Air Core Gauge Motor Teardown (Older type)
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- Опубліковано 21 лип 2018
- Teardown of an older Air core gauge motor. These are out of an older GM truck instrument cluster but are used in other brands of vehicle. I show how I remove the resistor and then do a destructive teardown of the coil.
I was told the "T" at the beginning means temperature gauge. That sort of thing is super helpful to know.
en.wikipedia.org/wiki/Air_cor...
Thanks for watching
Thank you for making this video! It helped greatly with my project.
Thank you for the video. I hope it will help many.
I appreciate that you took my request into consideration.
Shows that you truly value your viewers.
No problem! I appreciate the video suggestion. Hopefully other people will benefit. I had no idea a seemingly simple air core motor was so interesting.
Thanks to both of you!!
Great break down
Nice video. Thank you
Btw the first letter is a "T"
Its for the temperature gauge.
Hi.. My problem on my air core motor is tight turn.. I scavage neodium magnet from hard disk drive to chek if its turning,yesnit does but super slow like its so tight
Good video
watched just for the info. Not that it will be used but info is power.
I'm thinking that resistor is on there to calibrate the device. It is difficult to wind coils so they are identical. So the resistor is custom trimmed for that particular meter. If your resistor gets cracked or otherwise damaged, the resistor from another air core gauge will do better than nothing, but it won't be properly calibrated.
I imagine they are intentionally made so that the coil with the resistor has a turn or two more, so it is guaranteed to be a little stronger than the other coil. Then that flat film resistor is added and laser trimmed.
You could replace it with a resistor and a ten turn potentiometer. Simple to calibrate - full current through one coil, that's 0 degrees. Current off, full current through the other coil, that is 90 degrees.
Now connect the coils in parallel so they get exactly the same voltage. Trim the resistor so the needle is precisely at 45 degrees.
Interesting, very technical. pro electricians are like magicians. Wow.
@@chrisgooi Electronic engineers and electronic technicians. Electricians wire houses.
Using 12v right?
When they start getting erratic is there a typical reason why like a short between the coils or are there a couple different things that can cause it? Assuming everything else in the circuit from the sensor/sender to the gauge tests good.
I'm not 100% sure but what I have learned so far is that its partly to do with physical resistance of the mechanism. Over time the wear surfaces get smoother and they then get wonky. I have not gotten a true response yet though from someone definitively so take what I say with a grain of salt.
Supposedly the rotor chamber on these were originally filled with a thick silicone oil that dampened their movement when the fuel sloshed around. Hey I read it on the internet so It must be true! Anyway if true, I wondered if an alternative would be to make some kind of external resistance. Specifically was thinking maybe a thin rubber or plastic piece I put a hole in for the shaft to go in, then have that piece mount between the motor and gauge face plate and held in place. Either by holes in the "friction" piece that the mount screws go through or make it where it would fit between the plastic mounts to keep it from rotating. Does that sound like it would have any chance of working?
Everyone knows you cant tell lies on the internet! It must be true. I heard it was Henry Ford's blood that they used.
As far as your idea, honestly maybe. That was what I kept kind of coming around to. That there needed so be some sort of "soft resistance". Granted they are kind of cheap(the newer models that are flat and white) but these might benefit from something like that.
@@FixitFrank So you think the oil filling is doubtful? Seems like if it did leak out you see it all over. The one in my 97 chevy truck moves around a lot when the truck is moving as if it following along with the level float moving up and down a lot. I actually it maybe it was some kind of electronic dampening device that might need replacing. Once you stop it settles down and seem to give good readings to the actual level. I don't personally mid it, but it really concerns my wife especially when it's got like a 1/4 tank and keeps dropping down to E. Googling I did find some adjustable electronic devices devices that supposedly can be used to any sending unit and any gauge for folks retro fitting gauges in an old or car they are modifying that supposedly have some kind of anti-slosh built into them. One example I found, nothing I get money from.
www.tanksinc.com/index.cfm/page/ptype=product/product_id=748/mode=prod/prd748.htm?gclid=CjwKCAiAxp-ABhALEiwAXm6Iybjl3ljon7S3v5e7CLclZQhAwTGyWV-P7GEWpaxKwTNZkUuB_WATdxoCZG0QAvD_BwE
Looks fairly straight forward to set up
www.tanksinc.com/pdf/MeterMatchInstructionManualTanksInc.pdf
This one looks like you can set it up for various manufacturers and years before you start it up and you're done.
static.speedwaymotors.com/pdf/910-12910_2019.pdf
I'm guessing I'd have to see if there is just one wire output coming from the sender as I'm not sure how I'd wire into that gauge panel otherwise based on the wiring diagrams they show. GM supposedly had a TSB on late 1997 a fuel level damper kit 12167652 but they no longer make it.
