Induction brass annealer redux

[kit-808]

A big thank you Gina for all your effort in making this task easier for the rest of us, getting parts together for my take on your hard work, hope you like what i do with it.
Will keep you posted

 

[Gina1]

Thank you, Kit. If you have any questions, always feel free to PM me. AND yes I would like to see how your build turns out.
Good luck
Gina

 

[Terry Altom]

Gina,

Is there any problem with too much lacquer on the coil?

Getting close......

 

[Gina1]

No.. As a mater of fact, the extra lacquer may help hold the coil turns in place.
Gina

 

[Terry Altom]

Quick tip. if you dip about two inches of the large vinyl hose into hot water for a minute, it's much easier to insert the smaller hose.

 

[bertn]

Hi, my first post on this website.
Thanks Gina and Erick for sharing all this.

I'm going to build one as well!

I'm from Canada so have to do some extra work in sourcing the parts here.
Just ordered the timer, v/c meter and zvs induction board from ebay
and already picked up the 1/8 and 1/4 tubing and some other bits and pieces locally.

My electronics knowledge is still pretty limited so I have a few questions that I hope you can help me with.

Why 120vac fans? You could use 12vdc and run them off the 12v transformer.
they are only $ 3.56 a piece so about $20 in savings. (They can also easily be salvaged from old pc's).
https://www.amazon.com/dp/B01M3O8UQT/?tag=accuratescom-20

The biggest cost on your shopping list is the power supply so I was wondering if a 12v 600w ATX power supply (<$30.00) would work as well?
https://www.amazon.com/dp/B0083Y978G/?tag=accuratescom-20
It's lower voltage but same watts, so more amps. This would cut the cost of the power supply in half.
With 12v you can also use cheap 12v high current automotive relays (2 x $ 1.76) instead of a more expensive 120v contactor.
http://www.ebay.com/itm/1Pc-Heavy-D...113822?hash=item3f6debdd5e:g:DJ0AAOSwx2dYEHzq

When using the 12v relay would a varistor still be needed?

Hope you can answer my questions.
Thanks a lot,

Bert

 

[Terry Altom]

Couldn't resist an initial test tonight. No pump, fans, or solenoid yet but the volt meter showed 48.0v and the timer worked. Hopefully I'll be able to get it running this weekend.

 

[Gina1]

Good to hear it Tal.
The instruction sheet that comes with the timer is a bit confusing. But once you power it up and play with it it becomes understandable.
good luck and keep going
Gina

 

[Gina1]

Hi Bert..
Some really good questions there.

First, 12 volt DC fans are a good suggestion, and a number of other builders have used them. Anyone who has taken apart and old PC usualy winds up with a few 12 V DC fans. I went with 110 V fans, in that my first build (mod1) has a low current power 12 volt supply and could not handle the additional load of the 12 V fans. So I went with 110. The parts list was just a carry over from that. !2 volt fans are good if your 12 volt DC power supply could handle that.

I do not know how a 12 volt 600 watt power supply would work with the ZVS induction board. There is not much information on the board. But I've heard that the voltage range is from 12V to 50V.
You could be the first to try it and get back to this thread. As a matter of fact I've had to set my 48V PS back a little to 43.0 volts as I was pulling too much current.

As I've said before, this is the members build. Shuck,s I've seen some interesting and money saving ideas come out of it. One really good one was using an old computer/cell phone charger (12 volt) for the 12 volt power supply in the annealer. (as long as it has enough current capacity)

Again, going with a 12V relay is a good cost saving idea..But one fellow has run into problems with that, and has burned up 2 relays. The varistor is for AC relays. A DC takes another approach.
As you know the timer relay (A) controls how long the inductor relay stays closed, providing power to the ZVS board. When relay (A) opens removing power to the relay coil, the collapsing magnetic field of the power relay produces a counter magnetic field AND a reverse polarity voltage across the relay coil. In the 110V relay the varistor shorts out this this high voltage field.
With a 12 volt DC relay, the volt may not get high enough for the varistor to conduct (or short it out)
So what happens with a 12 v DC relay, the voltage produced in the coil has no where to go, so it may oscillate, or jump back to the contacts of relay A of the timer, shorting its contact life.
The following drawing is how wire the power relay up. You can use the same 1N4007 diode that you use for the trap door solenoid.
Hope this helps AND good luck on your build. Any question feel free to PM me. Also when you finish I would love to see "your" creation
Gina

 

[Frog]

Of note is after your first order, you get free shipping at Jameco for over $25 orders within 30 days.

The email I got from Jameco said it was good till 1/31/2017

 

[Gina1]

Bert....

About that DC relay (auto relay) The price is good and it will work. BUT you have to add another capacitor to take care of arcing at the contacts. If your older than dirt think points and capacitor type of ignition systems. The capacitor was added to prevent arcing at the points and premature ware of the contacts.

Want to thank Jose in Spain for finding this and bring it to my attention. The capacitor Jose used was 1000uf @63 volts and is onnected between the relay contact and common.

I don't think this is a problem if you use the A/C relay as that is a DPST relay (contactor) and both the + and - (common) power leads and connected and disconnected at the same time.

Gina

 

[Frog]

What about using a solid state relay

 

[bertn]

Hi Bert..

First, 12 volt DC ..................

I do not know how a 12 volt 600 watt power supply would work with the ZVS induction board. There is not much information on the board. But I've heard that the voltage range is from 12V to 50V.
You could be the first to try it and get back to this thread. As a matter of fact I've had to set my 48V PS back a little to 43.0 volts as I was pulling too much current.

