Induction brass annealer redux

[GrocMax]

Not wrong good catch, my mistake, on the rotary switch pin 1 should be to the sub board 0v and not connect to the PS pin 11, so I see why there might be some confusion.

When the switch is in position 1 the 5v ref voltage has to pass thru all the resistors to the 0v, so the voltage output for the center tap is lowered with increasing resistance. Pin 7 is 0 resistance so the full 5v is passed on to the center tap.

Having a near 2v switch position (approx. 6.5A) is useful for smaller thinner cases in my opinion.

You could probably get away with fewer steps, 7 steps is more than enough in the real world, 4 or 5 would cover everything from 22 hornet to 50 BMG, just set up the resistors on the switch to cover the entire range from 2.1v to 5.0v in even steps.

Attached is a spreadsheet to help calculate PS output for each resistor step and the resistor value needed. These are approximate values as the response is not perfectly linear but in reality they are pretty close, within +/- .1 A .

Maybe this was the wrong word ;-)

At pg 19/#373 (att 1.jpg) there is the schematic with the hint to connect only to 7 of the power supply (without 11) - that's fine with me.

At pg 18/#345 (att 2.jpg) there is the schematic of the sub board.
Switch position "1" is connected via the black line to 0V of the 5V-LVR.

If I switch to position "1" 0V is connected to 7 (power supply - current limit control).
In this case the voltage is less than 2V and I'm not sure if this is right and what happen.

In your first idea pg15/#300 there is a resistor between the pot and 0V that is preventing that the voltage goes below 2V - that's fine with me, too.

Maybe I'm wrong and I haven't see this resistor in your schematic.

 

[dskogman]

Here is some more part info for those starting out. I ordered a power supply from TOTIWO on eBay based on Targetshooters post. It was shipped DHL and was here in 7 days. Prices are:
48v 600 watt = $65
48v 720 watt = $70
36v 1000 watt = $90
The 1000watt/50amp ZVS induction heating module was $37.20 and took 10 days. Other smaller parts took longer.
Not amazon prime speed but not bad and cheaper.

 

[dskogman]

Connected up the parts to test it and immediately got sparks and pop when I closed the relay. Took off the coil and tried once more and the same thing. Checked all the wiring before and after and it looks correct. Sounds like I got a bad board? Didn't see any obvious burns but I shut it down very quickly. Are they fixable or just try again?
I am using an SSR (single contact).

 

[Gina1]

Connected up the parts to test it and immediately got sparks and pop when I closed the relay. Took off the coil and tried once more and the same thing. Checked all the wiring before and after and it looks correct. Sounds like I got a bad board? Didn't see any obvious burns but I shut it down very quickly. Are they fixable or just try again?
I am using an SSR (single contact).

Hard to figure out what's going on, with my not being there. Lets try just this (kiss) keep it simple With the coil hooked up to the inductor PCB, coolant flowing through the coil. Connect the 48 volt PS to the power input of the inductor PCB (be sure to have the 48VPS turned on and powered up.)
As far as the original parts spec, the relay called our is a DOUBLE pole single throw relay. Some folks have been having problems trying to use just a single pole relay.

Keeping it simple, once the inductor comes up, you can check it out by holding a case in a pair of pliers and see if the case gets hot.

 

[GrocMax]

Parts list and wiring diagram would help with diagnosis.

What SSR, how many wires on it (3 or 4) ? Wiring these can be non-intuitive, easy to wire incorrectly. To clarify, unlike a points contact relay, a DC SSR has transistors and diodes, and polarity matters.

For brief testing, use the coil supplied with the induction board don't worry about cooling it.

 

[Mike17]

I'm a little bit behind schedule.
So I had no chance to test it up to now.
After reading this I've connected the PS, SSR and induction board to see if I was wrong with the SSR.
I used the coil supplied with board.

It works without any problem. I also couldn't see any shining in the dark.
Where do you get the sparks?

I assume you know what you are doing. But sometimes four eyes see more ;-)
I use the FOTEK SSR-40 DD. (http://www.ebay.de/itm/2X-Einphasen...-40A-DC3-32V-DC5-60V-Weiss-S-H3-/252699792245)
This SSR has 2 connectors at each side.
I had to think twice when connecting it to the circuit of the induction board.
The first side is labelled with "Input". This is the side where you connect the timer.
The second side has a symbol similar to a capacitor and is labelled 5-60VDC.
Be shure it is a DC-DC SSR. Most SSRs in ebay are DC-AC SSRs (eg labelled SSR-40 DA).

