Products > Test Equipment

New DL24EW and DL150W load testers from Atorch.

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thm_w:
Its a good observation though.

With a 5A load I measure: 0.299V, 0.299V across 0.25R and 0.288V, 0.286V across 0.22R
So 1.2A and 1.3A, about 8% difference as you had predicted.

Filippo52:
OK
Thanks for your attention.
I would like to point out that the official Atorch seller claims that the choice of putting different resistors on the two sides is a precise choice precisely to optimize the balance and that it costs more to put different resistors but this way they get the balance and they sent me a photo thermal that I am attaching to you.



I find this thing very strange and I told him that I have measured different currents and now you confirm this thing,
If the currents are different and are greater on one side, that side will have more heat dissipation and so what are they sustaining and why?
I also looked at the photo they sent. It can also be seen by eye but with Photoshop I verified that the left side (seen from below, in my case it is the side with the lowest resistances and the highest currents) has a lighter shade of yellow, a sign of a slightly higher temperature.

Who knows if they will be convinced that by putting different resistors they make a mistake?

or is there some mystery?

thm_w:
Maybe on an earlier design, there was a bigger difference between the FETs with actual justification for it. And they just left it in, even though its no longer needed?
Or whoever tested it had screwed up the thermal paste.

I wouldn't overthink it.

SpottedDick:
If it's like the original DL24, you can calibrate it out anyway?
Of course, first put a meter on it and see if it's already accurate :)

Can you get the model number of the MOSFETs?

Filippo52:
Thanks SpottedDick,
but the problem is not the calibration but rather getting the maximum power dissipation. You can get this maximum only if the 4 mosfets work at the same temperatures otherwise the hottest ones will be the first to die followed by the others.
By changing the heatsink with something much more robust, even keeping its fan at 150 W, you can get there.
Currently I have arrived at 80 W with 40 °C with those ridiculous heatsinks that they put in and therefore even if it is not the temperature of the mosfet I think it is still a safety temperature. I have had it for a long time without any problems. By placing a 400 gr heat sink (8cmx8cmx 5cm heigth), a 50-55°C could be obtained with 130-150 W dissipated.
I test these days and then I come here to report

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