Magnet wire awg question

[bongmuon]

Ok, obviously this question is for sparky....

I am attempting to rebuild a vtec solenoid for my mom's car. I have the old one apart and know how many windings i need to make it back to what it was again but I have been having trouble finding 30 awg coated magnet wire. I found what I believe is 31 awg wire in sufficient amounts to fit my need but is it going to be able to behave the same or will it be completely wrong? Is there a way to compensate by adding or subtracting windings?

[Sparkie]

The resistance should be about 25% higher using the smaller gauge, which may prevent the solenoid from reaching the current required to achieve the desired flux density.

That being said usually magnetically are built with a heavy margin, so I’d give it a go for sure.

That being said, have you checked sayal
https://secure.sayal.com/STORE2/View...php?SKU=231825

[bongmuon]

That's a lot of that being said being said! lol

Thanks, I will definitely check that store out. I had no idea about that store and they seem to be everywhere.

[Sparkie]

I’m curious, did you rewind the solenoid? Did it work?

My buddy who lives in his caravan just had a transmission solenoid die on him so I’m very interested

[bongmuon]

I did rewind the solenoid and it looked beautiful..... the third try.

I plastic welded the housing back on it and I must have put too much heat into the plastic and melted some of the coating off so the resistance went down to 7 ohm. It also could have been my crap soldering skills that heated up the wire too as I had to reconnect the connector to the rest of the housing and I have never had to solder that big of a difference of 2 mm thick metal to 30 awg wire. I still tried to install it but the plastic I used wasn't strong enough as when I installed it it snapped off and broke the wire.

If the solenoid doesn't have a plastic housing you should be able to do it. Just be patient with the hand winding it takes hours to do it perfectly and you need some sort of method to tension the wire as you wind it. I also used my tester contact to push the wire into perfect alignment while winding (carefully as to not remove the coating).

I spent a ridiculous amount of time doing it 3 times... I'm talking 3 days labour lol. It was for my mom's car and right now I have all the time in the world as I'm not working and cost is a big deal for her due to budget restraints.

[bongmuon]

p.s. I already have gone to Sayal twice now and am in love with the store. You are making me spend a lot of money but I now am learning a lot more about electronics, I'm even making a system that uses an arduino and flame sensor to turn my jerry rigged vent fan on.

Don't worry it is actually more safe than it sounds.

[Sparkie]

Yeah I love sayal but it’s dangerous and I could definitely spend all my money there. Wait till you start making your own circuit boards with a laser printer and some ferric chloride.

I assume that despite using a flame sensor, there’s no actual fire involved?

[bongmuon]

Its an optical one, osepp flame sensor. It is going to monitor the flame through the pilot light viewing window. I am using a normally closed relay to turn the fan off when it is only the pilot light going. If anything fails the fan will be on.

[Sparkie]

Sounds interesting.

One thing I’d like to point out as this gets further off topic: most silicon switches fail closed; so the BJT or FET you’re using to turn that relay on will act as a short circuit if it blows. Make sure you have a protection diode across your relay coil - the inductive kick from turning that relay off is the thing most likely to kill your transistor.

[bongmuon]

https://maker.pro/arduino/projects/d...ith-an-arduino

That's the circuit I'm using as a base just turning the led circuit into an isolated ac line.

Using G2R-14 NC relay.

[Sparkie]

Edit diode is fine in that schematic...

Aside from the power being drawn on the bottom and the ground being on top like some kind of circus sideshow it looks allright.

[bongmuon]

haha yeah the ground on top was bothering me too.. guess BMW wiring diagrams got that stuck in my head.