As I've said before, this is the members build. Shuck,s I've seen some interesting and money saving ideas come out of it. One really good one was using an old computer/cell phone charger (12 volt) for the 12 volt power supply in the annealer. (as long as it has enough current capacity)

Again, going with a 12V relay is a good cost saving idea..But one fellow has run into problems with that, and has burned up 2 relays. The varistor is for AC relays. A DC takes another approach.
As you know the timer relay (A) controls how long the inductor relay stays closed, providing power to the ZVS board. When relay (A) opens removing power to the relay coil, the collapsing magnetic field of the power relay produces a counter magnetic field AND a reverse polarity voltage across the relay coil. In the 110V relay the varistor shorts out this this high voltage field.
With a 12 volt DC relay, the volt may not get high enough for the varistor to conduct (or short it out)
So what happens with a 12 v DC relay, the voltage produced in the coil has no where to go, so it may oscillate, or jump back to the contacts of relay A of the timer, shorting its contact life.
The following drawing is how wire the power relay up. You can use the same 1N4007 diode that you use for the trap door solenoid.
Hope this helps AND good luck on your build. Any question feel free to PM me. Also when you finish I would love to see "your" creation
Gina

View attachment 992753

Bert....

About that DC relay (auto relay) The price is good and it will work. BUT you have to add another capacitor to take care of arcing at the contacts. If your older than dirt think points and capacitor type of ignition systems. The capacitor was added to prevent arcing at the points and premature ware of the contacts.

What to thank Jose in Spain for finding this and bring it to my attention. The capacitor Jose used was 1000uf @63 volts and is onnected between the relay contact and common.

I don't think this is a problem if you use the A/C relay as that is a DPST relay (contactor) and both the + and - (common) power leads and connected and disconnected at the same time.

Gina

Thanks a lot for your reply.
I ordered two of those relays i mentioned in my first post last night never realizing that it could be a problem that they are single pole instead of one double pole.

Thanks also for the capacitor info.
Im pretty technically inclined but electronics is the weak part...

How likely is it that the two single pole relays will not switch exactly at the same time?
Alternatively would it be possible to switch only one wire from transformer to inverter board to complete the circuit?

Thx
bert

 

[Jose_Luis_G]

What to thank Jose in Spain for finding this and bring it to my attention. The capacitor Jose used was 1000uf @63 volts and is connected between the relay contact and common.

Just to make sure everyone knows what we're talking about, must say that it has to be an electrolytic capacitor, so don't forget to place the right polarity in the right place.

 

[itchyTF]

How likely is it that the two single pole relays will not switch exactly at the same time?

VERY likely.

 

[bertn]

[Dint think thatog, post: 36860070, member: 1300158"]What about using a solid state relay[/QUOTE]
Dontthink

Just to make sure everyone knows what we're talking about, must say that it has to be an electrolytic capacitor, so don't forget to place the right polarity in the right place.View attachment 992936

Thanks a lot Jose!
Looks like you know what you are talking about

I guess this schematics answered my last question to switch only one wire (with single pole relay) to the board instead of with a DPST relay.

 

[normmatzen]

Be very careful with adding a capacitor across the relay contacts. First, the capacitor across the points of an old auto ignition is NOT to stop arching, but to tune the inductance of the coil so the current/voltage of the coil resonates at a fairly high frequency. It also reduces arching as a freeby but mainly as the voltage across the capacitor is WAY lower (AC voltage) than that across the coil due to L di/dt and
C dv/dt.
I would check out the load for the 48 V supply as to input capacity and put a resistor in series with the load to limit in-rush current to the capacitor when the relay closes. Maybe 0.5 Ohms 2-5 watt? ( for a 500 W supply) Inrush current could be VERY high as the 48 V supply has a large output capacitor and the input of the load probably has some capacitance too. When the relay closes you have a large capacitor charged to
48 V in the power supply and a smaller capacitor across the load at zero volts. Initial inrush is a function of the series resistor which is only a fat piece of wire! Think mili Ohms! In addition, the relay contacts must carry the discharge of the capacitor across the contacts which occurs when a capacitor charged to 48 V discharges through a VERY low resistance relay contact and produces a large current pulse sometimes able to weld contacts together!

 

[Jose_Luis_G]

Be very careful with adding a capacitor across the relay contacts. First, the capacitor across the points of an old auto ignition is NOT to stop arching, but to tune the inductance of the coil so the current/voltage of the coil resonates at a fairly high frequency. It also reduces arching as a freeby but mainly as the voltage across the capacitor is WAY lower (AC voltage) than that across the coil due to L di/dt and C dv/dt.
I would check out the load for the 48 V supply as to input capacity and put a resistor in series with the load to limit in-rush current to the capacitor when the relay closes. Maybe 0.5 Ohms 2-5 watt? ( for a 500 W supply) Inrush current could be VERY high as the 48 V supply has a large output capacitor and the input of the load probably has some capacitance too. When the relay closes you have a large capacitor charged to 48 V in the power supply and a smaller capacitor across the load at zero volts. Initial inrush is a function of the series resistor which is only a fat piece of wire! Think mili Ohms! In addition, the relay contacts must carry the discharge of the capacitor across the contacts which occurs when a capacitor charged to 48 V discharges through a VERY low resistance relay contact and produces a large current pulse sometimes able to weld contacts together!

A small remark to the above is that in the ignition case, the capacitor is not electrolytic. I think that makes a difference.
Anyway I agree that the connection current may affect the contacts of the relay.
According to that, please let me know if this connection schematic is the right one for you.

I would like to call this, building in common!

 

[Grimstod]

I am hooked. I have to make one now. Here is one a friend made. He let me barrow it. Its pretty slick.

 

[Terry Altom]

Question on the water pump. Does it on;y pump in one direction or can I reverse the flow direction by reversing the connections to the 12V power supply?

Just have to connect the pump (test for leaks) and build the shelf/trap door.


Thanks,
Terry