DC - DC Convertor Question 1

[unclebob]

Hello all!

Have a quick one here:

We have a converter ASTEC LPS155 that can be feed 100-120V ac or up to 250 dc. Output is 48 V dc.

On the input connector, there are three (3) pins:

1- Ground
2- Live
3- Neutral

There are no (+) or (-) signs. Since we're feeding it
with 250 V dc, where (+) and (-) leads connect?

I blow one converter with (+) lead on neutral and (-) lead
on live, and I don't want to blow a second one. Any help?

Thanx

 

[bklauba]

Do you have a voltmeter?

 

[waross]

Hello unclebob;
Here is the info sheet from Astec.

http://www.astec.com/products/datasheets/lp/lps150revb.pdf

I phoned technical support. I got through almost immediately.
I got an excellent responce fom the technical person.
(case #31863)
The connections are: Positive to Line. Negative to Neutral.
There is an internal fuse that may have saved your convertor.
The replacement is a 5 Amp, 20 mm, Quick-Acting fuse.
yours

 

[unclebob]

Thanks waross, you're very helpful, as usual!

 

[itsmoked]

waross; Why didn't you ask them why it matters? I can't imagine any reason why feeding a rectifier bank would matter... Can you?

I would rather think that the inrush of charging the front end by a "snapped on" 250Vdc blasted the fuse.

uncle; you may need to install a resistor or some other device to limit the inrush if your fuse mysteriously blows occasionally.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[GTstartup]

I am wondering why, in the absence of firm information, would your first try be (+) to neutral and (-) to "live".

Just curious.

 

[Skogsgurra]

Me too. It shouldn't matter, really. The AC mains is changing polarity 100 or 120 times per second. So you should be able to connect either way.

Gunnar Englund

http://www.gke.org

 

[waross]

Hello itsmoked, GTstartup, and skogsgurra.

Hello waross; Why didn't you ask them why it matters?

I can't think of a reason either. I wish that I'd asked.
sorry
respectfully.

 

[itsmoked]

Hey waross nothing to be sorry for.. You did more than any of us!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[boreholelogger]

Active is the (+) connection and the neutral wire (-) usually ends up being connected to the ground stake at some point.

 

[OperaHouse]

"feed 100-120V ac or up to 250 dc." This is not correct. I was able to ind a picture of the ASTEC LPS155 and the label says 100-127AC, 200-250AC, DC 220-300, and that jumpers must be changed. This unit has a voltage doubler for low voltage. There certainly could be some problems if the jumper was not switched from voltage on the caps.