My Jorney Into The Cnc World.

[John Hasler]

An isolation diode is a diode rated for the supply voltage and full load current in series with the supplies and the load to prevent one supply from reverse-biasing the other if one supply should come on faster than the other. Better would be a reverse-biased diode connected across each supply. That would protect the supplies against reverse bias without passing the load current through a diode in normal operation.

 

[REdington]

An isolation diode is a diode rated for the supply voltage and full load current in series with the supplies and the load to prevent one supply from reverse-biasing the other if one supply should come on faster than the other.

This would be a diode where the 2 PS's are wired together, right.

Better would be a reverse-biased diode connected across each supply. That would protect the supplies against reverse bias without passing the load current through a diode in normal operation.

Would this be a diode across the leads that supplies the 48 volts going to the stepper drivers?????

Thanks for the help
Rodney

 

[John Hasler]

It would be one diode in parallel with each power supply with the cathode of the diode connected to the positive terminal and the anode of the diode connected to the negative terminal of the supply. First check the specifications for the supplies, though. It may be that no diodes are needed.

 

[REdington]

Thanks John, I got it now.


Rodney

 

[REdington]

Got the new stand built. Angle iron and 3/8" plate for the top.








Rodney

 

[markba633csi]

The PS's are fixed and everything works like it should.





Rodney

 

[markba633csi]

I guess what us electronics type folks were wondering was if you grounded your "Com" line to the frame of your system or not? I see the picture with the two supplies wired in series, ONE of them would usually be grounded so your 48 volts has something to "push off" from.
Mark S.

 

[John Hasler]

ONE of them would usually be grounded so your 48 volts has something to "push off" from.

It needs nothing to "push off" from. The circuit just needs to be complete from the power supply positive to load and back to the power supply negative. You might want to connect power supply common to the frame (at one and only one point) but you should not rely on the frame as part of the circuit.

 

[markba633csi]

"Push off from" is probably a poor choice of term, but I have seen cases of instability that can result from floating power circuits that are not "tied down" at one end. Susceptibility to static discharge and such.

 

[REdington]

Since mounting them in the enclosure, I ran the earth ground from the 110 v power cord to the enclosure to ground it. Then I have a earth ground wire to each one of the ground's on the PS's. I haven't tried it yet, but I'm going to try running a wire for the negative side of the 48 volts (just the one PS) to the earth ground and see what happens.

Rodney