Mains Power Feed Complete

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Mains Power

This is the last mains power update for the ReactorForge Induction Heater. It will be the last because it’s complete! Here is how the last couple days of that process went.

Mains Power

I started by connecting the jumpers from the custom splice connector to the 60 Amp 240-volt dual pole breaker and ground bus. The photo shows green hooked to the neutral bus. I later moved this as I did not need to tap 120-volt like I thought I would have to since the ATX power supply runs on 240-volt now. (I just forgot, it’s been a while.)

Mains Power

And here is the 240-volt quick disconnect assembly installed and ready. I will print another version of the slide lock. The slides should be solid so the splice connectors are not accessible while the wires are disconnected.

Mains Power

Next, I prepared the 2 AWG mains power feeder lines. These will connect the splice block directly to the input of the ReactorForge.

Mains PowerMains Power

The splice block side has thick metal tabs that are double layered with heat-shrink tubing. These provide a high current, high durability connection to the screw terminal that will stand up to multiple connect/disconnect cycles.

Mains Power

The Induction Heater side has heavy duty lugs that will accept the terminal post. These are also insulated with double layers heat-shrink.

Mains Power

Bringing It All Together

And here you can see the feeder lines connected to the input of terminal posts on the back of the ReactorForge. I also ran a USB extension with a small hub for connecting the Atmel ISP programmer. I put the Bluetooth dongle here as well. It communicates with the mainboard to send/receive commands and system telemetry.

Mains PowerMains Power

I then installed a variac between the mains contactor and the inverter input filter.

Mains Power Variac

When software activates the contactor, 240 volts directly feeds the inverter typically. Since I have a decent amount of testing to do, I severed that connection and installed the variac to allow lower power testing.

Mains Power

I taped up the small areas where 240 volts was accessible in the front to avoid accidental contact or tools shorting things out. Getting my fingers across 240-volt mains power is not something I want to experience twice!

Mains Power VariacMains Power

On To The CODE!

That’s it for cooling and mains power connections. The next step is to get the programming environment set back up. I will turn things up as is and do some testing to make sure everything is still good. Once that is done I will get right to the next big task, I’ve decided to port the entire thing to Arduino. This won’t be too difficult since the code is already in C and I will be glad to get away from AVR Studio, to be honest. I made the choice to move to Arduino due to is massive use and rise in popularity over the last few years. Since this is an open source project I want to use a platform that people are familiar with. Let’s put industrial level induction heaters right up there with open source 3D printer firmware!

Nylon 3D Print of the 240V Quick Disconnect

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3D Print 240V Quick Disconnect

In my last post, I showed a prototype 3D print of the 240V Quick Disconnect. Here are the results of the final 3D print.

Nylon 3D Print

I’ve got the final version of the 240V Quick Disconnect printed in in natural colored Bridge taulman3D industrial high strength nylon. It is insanely strong! The first nylon 3D print failed because I forgot to include a skirt, so the edges curled up slightly, and I didn’t notice until it was complete. It still worked, but it bothered my OCD, so I reprinted another, only took an hour anyway. I ran over that first nylon print with my truck (laying flat), and it didn’t get so much as a scratch on it.

The slide lock completely prevents finger access to the Burndy splice connectors. Still, this is not something you should attempt if you are not familiar with electrical safety and codes. Your best bet is to higher an electrician to add a permanent outlet. This assembly setup is for testing purposes only, and I know what I’m doing. Don’t try this at home.

Safety First

Things you should understand if you do try this at home is the earth ground system in your home electrical wiring. You should also understand how NOT to overload circuits, that’s a significant fire hazard. The NEC can help here understand load maximums on a given wire gauge. Finally, understanding how transformers isolate you from the shocking truth will help you understand how the work coil is electrically separated from your home or shop AC grid.

Remember, Safety should always be first! The voltage and current coming from your wall outlets can kill and should always be respected.

