Programmable vs. "knob" power supplies

[CC]

Hi:

I returned my Protek 3044T power supply, which I didn't like because
it's impossible to set low current limits precisely. Partly due to the
0.01A resolution meters, but also the knobs are linear. And at low
currents there was a large 2x discrepancy between the setpoint and
actual limit (actual lower than limit). Finally, the one I received at
home buzzed when I turned it on because a transformer cover was not
secure and not easy to fix.

I'm also likely to dump my Protek 1805 power supply on Ebay. Anybody
want it for 60% of the $193.80 purchase price (not incl. shipping)?

At least Xantrex puts logarithmic current control pots in their "knob"
type power supplies.

But also, I found that the Protek supplies get screamin' hot even at
currents of about half the rating. This bugs me. I don't like designs
that push the limits of component temperature.

I regret trying to save money with the Protek supplies. More than half
of the time I try saving money I wind up sending junk back, wasting a
bunch of time&shipping charges. Almost never do I regret buying
something with a hefty price tag but clearly superior quality.

I'm now inclining toward programmable supplies only, because I'm getting
hooked on the digital settability after getting an Agilent E3631A and a
Xantrex XDL35-5 at work. Agilent user interfaces leave much to be
desired, though.

The Xantrex is one precise power supply! And the user interface is very
good as well. Monday I should give it a heavy load test to see how the
heat is.

What I need is a logic level supply that can do at least 18V 5A, and a
dual supply that can do at least 30V 2A.

I was considering replacing the Protek 3044T with a Xantrex XPL30-2D
"knob" supply. This would be adequate for +/- rails for linear type
circuit experimenting, and their log pots should avoid the low current
settability problem of many knob-set supplies.

http://www.testequity.com/products/1147/

Then splurge on the $815 Xantrex XDL35-5 for the logic supply. The
thing that bugs me is that the Xantrex doesn't have a computer interface
unless I pay $1025 for the XDL35-5P model. Ouch!

http://www.testequity.com/products/1148/

For that money, it makes me consider instead to look at the Instek
PSM-3004 or PSM-6003 which have standard interfaces for more versatility
in terms of voltage and current range. But then again, I have more use
for the Xantrex's 0.1mA lower end precision.

http://www.testequity.com/products/1310/


So many choices; Ugh!



--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

 

[Luhan]

CC wrote:

Hi:

I returned my Protek 3044T power supply, which I didn't like because
it's impossible to set low current limits precisely. Partly due to the
0.01A resolution meters, but also the knobs are linear. And at low
currents there was a large 2x discrepancy between the setpoint and
actual limit (actual lower than limit). Finally, the one I received at
home buzzed when I turned it on because a transformer cover was not
secure and not easy to fix.

I'm also likely to dump my Protek 1805 power supply on Ebay. Anybody
want it for 60% of the $193.80 purchase price (not incl. shipping)?

At least Xantrex puts logarithmic current control pots in their "knob"
type power supplies.

But also, I found that the Protek supplies get screamin' hot even at
currents of about half the rating. This bugs me. I don't like designs
that push the limits of component temperature.

I regret trying to save money with the Protek supplies. More than half
of the time I try saving money I wind up sending junk back, wasting a
bunch of time&shipping charges. Almost never do I regret buying
something with a hefty price tag but clearly superior quality.

I'm now inclining toward programmable supplies only, because I'm getting
hooked on the digital settability after getting an Agilent E3631A and a
Xantrex XDL35-5 at work. Agilent user interfaces leave much to be
desired, though.

The Xantrex is one precise power supply! And the user interface is very
good as well. Monday I should give it a heavy load test to see how the
heat is.

What I need is a logic level supply that can do at least 18V 5A, and a
dual supply that can do at least 30V 2A.

I was considering replacing the Protek 3044T with a Xantrex XPL30-2D
"knob" supply. This would be adequate for +/- rails for linear type
circuit experimenting, and their log pots should avoid the low current
settability problem of many knob-set supplies.

http://www.testequity.com/products/1147/

Then splurge on the $815 Xantrex XDL35-5 for the logic supply. The
thing that bugs me is that the Xantrex doesn't have a computer interface
unless I pay $1025 for the XDL35-5P model. Ouch!

http://www.testequity.com/products/1148/

For that money, it makes me consider instead to look at the Instek
PSM-3004 or PSM-6003 which have standard interfaces for more versatility
in terms of voltage and current range. But then again, I have more use
for the Xantrex's 0.1mA lower end precision.

http://www.testequity.com/products/1310/


So many choices; Ugh!