Hello! Great video. I have a question, you seem to know a lot about these stepper motors. I'm repairing a 2002 mustang gauge cluster, and it has air core motors on it, however they don't have any markings on them, and I can't find any information online to purchase them or even what they're called. Maybe you might know a source of information, or possibly know what kind they are? It will be much appreciated! Thank you!
Hi Jim, There should be some small lettering somewhere. Are they similar to this type in this video?
Yes it's very similar to the one in the video. The only marking I can find on it is a tiny number "13" on the plastic. I could send you a picture to your email if you like. Thank you for the reply!
So what's there to go bad on it? No bearing. So either the coil wiring could fail or the resistor could fail. I don't see what else could go wrong.
You'd think so, but the coils and resistor are still good. I think its more the small wear surfaces where the axles rub against. I 'think' there is some friction used to keep the meters moving evenly. Another possible cause is the magnet in the rotor getting weak. I'd like to spend more time learning why these fail but that time thing is weirdly limiting...
So I need to convert these type motors from clockwise direction to counter clockwise. Any ideas or help appreciated.
you can try wiring them in reverse. youd have to cut the traces on the pcb but if you wire the top to the bottom and lef to the right, it should run backward.
My understanding is there is a filament or silicone in them that goes bad over time. Do you know where that filament should be, how to tell if it’s bad, and how to replace it?
Do you mean in the axis? My only guess is the wearing surface becomes worn out and no longer has the same friction. That is purely a guess though. I may have to revisit this. I still have the motors in a drawer. I can't answer your question on repairing them though. I tend to replace them since I do not really understand the failure mode.
I’m not sure if they’re repairable, I’ve just noticed that as they age, they begin to turn easier which causes them to bounce. I was hoping there was a way to restore that friction to eliminate the bouncing if that makes sense.
In the mean time, do you sell replacement motors or care to share a good source to get some new ones?
I get them on eBay or Amazon most of the time. eBay if I am not in a rush. I usually keep a set of GM and Dodge around as I get requests for them the most. I need to make a driver circuit to run one while out of the cluster to try and see what the failure mode is. I'll add that to my videos to make list.
FixitFrank that would be really cool! Thanks for the info!
I know this comment is old but yes, you can repair them by adding oil to the air core motor. The oil acts as a damping fluid that will keep it from bouncing. All you have to do it add oil and the needle will work like new.
Do you know how to repair a defective one by adding a resistor to it
How so? I don't work with these often. If you have any insight, I would be interested to understand.
I need to repair my fuel gauge motor
The resistor is there to balance the coils. With a cracked or burnt resistor, it will show accurately at 0 degrees and 90 degrees, but will be off between those points. The resistor seems to be laser trimmed for each air core gauge. I posted in another comment about it.
Frank, still answering questions about air core gauge motors? Have a question on diagnosing, repair and suppliers. (From 1995 garden tractor instrument panel)
I am not an expert on these. But I am happy to offer any information I can! Feel free to ask.
Hello! I am trying to find info on an air core motor for a John Deere tractor instrument cluster that is really a strange design. The ones I have were rusted and don't move free. I got one to move and another, barely. Your explanation of their principle is great! And has helped me understand how simple they are, tempting me to try and fix them. I have pictures if you have the time to take a look and give any advice you could give, They can not be found anywhere. Not sure how to get them to you.
frank can you message me the part numbers or playe where you boughy yhe needle and silicone
It was on ebay years ago. Unfortunately the seller does not seem to list anymore. Im sorry.
How do you refill the dampening fluid?
Have you found any good videos/articles on doing this?
@@timmyv1979 nope
Here's one where "Jeff" shows how to restore the gauge dampening fluid. It starts at about the 12-minute mark, but I like watching the entire vid. Some good stuff here from GM IPC repair guru...
ua-cam.com/video/TLtDw_Sjh1o/v-deo.html
Would this sort of stepper motor be similar to one from 1980? 😅
It probably is pretty close. These were early 90s/late 80s so I suspect the earlier 80s models were very similar.
Where can I buy the air core motor?
I find them on eBay or Amazon believe it or not. They have whole kits with solder and everything.
do you have a know good F for 96 tahoe I believe it is yellow
I'm sorry I don't. I have sourced them from EBay in the past but I know the older ones are harder to find. I'll ask around though. I am not a mechanic but I know a few and they tend to throw me the electronic work when its above their skill level. I have repaired more ECM/BCMs and other weird automotive boxes than I can remember. I'll see if they have any 96 GM truck clusters around with good fuel gauge motors. If you want to drop me a line in my email( on the about page), I will let you know if I get my hands on any.
can I pm you
frank@fixfrank.com
You could have left the pins in when removing the can, but I guess that is moot, since this is a teardown...
t is for Tac p is for pressure
Fantastic! This is how we all learn! Thanks so much
@@FixitFrank do you have a know good f for a 96 tahoe
T isn't tach, T is temp, Tach and the Speedometer both use S.