Project ReCap and Photos

The updated CAD 3D print files are on on the Thingiverse Project. This assembly houses 3 Burndy splicers (PN: AMS2BAG2R). It does a few important things, it isolates them from each other, from the breaker box, and it snaps closed to prevent the lugs from sliding out (and attacking passer buys). On the side where the wires enter the assembly from the breaker, it is closed off except for holes just big enough for them, so it’s impossible for the splicers to slide out from that side. There are also ears on the front to keep the entire assembly from sliding all the way in the breaker box.

Power Progress – 240 Volt Quick Disconnect

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240V Quick Disconnect

In the photo below is my power test setup at home. Unfortunately, where my other shop is right now, I am unable to make changes like this. Here I explain what I did to get around that and make power progress!

DIY Induction Heater Power

Now that the ReactorForge is back on the bench it’s time to get it powered up!

This setup isn’t necessarily something that an inspector would like to see.  So don’t think this is my recommendation for a permanent solution. I’m just sharing what I did to make my current setup work. Keep in mind the breaker should always be OFF before connecting or disconnecting wires on the quick disconnect assembly.

To hook up 240 to the ReactorForge in this shop I have to run a temporary line. I don’t want to have to remove the breaker each time I do this, so I made an enclosure that mounts in a breaker slot. The assembly houses 3 Burndy splicers (PN: AMS2BAG2R). It does a few important things, it isolates them from each other, from the breaker box, and it snaps closed to prevent the lugs from sliding out (and attacking passer buys). On the side where the wires enter the assembly from the breaker, it is closed off except for holes just big enough for them, so it’s impossible for the splicers to slide out from that side. There are also ears on the front to keep the entire assembly from sliding all the way in the breaker box.

I printed a quick test in PLA, made a few changes and am ready to 3D print the final version in nylon after Thanksgiving. I’m sharing all the files here in case anyone else finds it useful. Be smart, be safe.

Power progress photos:

New Shop Power Panel

My problem is that I do not want to open up the panel and remove the breaker and wires every time I need to remove the temp line.

Power progress

Fusion 360 power splice quick connect

So I drew a simple small enclosure to house some common splice blocks made by Burndy.

The prototype:

 

The slide lock action:

Technical Drawing:

240V Quick Disconnect Drawing v10.pdf

*Tip: I usualy try to make a technical drawing before I 3D print a part. It’s quick and easy in Fusion 360 and saves me wasted prints and time redrawing later. I always catch a lot more looking at the drawing with multiple views and mesurements than just looking at the drawing in the viewport.

You can view and download the CAD files over at Thingiverse – 204 Volt Quick Disconnect Splice Housing 

Cooling is a GO

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Cooling - connected and flushed

I got the new fittings and hoses hooked up then flushed the water chiller and the induction heater. No leaks, cooling is a go!

Cooling - connected and flushed

Cooling - New metal base for cart

Before putting it back on the cart I replaced the top plastic liner with 16 gauge sheet metal that I cleaned and lightly wiped down with oil. I think I’ll go back and add a lip around 3 sides with the box break to catch any falling sparks and molten beads of metal that try to escape.

Back on the cart!

Cooling setup on cart

And here it is with cooling set up on the new cart.

Cooling setup on cart

Now to move on to power. I am making a quick disconnect near the breaker box. I will need to draw and 3D print a small enclosure for the 3/8″ dual splicers. More on that progress here.

Hooking up cooling water and power

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Hooking up cooling water - parts laid out

Hooking up cooling water, but first, fittings!

Hooking up cooling water - fittings

One trip the hardware store later and I’m ready to hook utilities up to the induction heater. 

Hooking up cooling water - parts laid out

Hooking up cooling water isn’t the only step… Power!

I also ordered a larger variac, a 5000VA 220V model to aid in testing and firmware optimization. I have a small 2000VA 120V variac but running it on such low voltage skewed a lot of the readings. The variac is nice because running full power while testing new features can a bit nerve-racking and wasteful.