Too low resistance load in SMPS

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varunme

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I have a very low resistance (0.33 Ohm) in SMPS, the SMPS is restarting now and then.

The load is 12V 500W 41.67A heater.
The SMPS is 12V 1000W 83.33A

How can we correct the situation and system goes normally?
 

So now in total 3 SMPS?

yes three SMPS. two cheap and a branded one


What does "restarts in a moment" mean?

Restarts Just after the fan of the SMPS starts spinning


What are "this kind of heaters"?

Low resistance heaters

What does "behaves like this" mean?

SMPS behaves abnormally


If two different SMPS show the same behaviour ... it's likely that the problem is not caused by the SMPS at all. Thus we need to discover the whole setup.

Ok

All in all the given information's are vague, makes a detailed help impossible.
If you still need help, then provide clear informations:

Ok

* exact type of heater, with link to datasheet
This is custom made, I will get the wiring inside and datasheet of the heater soon from manufacturer
(12v 500w titanium heater, sorry I typed wrong as tungsten heater)

* exact type if each SMPS, each with link to datasheet, each with clear information how it behaves
Branded one https://www.meanwell.com/productPdf.aspx?i=909
Cheap one VENERGY, didn't found the datasheet, I am searching

* sketch of wiring
will share the circuit soon

* photos of the whole test circuit, where we can see which wire goes where
will share soon

* how do you test it? What test equipment do you use?
Testing with just series connection, will share the connection diagram soon

* additional informations like (expected) tungsten temperature

I will update with the missing informations soon
--- Updated ---

So now in total 3 SMPS?
yes two cheap and one branded

What does "restarts in a moment" mean?
the fan on SMPS spins and restarts

What are "this kind of heaters"?
low resistance heaters

What does "behaves like this" mean?
behaves abnormally

If two different SMPS show the same behaviour ... it's likely that the problem is not caused by the SMPS at all. Thus we need to discover the whole setup.

Ok

All in all the given informations are vague, makes a detailed help impossible.
If you still need help, then provide clear informations:

* exact type of heater, with link to datasheet
12V 500W titanium heater ( sorry I wrongly typed as tungsten, I will get the datasheet soon
it is custom made

* exact type if each SMPS, each with link to datasheet, each with clear information how it behaves
Branded MW 750W https://www.meanwell.com/productPdf.aspx?i=909
Cheap : VENERGY 1000W, Didn't got datasheet, I am searching.


* sketch of wiring
Will update soon

* photos of the whole test circuit, where we can see which wire goes where
Will update soon

* how do you test it? What test equippent do you use?
just connected SMPS in series with heater( will share circuit diagram soon)

* additional informations like (expected) tungsten temperature

I will update with missing informations soon
 
Last edited:

This is an absurd thread. I’ve seen a lot of nonsense on this board, but this is right up there.

The heater manufacturer will design a SMPS ‘JUST FOR YOU’ to “suit this particular heater”??? You mean they don’t already have an SMPS for “this particular heater”? What’s so special about THIS heater? Why do they suggest a ”transformer PSU”?

I think I’m done here, there’s just a complete lack of intelligent information.
 
I agree with Barry.

There is no heater datasheet, nor a partnumber.
Same with power supply.

Still don't see how you check operation/shutdown at all. Did you do voltage measurement, current measurement, which measurement device?


the fan on SMPS spins and restarts
Once? Repeatedly? And then?
"The fan spins" isn't realy a test method. Some SMPS don't have a fan at all. Some fan start at power up, then remain silent until overtemperature, some do it ...

Klaus
 
Yes, barry they may be wrong or they are confusing me, I am checking the whole setup,
Initially I thought there will be problem in heater + SMPS setup, now the support from KlausST and barry gained confidence on the setup. There may be problem in the whole setup, I am thoroughly testing the setup. I will keep updating here.


Qn: <<"Still don't see how you check operation/shutdown at all. Did you do voltage measurement, current measurement, which measurement device?"
"
Once? Repeatedly? And then?
"The fan spins" isn't realy a test method. Some SMPS don't have a fan at all. Some fan start at power up, then remain silent until overtemperature, some do it ..." >>

Ans: Actually I take hint from fan and LED on SMPS, I have checked voltage also, voltage is zero when shutdown, using multimeter.
 

Have you tried a simple crude roughly-right-voltage supply, which
would be free of such "behaviors" and allow you to investigate what
the heater load is doing?

Maybe it has a bang-bang thermostat which provokes demand surges,
and that surge trips your OCP or even output OVP due to "reasons".
Instrument up the load and know what you're up against.

Or maybe the dumb (like xfmr + full wave bridge + fat caps) power
supply is just fine and dandy, and you're done.

Driving a heater with a high accuracy (?) power supply seems like
a waste of money.

For that matter what about plain AC, via xfmr, and be done?
 

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