DPS5020 SMD fuses blowing with CC power supply

[drummerdimitri]

I have a meanwell 48V constant current power supply feeding my DPS5020 set to 50V and when connected to the inputs at the rear and turn on the switch on the unit, some of the 20A ceramic smd fuse blew.

I'm not sure the reason for this. Should I lower input voltage? I've used this combo before without any issues from memory and now I'm not sure why it is behaving this way.

Waiting on some replacement fuses, in the meantime what could of been the cause of this?

[rs20]

What do you have the CC supply current limit set at?

Do you turn the supply on, and then connect the load? Or do you connect the load, then enable the supply?

[drummerdimitri]

What do you have the CC supply current limit set at?

Do you turn the supply on, and then connect the load? Or do you connect the load, then enable the supply?

Since it is a constant current source, it will by default try to push 21A into the unit if possible and that cannot be adjusted.

The only thing I can change is the max voltage  the meanwell can supply and the rest is all ohms law.

I connect the power supply to the module, turn on the power supply and then turn on the module via the switch at the back with no load connected.

Could it be there is a larger than 20A inrush current while doing so? Should I try lowering the input voltage to reduce that current somehow 

[rs20]

Sometimes these supplies have bugs where they provide big inrushes of current or voltage spikes when they start up.

Sometimes these supplies have capacitors at the output (yes, even nominally CC supplies) and thus connecting the load while the supply is on will create a spike of current.

So there's no 100% reliable rule, but the general rule is that you should switch on your power supply, but have the output disabled, connect the load, and then enable the output.

A 21A supply will not blow a 20A fuse. But you should really power this thing which a much smaller input, and debug why so much current is being drawn. Clearly the DPS5020 needn't be drawing 20A * 48V = 1000W of power, especially if you have no load connected.

[prasimix]

If that is not a secret can you please let me know which Mean Well model you are using?

[bloodhunter007]

when the input has big power , when you input power was turn on first, then connect the DPS5020, the fuse was easy to be damaged
for the right way, you should connect them all first, then turn on
for fuse, it is 20A fuse , you can replace, if you have any question, you can contact that designer 1749808860@qq.com

[bloodhunter007]

you are right , you find the problem, when the input power have big power, when you connect it when it have power,. there will be some Current reverse irrigation, it will damage the fuse

[bloodhunter007]

What do you have the CC supply current limit set at?

Do you turn the supply on, and then connect the load? Or do you connect the load, then enable the supply?

Since it is a constant current source, it will by default try to push 21A into the unit if possible and that cannot be adjusted.

The only thing I can change is the max voltage  the meanwell can supply and the rest is all ohms law.
that is the connection problem, don't need to change other fuse

I connect the power supply to the module, turn on the power supply and then turn on the module via the switch at the back with no load connected.

Could it be there is a larger than 20A inrush current while doing so? Should I try lowering the input voltage to reduce that current somehow 

[thedoc298]

I know this is old post, I have 3 of the dps5020, anytime I connect a well filtered dc source 40-50 volts to the unit and turn on the rocker switch of the unit, the fuse pops. Tired of changing fuses so have to use variac to to limit supply to 30 volts dc. I can then turn up the supply voltage. This is a pain to always have to use a variac. More of a pain if I forget to reduce voltage.