[LawnGnome]

I tested my STEPS how Tangent says from testpoint 4 to 5. and got 21ish V.

So I thought I had 21v+. But after doing some probing, I'm finding that I'm actually get 10.5V from Vout, and -10.5v from GND-out.

Whats going on here?

 

[DaKi][er]

Look at what you are referencing as your ground. If you have your amp that has a virtual ground as your reference, it is going to be pretty much exactly 1/2 way between your power supply's output, which is what you are seeing here. Put the ground probe of your meter to the -'ve output of the power supply and see what you get

Just always keep reminding yourself that voltage is relative

 

[LawnGnome]

Quote:

Originally Posted by DaKi][er /img/forum/go_quote.gif Look at what you are referencing as your ground. If you have your amp that has a virtual ground as your reference, it is going to be pretty much exactly 1/2 way between your power supply's output, which is what you are seeing here. Put the ground probe of your meter to the -'ve output of the power supply and see what you get Just always keep reminding yourself that voltage is relative

I'm measuring from AC ground.

 

[LawnGnome]

I think I might have live and neutral swapped, would this cause this?

 

[LawnGnome]

Now I can only get readings if I connect TP4 to TP5. If I connect TP4 or TP5 directly to AC ground I get no reading.

 

[tangent]

Quote:

Originally Posted by LawnGnome /img/forum/go_quote.gif I'm measuring from AC ground.

Then the measurement is meaningless, because the DC side of the supply is not tied -- on purpose -- to the AC side. This is what it means for a transformer-based supply to be isolated. Nothing on one side can be referred to anything on the other.

 

[LawnGnome]

Quote:

Originally Posted by tangent /img/forum/go_quote.gif Then the measurement is meaningless, because the DC side of the supply is not tied -- on purpose -- to the AC side. This is what it means for a transformer-based supply to be isolated. Nothing on one side can be referred to anything on the other.

OK, But why am I getting negative voltage on the ground out? Won't this damage my PPA?

Are my rectifiers dead?

 

[kklee]

Quote:

Originally Posted by LawnGnome /img/forum/go_quote.gif OK, But why am I getting negative voltage on the ground out? Won't this damage my PPA? Are my rectifiers dead?

I think you're still missing what DaKi][er and Tangent pointed out. You're using an invalid reference point to measure voltages. The output of the STEPS is measured between the +ve (TP4) and ground (TP5). There is no relevance to measuring between either of these connections to any point of the AC side of the power supply because the transformer is isolating the two parts of the power supply from each other.

 

[tangent]

An example: try measuring DC volts from the positive terminal of a AA battery to the negative terminal of your car battery, with the AA battery being held up in mid-air by a friend. What voltage do you suppose you will get?

Answer: It's as pointless a question as trying to measure DC volt from the primary to the secondary side of a transformer that hasn't been tied to a "ground" common to both sides.

 

[LawnGnome]

Ok, But im still getting 42V AC when I measure from TP4 to TP5. Did I fry my rectifiers?

 

[holland]

Quote:

Originally Posted by LawnGnome /img/forum/go_quote.gif Ok, But im still getting 42V AC when I measure from TP4 to TP5. Did I fry my rectifiers?

Do you mean DC? If not, switch to DC. TP4 and TP5 are on the DC side.

 

[LawnGnome]

It should measure very little AC here. It did before, now it measures lots.

On the STEPS page it says you can test it this way.

 

[holland]

For ripple.

 

[LawnGnome]

Quote:

Originally Posted by holland /img/forum/go_quote.gif For ripple.

Exactly, And I'm getting 43V AC.

Instead of the .1mv i used to get.

 

[holland]

So, your whole thread has lost me.

Are you getting the DC voltage you are setting for? Ripple voltage aside. If so, then your STEPS is properly converting to DC at the voltage you are setting. If not, it could be your regulator.

If you are able to measure ripple @ TP4 and TP5 then there's a chance that your regulator (not rectifier) is not working, which should probably show on your DC side.

So, again, are you getting the proper voltage at TP4 and TP5 DC?