12v zvs induction heater

[Ceejayschmitt]

Hi, I’m new here so hope this is in the right place.

today I set up my mini induction heater I got from amazon. Link below.

All that is needed, as you probably know, is to fit the coil. I’ve tried it in the connector block and soldered directly to the plates. But when ever I connect my variable power supply voltage drops to around 0.4v. Any idea what is going on or what I’m doing wrong?

HALJIA 5~12V ZVS Low Voltage Induction Heating Power Supply Tesla Driver Board Module With Coil https://www.amazon.co.uk/dp/B07426L4KC/ref=cm_sw_r_cp_api_fabc_rRFaGbZNKEJ4D?_encoding=UTF8&psc=1

 

[ChrisP58]

In your link, it says 120 Watts. At 12 Volts, that will be 10 Amps.

Can your variable power supply deliver that much current?

 

[Ceejayschmitt]

Yes it can supply a maximum of 10A although I did see it creep over that earlier. When I increased to 10A I managed to get about 2.something volts supply then but then my coils (at least I think it was) started to smoke so I turned the current back down

 

[ChrisP58]

If the load needs 10 Amps, then the supply should be able to deliver more than 10. Particularly for a switchmode power device (which your induction heater is). It may need pulses of current many times the 10 Amps average.

 

[Ceejayschmitt]

I have watched a few videos of people using this model earlier and one in particular was only drawing 0.7A at 12v and was able to quickly heat a small screwdriver. But I cannot get close to 12v. And I can’t seem to figure why.
As I said I only got between 2 and 3 volts at 10 amps. But then I don’t see how it can handle 10 amps if it starts to smoke within a few seconds.

 

[ChrisP58]

It sounds to me like your power supply is going into current limit. Answers to the following questions will help me to better understand the problem.

What is your power supply?
Does it output the correct voltage (12V?) before you connect it to the induction heater?
Does it deliver 10 Amps at (12?) Volts when connected to some other load that will draw that much current?

As for the unit smoking at 2-3 volts. That is about the turn on threshold for many mosfets, so they are just barely turned on. When mosfets are barely turned on, they don't handle power very well.

 

[Ceejayschmitt]

Hi, thank you for your continued help. I have placed a link for my power source below.

Yes it outputs correct voltage of 12V before I connect it to the heater. When I connect it, I’m getting 9.6A at 2.7V and yes it is limiting the current.

I have only just got this power supply so haven’t used it for much else.

DC Power Variable Supply 30V 10A 4Digital Display Adjustable Regulated Switching Power Supply with Leads Power Cable https://www.amazon.co.uk/dp/B08HQG9D56/ref=cm_sw_r_cp_api_fabc_I7UaGb57AEVBE?_encoding=UTF8&psc=1

 

[rjenkinsgb]

I'm guessing the thing just takes a very high current with both power devices conducting to some extent, until oscillation starts.
Your power supply appears to be current limiting before the voltage reaches the point oscillation starts.

Having a large electrolytic cap connected across the PSU output before the power board is connected, so there is a source for the initial start-up current may work; or the device could just be a dud; those circuits are extremely primitive have no protection for the power devices at all.

 

[shortbus=]

get about 2.something volts supply then but then my coils

If your meaning the induction coil, it will smoke the first time you use it, it's making heat.

Here is the best source I've found about making ZVS induction heaters work. The guy destroyed many power supplies and ZVS modules before finding out what works or not. If your interested in making one that really works it will be worth the time to watch his videos! https://www.spaco.org/Blacksmithing/ZVSInductionHeater/1000WattZVSInductionHeaterNotes.htm

 

[Ceejayschmitt]

Thank you, I will take a look at that now.
No it wasn’t the induction coil starting to smoke. It was the two coils mounted to the circuit.