Hi Kavitha
I just had a look at the linked data sheet. The application notes show a lot of components in black. It is not clear if these are on the board or not. I assume they are as there is a fair size inductor pictured.
I did note in the input specs
Hot Plug
Unavailable.
Which I would interpret that you should NOT switch power to this unit with your load connected. This device should be powered all the time and switching done on the load side.
I read your post as you are switching the supply to this device when you need the 5V. I don’t think you can do that.
Might be wrong, maybe someone has some experience with this “Mornsun” device. I have never heard of them.
Cheers Bob
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Hi Robert93820,
Thank you for your reply.
We have used all the components that are mentioned in the datasheet (Application note)
Input for the AC DC Converter is taken from the contactor input. It will be connected always. Contactor is driven by the driver circuit
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Hi Kavitha
It is pretty difficult to say without actually being able to observe exactly what is happening.
I would suggest that whatever the contactor is switching has a large inrush current causing a disturbance on the supply line if this converter is connected to supply at all times and not switched.
About all I could suggest is that you find another source for your converter input on a different circuit than that contactor. I am assuming here that the wiring TO that contractor meets all required specifications. If it is too small for the job it is doing you are asking for trouble.
Cheers Bob
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Hi Kavitha,
Which application circuit are you using?
Would it be possible to draw up a diagram of how your system works?
Attached is the block diagram
Hi Robert,
While installation in few locations, we can’t find a input supply nearby so we have taken input from the contactor input itself
Any suggestions on how to reduce the inrush current?
Hi Kavitha.
The motor inrush current will be the same as the stall current. The only practical way to reduce this would be a soft start system. A home made system would not be recommended as I don’t know what this motor is doing and being 3 phase it is probably industrial and quite large.
I hope you are connecting between phase and neutral @ 240VAC and not phase to phase @ 415VAC.
I note you are effectively going through 2 regulators before you get to the ESP32. That should remove any funnies except for a complete drop out.
What is wrong with the external DC supply ?? Have you tried that ??? That should have been the first thing to isolate the problem. What sort of regulator is the 5V to 3.3V device. Linear regulator or a buck converter ?? have you tried running a temporary lead from another 240VAC source ??? These are a few suggestions to isolate where the problem is.
Another thing. Has this system ever worked correctly or is it some sort of new arrangement.
Cheers Bob
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Hi Robert,
The motor is being controlled by both DOL (Direct online) and start delta starters depending on whether it is single phase or three phase motor and we are observing spike in both the cases
The input to the AC DC converter (LS05-26B05R3) is 240VAC in case of single phase motor and 415VAC in case of three phase motor
12VDC to 5VDC and 5VDC to 3.3VDC regulators are of Linear Dropout voltage regulators
We have not tired with external DC supply, let me update if I have any observation
When connecting separate 230VAC source to the AC DC module we observe the same spike
Same setup was working better with electromagnetic relay in place of optoisolator
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Hi Kavitha
It sounds like your set up is upsetting the supply generally or just maybe upsetting the Opto isolator device. “Optocoupler and triac” is a pretty general description, there are several scenarios and I am not going to try and guess which one.
Getting rid of the source may not be feasible.
You may have to revert to a relay. But if driven by any electronic device don’t forget the flywheel diode across the relay coil.
If the external 5VDC supply is a good low impedance source this may fix your problem.
I have seen severe interference on a point to point radio system from the switching spikes of a variable speed very large air supply fan motor in a coal line. The solution… Operate the radio with a large float charged battery bank.
Let us know what using the external 5V supply does. You may have to do both. External supply and relay.
Cheers Bob
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