Power supply regulator?

[DennisCNC]

Any one here built a regulator for a dc power supply ? I have a hard time finding a transformer to have ~70v DC so I need to build a regulator to have a steady output. Also the wall voltage is 165v AC in my shop and house.

Thanks

[martinw]

Dear Dennis,

I am not being a smart-#ss, but if you could tell all hereabouts what you want to achieve in a bit more detail, everybody will pile in.

We know your AC supply.... give us the rest.

Best wishes,

Martin

[gar]

080212-0840 EST USA

DennisCNC:

How do you run any normal equipment on 165 V sine wave RMS line voltage? Such as a 120 V incandescent lamp. Or a 120 V induction motor. Neither of these will live very long. Nor will the transformer in your power supply if its nominal primary rating is 120.

If the load on your DC power supply does not require regulation, then do not regulate, but use a transformer with the correct ratio.

As said above provide more useful information on details.

.

[vger]

At first I wondered what country do you live in, looked and saw Clearwater Florida. Hmmm, Ohhhhhh you are talking "peak" voltage value of about 115 V RMS. Take the 115 V line voltage rectify it and put a cap across it and you get about 165 V DC.

Yep, more info needed. What are you running? How much current is required?

Let us know, we will help.

Steve

[Al_The_Man]

You did not mention what VA, and do you really need regulated?
For the correct secondary voltage, I usually buy from the Ebayer that manufacturers toroid's and get as close as possible in voltage and take a few turns off.
That is if you are intending on a Linear supply.
Al.

[DennisCNC]

That is why i'm wondering why the line voltage is 165v maybe it was a high volt day or something. I checked another day it was 125v in the wall. So the transformer I have will do as the rectified and filtered DC voltage is ~80 and not ~95 like it was before. I still might need a regulator in case the voltage goes up again. I need about ~5amp max at ~80vdc max for the regulator to handle. Are there regulators like the lm317 but for the higher voltage and current?

[gar]

080212-1911 EST USA

DennisCNC:

If you actually had 165 V and other equipment was connected to this circuit, then you would have burned out components.

Let's suppose you have a single phase 120-0-120 service and if you have a bad nuetral connection (high resistance) anywhere from the pole to point of use, then you might have all sorts of different voltages anywhere from 240 to 0 depending upon the relative loading between the two sides of the pole transformer secondary.

We had an intermittent of this type at the pole connection, not very often, but created problems when it occurred. But nothing like 165 V. Maybe our high value was 135 V.

Today I think that most people that are in good service areas will have voltage in the range of 115 to 125. At my home it is usually about 121 and at the shop about 123.

.

[Al_The_Man]

Beware if using a Fluke meter, when the battery starts getting low, strange things happen, I have seen as high as 200 volts 'measured' on a 120v ac circuit due to low battery.
Al.

[martinw]

Dear Al The Man,

Crazy bug! (Top left)

Best wishes,

Martin