rebelrider.mike
Member
- Joined
- May 25, 2017
- Messages
- 554
I finished my first home made power supply, and have continued to play around with transformers, so I thought I'd start a new thread.
My first one turned out really good, and now I'm looking at doing more, including adding some safety features that I don't currently have.
I found a much beefier cable, and even grounded the core.
I'm also looking at building a "current limiter" which is basically a high Wattage light bulb in series, so if I short something, the bulb coming on should be the worst that happens.
Another safety thing I want to make is an "isolation transformer" that is 1:1 ratio. The transformer I have is too small for that much wire, but check out this guy I found at the Habitat Store:
Compared to my first transformer, this guy is huge. Before I plugged it in though, I decided to give it a couple tests on the multimeter first. Everything was going well, until I found that there was continuity between the primary side and the secondary side. So, I started taking it apart to see what's inside.
Inside, I found ordinary cardboard paper stuff wrapped around the coil, I figured I'd need to unwind the secondary coil to see what's going on, and I got out my favoritedismantling tools.
The first two plates were a bugger to get out, and got a little misshapen, but the rest came out no problem. Although the outside appears to be painted, it looks like moisture has infiltrated anyway. Lots of rusty dust and a bit of surface rust. I'll have to think on what kind of rust removal I want to do that won't be too invasive on the plates.
I unwound what I thought would be the secondary coil, and found that it is the only coil. ??? Is this one of those non-isolating transformers? My first transformer had a connection between the primary and secondary coils, and only had three wires total. I guess these must be a thing, since I've found 2 out of 2 now. So this will have to be completely rewound in order to get me the isolation I want.
The good news is the spool and wire are in perfect condition.
Since the core is much bigger, I only need 228 Turns for the 122V primary, and probably the same to get 120-122V on the secondary. I mean, ideally I'd use a 1:1 ratio, but there's always losses.
Although the label says it's good for 1000VA, It seems the core is good for about 500W according to the math I've found online. Honestly, I can't think of any use for 500W, but it's good to know your limits.
I've also noticed that the 16 AWG wire is made of aluminum. I can't seem to find info on aluminum Amp ratings for DC. Copper wire was hard enough. For now, I'll guess that it will conduct as well as the next size smaller for copper. At 18 AWG, that'd be 3.2A. I may just buy all new copper wire. For the amount I'd need, that would get pricey though.
My first one turned out really good, and now I'm looking at doing more, including adding some safety features that I don't currently have.
I found a much beefier cable, and even grounded the core.
I'm also looking at building a "current limiter" which is basically a high Wattage light bulb in series, so if I short something, the bulb coming on should be the worst that happens.
Another safety thing I want to make is an "isolation transformer" that is 1:1 ratio. The transformer I have is too small for that much wire, but check out this guy I found at the Habitat Store:
Compared to my first transformer, this guy is huge. Before I plugged it in though, I decided to give it a couple tests on the multimeter first. Everything was going well, until I found that there was continuity between the primary side and the secondary side. So, I started taking it apart to see what's inside.
Inside, I found ordinary cardboard paper stuff wrapped around the coil, I figured I'd need to unwind the secondary coil to see what's going on, and I got out my favoritedismantling tools.
The first two plates were a bugger to get out, and got a little misshapen, but the rest came out no problem. Although the outside appears to be painted, it looks like moisture has infiltrated anyway. Lots of rusty dust and a bit of surface rust. I'll have to think on what kind of rust removal I want to do that won't be too invasive on the plates.
I unwound what I thought would be the secondary coil, and found that it is the only coil. ??? Is this one of those non-isolating transformers? My first transformer had a connection between the primary and secondary coils, and only had three wires total. I guess these must be a thing, since I've found 2 out of 2 now. So this will have to be completely rewound in order to get me the isolation I want.
The good news is the spool and wire are in perfect condition.
Since the core is much bigger, I only need 228 Turns for the 122V primary, and probably the same to get 120-122V on the secondary. I mean, ideally I'd use a 1:1 ratio, but there's always losses.
Although the label says it's good for 1000VA, It seems the core is good for about 500W according to the math I've found online. Honestly, I can't think of any use for 500W, but it's good to know your limits.
I've also noticed that the 16 AWG wire is made of aluminum. I can't seem to find info on aluminum Amp ratings for DC. Copper wire was hard enough. For now, I'll guess that it will conduct as well as the next size smaller for copper. At 18 AWG, that'd be 3.2A. I may just buy all new copper wire. For the amount I'd need, that would get pricey though.