I've connected the SSR in the positive path.
+ (Pin2) of the SSR to + PS
- (Pin1) of the SSR to + of the induction board.

Mike

 

[Mike17]

When connecting the parts I also connected the V/A-Meter to see what happens.

The meter displays 48.1V and 16A with just the induction board without case.
The real current is only 6A (checked with 2 different multimeters).
The displayed value can be adjusted between approx. 16A an 60A

I use this VA-meter: http://www.ebay.de/itm/DC-0-100V-50...meter-Spannung-Strom-Panel-EP98-/111827788891
A manual is not available. Even the charts in ebay do not all fit to the deliverred VA-meter.
I've blue, green, yellow, red, black cables and connected like the last picture on ebay.
The shunt is labelled with 50A.

I hope the parts fit together ;-)

Do you know about a similar problem before?
To those of you who own the same one: Is there possibly a solder bridge to switch between 50/100A?

Mike

 

[GrocMax]

I can't find the mV per Amp scaling information and adjustment instructions for that unit. This is one of the major problems with Chinesium Ebaysium Amazonium products, lack of technical support.

Maybe try the other shunt and see if it is scaled correctly?

There must be some way of switching the mV per amp scale to use the 2 different shunts. The adjustment pots should be a minor adjustment for calibration.

Also if it has an internal shunt this circuit may need to be open to use an external shunt.

Looks like most of these use 75mV voltage drop to indicate full scale current of 10A, 50A, or 100A.

 

[Mike17]

The shunt I own is labelled with 50A 75mV.
The other in the picture of ebay is labelled with 100A 75mV

I had to choose between the 50A and 100A shunt. So unfortunately I can not test the other one.

I will temporarily create a mapping table.
If I find no solution and I'm annoyed enough I will order a new one ...

Mike

 

[dskogman]

Test setup...


Removed SSR and volt meter and did a direct connect. You can see in the video a cap by the power connection sparks immediately and trips the power supply. Looks easy to replace but no markings on it. Also don't know what caused it in the first place. Don't want to blow the power supply also

Video...

 

[Gina1]

I'm not sure what is going on with your set up. Maybe I'm not getting a good picture of your induction coil, but it looks like only 3 turn, should be 8. Also make sure none of your turns are shorted.
I think I see a fifth wire going to your inductor PCB, guess that's for the fan. Sparks like that usually not good.. May have a cold solder joint on the PCB, check it out.
Gina

 

[dskogman]

The coil has 8 turns. There is a capacitor marked 104 1KV that is split that is making the sparks. I suppose I could replace it but something else is probably causing it to blow. I sent a refund request so I'll see how far I get before hacking it up.

 

[Gina1]

Refund request.... good option

 

[golong]

I have been poking around this thread in lurker form for a while and decided it was time to register - I am a bit challenged when it comes to matching the correct electronic parts in the full-on creative mode.

My intent is to build the annealer using an RSP-1000-48. I will also be using the SainSmart 1000W 12v-48v board. Despite my going through the entire thread a couple of times, along with some text searching, I am "currently" struggling to understand the following:

• If I want to stay with a DC relay, which relay should I go with?
• Given the PS can be dialed back to 43V on-board do I need a potentiometer or no? If I need one-- or I guess even if I just want to be able to adjust remotely --which one do I want/need?
• With this PS, is the voltage adjusting the amps, or is something else doing that?

 

[GrocMax]

I have been poking around this thread in lurker form for a while and decided it was time to register - I am a bit challenged when it comes to matching the correct electronic parts in the full-on creative mode.

My intent is to build the annealer using an RSP-1000-48. I will also be using the SainSmart 1000W 12v-48v board. Despite my going through the entire thread a couple of times, along with some text searching, I am "currently" struggling to understand the following:

• If I want to stay with a DC relay, which relay should I go with?
• Given the PS can be dialed back to 43V on-board do I need a potentiometer or no? If I need one-- or I guess even if I just want to be able to adjust remotely --which one do I want/need?
• With this PS, is the voltage adjusting the amps, or is something else doing that?

RSP-1000-48 does not have the current limiting control feature, just the voltage limiting control. 750w is more than enough in my opinion even for 50 BMG. You do not need an external control to set maximum voltage on either the 750w or 1000w, the adj. pot on the PS sets max voltage, the remote control won't override it.

If your control system is 12v DC, there s a part # for a Tyco 12v automotive style relay back on pg 16-17 or so, this one has survived with zero issues for 15000+ cycles for me. If your control system is 110v or 220v AC a small motor contactor style relay makes more sense as contactors can be purchased with a wide variety of different AC or DC operating coil voltage/ amp ratings. The contacts don't care if they are switching AC or DC for the most part, but the coils need to be matched to your system voltage and type.

