ZVS Induction Heater's DC to DC SSR; Protect it from Excessive Current Spikes With Arduino
ฝัง
- เผยแพร่เมื่อ 14 ต.ค. 2024
- Project:
Shut Off DC Power to the 2500 Watt ZVS Induction Heater by turning off the DC to DC
SSR in case an excessive power spike occurs, before it can destroy the SSR.
This is Part 1, of 3 Parts:
I use an Arduino UNO to measure the 75 mv current shunt that is in series with the DC power to the ZVS Induction heater. Here I find out whether there's enough resolution/sensitivity to do the job.
See:
• 2500 Watt ZVS Inductio...
which IS part 3, where I finally solve the problem.
Thanks for the video. I made a foot pedal operates induction heater with the use of an AC SSRelay. No problems handling the current, even without any heatsinking.
What size of induction heater are you using, and what kind of power supply?
I ask these questions because many people who have tried switching the AC have found that, since their power supply can't put out full current immediately, the low initial voltage causes the Mosfets to lock up and destroy parts of the circuit.
@@frenchcreekvalley Thank you for your reply.
I am using the cheapest 2500w model I could find on eBay, combined with "Huawei R4850G2 Rectifier Module 53.5V 56.1A 3000W Communication Power Supply"
I hope that such a supply is appropriate.
Even though the voltage is slightly above what the induction heater is rated, everything works, although a bit hot.
Have you overvolted any of your devices?
Do you think my power supply could be causing the issue you have mentioned?
Looking forward to hearing your thoughts on this. Thanks for your time!
@@Convolutedtubules I do not have any experience with that power supply. But I don't think the 53.5 volts should cause problems. Have you actually measured the voltage? Sometimes the "spec" simply relates to the maximum that the device can output. And--- there is probably some way to adjust the voltage over a narrow range. Try to locate an operator's manual.
The power supply that I use on my 2500 Watt ZVS induction heater is an Emerson R48-2900U. When I apply AC power, it takes about 4 1/2 seconds before it supplies any output at all, so I would not want to use a foot switch to turn it on and off because I don't want to wait 4 1/2 seconds to get it going.
So that's one reason why I want to switch the DC.
@@frenchcreekvalley I believe the rated current and output is accurate as this particular power supply is intended for use inside server rack, for charging backup batteries. Thank you for making me aware of these issues. I will do further testing on the power supply and it's relationship with the relay and heater.
Can I ask how much power is required to melt cast iron like you have demonstrated before and any tips to help me achieve this would be greatly appreciated.
@@Convolutedtubules The 2500 watt setup that I used for melting cast iron drew a maximum of 44 amperes during that test.
Subtracting the 6 amp idle current, that would by about 1800 watts, net, into the work.
Note that I used a graphite crucible for that test. I did that to help maintain the current after the cast iron reached the curie point. This would not be a good idea in practice, because the graphite will be absorbed by the iron, making it even more brittle for use than it was before melting it.
If all else fails, is there a reason not to use an ordinary mechanical relay? That is my back up plan, but is there something waiting to bite me that I haven't considered?
Excellent question! Sure, it can be done.
But here are a couple of the issues with a mechanical relay:
- You have to make certain that the contacts can withstand (in my case) at least 50 amps DC (not AC) at more than 50 volts.
-Such a relay does not come cheap.
-If you are only switching that relay on and off manually, you can probably easily come up with an appropriate power source to energize its coil, but, if you plan to switch it under (Arduino, for instance) program control, you will have to make some sort of additional circuit to get the microcontroller's 5 volt output up to what the relay coil needs.
-You can not drive a mechanical relay with a PWM signal.
-They wear out with time. Every time you actuate it, the contacts get a bit worse.
There's guy out there on youtube, "radio mechanic", I think, who did use an electromechanical relay to power a 1000 watt ZVS heater that was driving a solder pot. I think he finally got it working after one relay failed:
th-cam.com/video/2MY3dAKXmJk/w-d-xo.html
excelent
Great work, so let me see if I get this correct: you have the zvs running, and it has a idle current and a running current when you insert a piece of metal.
See I just am now working of getting my annealer running. so my question is should I run the zvs the whole time and drop the cases out my auto dump, or should I turn the zvs on and off for each case I want to anneal?
Next question is using your three layer/three turn coil water cooled of course @48v should my amperage be 11.1 A approximately? I can't test it with my fluke 87v because it only runs to 10, ush
See I ended up with a bad amp meter, so I'm waiting on a new one, and my SSR was defective from the factory stuck normally closed.
so my coil actually caught the glass cloth on fire when it was running too long me not knowing the SSR was stuck Closed.
One last tining, should I replace the coil, or just re wrap it with new glass cloth?
Any help would be great
If you plan to run cases through one after another, then leave the DC power to the ZVS heater on until you run out of cases.
This assumes that you are water cooling the work coil and fan cooling the circuit board.
I also think you need to pay some attention to the temperature of the your water source. As you can see, I use a fan-cooled radiator, so I can run for hours at a time with water temperatures staying well bellow 150 degrees F. I mention this because I see some folks using a reservoir of only a couple of quarts or less and not having any way to cool that water.
@@frenchcreekvalley Thank you again for the great advice again. I will leave the zvs running. As for cooling I have dual 120mm fans on a aluminum radiator. I didn't have the radiator hooked up to the coil today while I was trying to test my controller to make sure all the switches were working correctly. Do you think that was why the coil got so hot at idle after a couple min?
Yes the coil will get hot very quickly if it is not being water cooled. Some folks have run their systems without any water cooling and the copper tubing gets so hot that the surface oxidizes in just a few minutes. There's an additional penalty for failing to water cool the coil- The heat transfers from the tubing to the nearby capacitors, thereby putting them at increased risk of failure.
When you do connect the cooling water to the work coil, make certain the the incoming water from the pump goes into the BOTTOM of the work coil so the coil fills completely.
@@frenchcreekvalley Wow I never thought of that to make sure it is completely filled. I know about having a vapor lock because of air, I just never thought of it with a coil. Thank you again perfect advice.