How to Set Current Limit and Interpret Indicator Light on Systron Donner HR40-10C?

I just acquired a Systron Donner HR40-10C power supply to use in my shop for various projects.

I was looking for a manual online but it looks like these units haven't been made for years.

I am wondering if anyone has a manual or can give me a quick tutorial on its basic operatoin.  I can get it to run by some combination of turning teh amp dial and at some point the voltage dial kicks in.

I think there is a way to set/limit the amperate.  Do you short the pos-neg with no load//voltage?

Also there is a light between the knobs (see photo) with and I on it.  I assume this is some indicator of current but I am not sure what it means when it is on.

 

Thanks for the help.

It is usually straight forward to set it, and works just as you surmise.
Put a short across the pos and neg terminals, and adjust the current on the meter to whatever you wish to set the limit at. You may need to do it with the voltage control set above zero. My guess is that the light shows up when it is in current limit mode, that is easy to check.
When current limited, the voltage should fall to zero, and the current meter will pin itself to the current set as the limit. With the short removed, it returns the power supply to the constant voltage mode, with the voltage meter pinned at your set voltage, and the current meter indicating load current, between zero and the set limit,
cheers,
Richard

Thanks Richard,

Just went through this exact sequence and it seems to work fine.

The load I have only draws .145 amps so it is difficult to test if it Amp limit. I will find something with a bit bigger amp load and see what happens.


Regards,

David

Another update

I found a 12 V 36 Watt outdoor landscape light.

I used the procedure above and set the unit up to 3 amps. then connected the load and turned the voltage up to 12 Volts. Light worked fine.

I then disconnected and set up the amperage limit to 1.5 amps. then connected the load and dialed in 12 volts. amperage pegged at 1.5 voltage stayed at 12 and the light was dim as expected.

Power supply was humming bit - I assume that would be normal.

Humming is usually noticeable if there are loose lamination in the mains transformer. You can try tightening the bolts that hold and pull the lamination's together if they are accessible. It could also be due to a stressed transformer, there are a number of possibilities, but if the unit is working OK, then it should be OK.
Check the ripple on the output side of the power supply at the highest voltage and current, and see what it is like, if you have a scope.
cheers,
Richard