The RSP-750-48 has both remote voltage limit control and remote current limit control, the voltage control was useless, trying both at once was useless (they fight each other) using the current limit control I feel is very handy (but not totally necessary).

Using current control, when the PS is under load the current limit control sets max current, then voltage automatically lowers to maintain the current to the setpoint. This works well, initial voltage is high, the induction board fires off the tank circuit properly, then can go down to 5v if current limit is set low. With no current control the workpiece (brass size, brand, placement in coil) and coil itself determines how much current the system draws.

Using either current or voltage control requires extra circuitry, a regulated 5v supply is needed to provide the 5v. This feature can always be added later its not necessary to go fancy right off the bat, especially if you are not comfortable with electronics projects.

 

[golong]

Thanks. I have no issues building the circuitry, it is picking the right parts when it is not part of a system that gets me. Replacing capacitors in TV's, rewiring vehicles, RC stuff, houses, etc. are all fine. I just need to know what parts.

When matching the coil, part of where I am getting confused it is the amp ratings since some went with AC and others with DC. I have not found anything that converts them straight across yet, and the DC relays I am finding that match the PS look like expensive mistakes (I will make mistakes). Is there some formula I can use to convert AC amps to DC? But then again, if I use the RSP-750-48 instead of the 1k, maybe it will be easier to find a reasonably priced DC relay.

The PS will only be used to power the induction board, and maybe the fans and water pump. The current plan is to use on of the 12v DC units that I have laying around to keep the induction isolated. The control system will be from a raspberry pi. I plan on using the RP for controling how long it should fire for different brass, a beam sensor to start the annealing timer, log the event for that batch, etc. I am also likely not going to use the trap door. If things go as planned, I will have a machine shop make what resembles a very (extremely?) lightweight single stage press that takes a standard shell holder. I will then manually lift the ram to bring the case into the coil. If I can find the right gear setup (I do not want to use belts), I will see if I can get the RP to move the press assembly up and down. This should allow the RP program to put each case at a consistent height in the coil, based on the cartridge program. The 3D printing lead screw motors look promising for this, but it may take some time to figure out so I will just leave room for it in the initial build.

I am really interested in keeping the current down to where the coil is not doing big swings. I will be annealing small and large brass, and I like the idea of consistency (which is why I want induction instead of flame). I went back and looked a pages 15-16. I was not putting together the 5v was going back to the PS to control this. I have not messed around with the RP rotary encoders -- I wonder if I can get the stepping to match the pot positions and adjust the current based on the selected program. Maybe something to try. Then I may have current, time, and height for each cartridge controlled by the RP program.

 

[dskogman]

If your going to use a Raspberry PI you might just want to use an SSR controlled by the PI

 

[golong]

If your going to use a Raspberry PI you might just want to use an SSR controlled by the PI

That is the plan, rather than a TRS. Mapping out parts today (ordering things now), I think, it may be better to use an Arduino. The step motor control of the RP seems, well, less snappy. The thing I do not about the arduino step motor control is, at least thus far, it seems it cannot be stopped by an action, like tripping a beam. It can only count rotations (partial/full). Not a deal breaker, just likely need to take it back to zero every time it goes to change positions.

Found a fair amount of people that are using raspberry pi controllers to control the arduino in robotic builds, so that is an option as well. Just not sure what is involved yet. Another option may be to have the arduino log to a web server, which would solve some of the things I wanted the RP for. Unfortunately this means I should figure out for sure if I will be doing the step motor, and how it will work, now rather than later. It would not be fun to build the electronics to the RP only to swap everything over later. Not horrible, but unless I put all the pc stuff on its own shelf (maybe should anyway?) it could suck to wire to a different board.

 

[GrocMax]

I was referring to the operating coil on the relay or contactor, which needs to be matched to what your control system uses. Coils will be different for 12v DC, 24v DC, 220v AC, 110v AC. The contact amp and voltage rating should be listed in the relay's fine print.

Downside of an SSR of a large enough capacity to handle the full 50A of the induction board is heat, and by nature a transistor has a significant voltage drop across it (why it gets hot).

Arduino or RP should have a 5v supply on it already, no need to add one. Could probably add a DAC chip to output your PS control voltage from the arduino instead of an analog resistor network switch.

 

[Gina1]

WOW... things have changed from the basic "GinaErick"