. i'm wondering if this has damaged the electronics

    #45 4 years ago
    Quoted from rcbrown316:

    ADDED FANS. NO LUCK. SAME ISSUE THOUGH NOW I am thinking it's more intermittent than heat related. I will check for loose connections in the wiring and on the pcb. a few have mentioned faulty transistors. also of not the flippers assy's both had the eos switched removed when I got it. i'm wondering if this has damaged the electronics

    Maybe you should start a tech thread where you can clearly describe the problem, list the game, etc

    #46 4 years ago
    Quoted from markmon:

    Maybe you should start a tech thread where you can clearly describe the problem, list the game, etc

    thats a good idea now. i wanted to read up on it before asking so I found this thread first. i will take your advice though at this point because I just tried a whole bunch of stuff

    #47 4 years ago

    Can anyone explain what the flaw is in the Stern system that causes this? It can't be the coils (I have run them and full Stern mechs off Capcom board set for **hours** without any heat, and retaining the fabled Capcom "feel" still there). Not having an electronics background, I don't appreciate the difference between how Capcom did it so well and Stern so poorly. Must be an explanation in there though?

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