Induction brass annealer redux

[itchyTF]

Chinese QC?

 

[NearZero]

Should the fan above the induction board be blowing towards the board or the away from it?

 

[Gina1]

I have mine blowing on the board. Have not lost a board in almost 4 years.

 

[NearZero]

Coil not heating up. I've checked the wiring and every thing seems to be working. Timer is working. Power is getting to the heating board but for some reason I'm only getting 0.3 Amps to 1.1 Amps when the it goes through the annealing cycle. Bad power supply? Bad induction board?

 

[itchyTF]

Coil not heating up. I've checked the wiring and every thing seems to be working. Timer is working. Power is getting to the heating board but for some reason I'm only getting 0.3 Amps to 1.1 Amps when the it goes through the annealing cycle. Bad power supply?

Put a different load on the power supply like a suitable resistor or lamp to see if current is correct. I believe you should see about 300ma of current with a 100 watt bulb. If that works it might be the induction board.

 

[David101]

What Voltage power supply are you using it is showing 4.5V at 300 mA Si it is very loaded down. It indicates a short on the induction board. Are the heat sinks touching each other or something else. This was the problem a recent poster found.

 

[NearZero]

What Voltage power supply are you using it is showing 4.5V at 300 mA Si it is very loaded down. It indicates a short on the induction board. Are the heat sinks touching each other or something else. This was the problem a recent poster found.

I'm using 48V 12.5A power supply. I have confirmed that 44V is being supplied past the Packard C230. It only goes down to 4.5V at 300mA when it is on induction cycle.

 

[David101]

You obviously dont have any osscilation and at least one of the mosfets are dead. You have pretty much a short to ground when the induction cycle is on. its a case of checking every component on the board and finding the cause. Or get another board.

 

[itchyTF]

What's the Packard C230?

Not knowing the schematic for the induction board, I'll assume the 48v isn't applied to the switching fets/transistors when not doing induction. If that's the case the induction board may still be bad.

Are any turns of the coil touching?

 

[NearZero]

What's the Packard C230?

Not knowing the schematic for the induction board, I'll assume the 48v isn't applied to the switching fets/transistors when not doing induction. If that's the case the induction board may still be bad.

Are any turns of the coil touching?

I followed the schematic of Gina1. It calls for Packard C230 2 Pole 30 Amp Contactor, 120 Volt Coil. No, the coils are not touching.

 

[itchyTF]

My guess is bad FET(s) / transistor(s).

 

[David101]

My guess is bad FET(s) / transistor(s).

They will be now but what caused the board to not oscillate in the first place? All the diodes need to be checked along with the resistors and the inductors. The boards are not high quality and many have cold solder joints on the inductors.

 

[NearZero]

Put a different load on the power supply like a suitable resistor or lamp to see if current is correct. I believe you should see about 300ma of current with a 100 watt bulb. If that works it might be the induction board.

Did not have a 100 watt bulb but decided to attach a 115V 1.12A motor to Packard Contactor. The voltage meter now goes as high as 6.9 to 7.1A at 48V. So that means there is something wrong with the induction board. Ordered a replacement and will return the damaged board.

 

[NearZero]

I have a few questions regarding the coil. The PC case I used has has a metal grill at the front. Can I drill small wholes on the plate for copper tubbing to pass through and place rubber nipples around the copper tubing for insulation, or should I just cut a big square whole for the copper tubing to pass through? How much clearance is needed?

 

[David101]

You should at least cut a slot between the two holes. There is a good possability that you will cause eddy currents if you dont.

 

[itchyTF]

I believe eddy current could flow around the slot also. FWIW, this is what I did. I believe the material was G10 fiberglas.

 

[NearZero]

Something else must be wrong with my set up. I've replaced the induction board and the coil is not heating up. The board is only drawing 4V and 0.3A. Any suggestions?

 

[itchyTF]

A second bad board?
Can those boards be run with no coil without damage? If so, try it.

 

[NearZero]

A second bad board?
Can those boards be run with no coil without damage? If so, try it.

I don't know if can or can't. While messing round trying to fix the issue with first board I forgot to replace the coil, it make a loud noise when it went through the annealing cycle. This time I just attached the new board from outside the case just to make sure that it wasn't touching anything inside the case and still the same results. Now I'm wondering if that first board was damaged to begin with. Unfortunately I wouldn't know how to test it. Everything else is working fine. Could it be my power supply or the contactor? I attached a 115V 1.12 Amp motor and it drew as much as 7.0A at 48 volts. HELP!

 

[David101]

The boards need the coil to be attached to work. I dont have the circuit in front of me to make a call on if they will destroy components on themselves if the coil is not connected. I think that may be the case however.