--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

You probably won't go running out to get one like mine...

http://members.cox.net/berniekm/Bench.html

This design features marginal regulation and output ripple. Its one
real nice feature is a current limit cutout. You set it in .01 A
increments up to 4 amps. When it senses the limit, it just shuts off.
This all but eliminates the 'constant current cookout' when the circuit
I'm designing screws up.

Luhan

 

[Jim Thompson]

On 29 Jul 2006 16:02:36 -0700, "Luhan" <luhanis@yahoo.com> wrote:

CC wrote:
Hi:

I returned my Protek 3044T power supply, which I didn't like because
it's impossible to set low current limits precisely. Partly due to the
0.01A resolution meters, but also the knobs are linear. And at low
currents there was a large 2x discrepancy between the setpoint and
actual limit (actual lower than limit). Finally, the one I received at
home buzzed when I turned it on because a transformer cover was not
secure and not easy to fix.

I'm also likely to dump my Protek 1805 power supply on Ebay. Anybody
want it for 60% of the $193.80 purchase price (not incl. shipping)?

At least Xantrex puts logarithmic current control pots in their "knob"
type power supplies.

But also, I found that the Protek supplies get screamin' hot even at
currents of about half the rating. This bugs me. I don't like designs
that push the limits of component temperature.

I regret trying to save money with the Protek supplies. More than half
of the time I try saving money I wind up sending junk back, wasting a
bunch of time&shipping charges. Almost never do I regret buying
something with a hefty price tag but clearly superior quality.

I'm now inclining toward programmable supplies only, because I'm getting
hooked on the digital settability after getting an Agilent E3631A and a
Xantrex XDL35-5 at work. Agilent user interfaces leave much to be
desired, though.

The Xantrex is one precise power supply! And the user interface is very
good as well. Monday I should give it a heavy load test to see how the
heat is.

What I need is a logic level supply that can do at least 18V 5A, and a
dual supply that can do at least 30V 2A.

I was considering replacing the Protek 3044T with a Xantrex XPL30-2D
"knob" supply. This would be adequate for +/- rails for linear type
circuit experimenting, and their log pots should avoid the low current
settability problem of many knob-set supplies.

http://www.testequity.com/products/1147/

Then splurge on the $815 Xantrex XDL35-5 for the logic supply. The
thing that bugs me is that the Xantrex doesn't have a computer interface
unless I pay $1025 for the XDL35-5P model. Ouch!

http://www.testequity.com/products/1148/

For that money, it makes me consider instead to look at the Instek
PSM-3004 or PSM-6003 which have standard interfaces for more versatility
in terms of voltage and current range. But then again, I have more use
for the Xantrex's 0.1mA lower end precision.

http://www.testequity.com/products/1310/


So many choices; Ugh!



--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

You probably won't go running out to get one like mine...

http://members.cox.net/berniekm/Bench.html

This design features marginal regulation and output ripple. Its one
real nice feature is a current limit cutout. You set it in .01 A
increments up to 4 amps. When it senses the limit, it just shuts off.
This all but eliminates the 'constant current cookout' when the circuit
I'm designing screws up.

Luhan

If you ain't got a button you must be a knob ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[CC]

Luhan wrote:

You probably won't go running out to get one like mine...

http://members.cox.net/berniekm/Bench.html

This design features marginal regulation and output ripple. Its one
real nice feature is a current limit cutout. You set it in .01 A
increments up to 4 amps. When it senses the limit, it just shuts off.
This all but eliminates the 'constant current cookout' when the circuit
I'm designing screws up.

No, I probably won't. I built a dual 28V 5A supply using LM338K
devices. I don't like the foldback limiting that wreaks havoc on
anything which draws brief current surges. Also, no current limit
setpoint at all.

I don't have time to build everything anymore, so now I'm willing to pay
for test instruments and spend the rare hours here and there on
something that can't be purchased.


Good day!



--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

 

[Matt J. McCullar]

I'm no fan of Protek, either. My workplace bought half a dozen of the same
model (the exact model number escapes me, though it is a dual-polarity,
analog-adjustable type with digital LED readouts) brand-new several years
ago, and all fix of them failed within a year. We fixed them ourselves and
"improved" them slightly, and they haven't given us much trouble since. But
they do seem to break rather easily.

 

[CC]

Matt J. McCullar wrote:

I'm no fan of Protek, either. My workplace bought half a dozen of the same
model (the exact model number escapes me, though it is a dual-polarity,
analog-adjustable type with digital LED readouts) brand-new several years
ago, and all fix of them failed within a year. We fixed them ourselves and
"improved" them slightly, and they haven't given us much trouble since. But
they do seem to break rather easily.

Oh my, that's not a good stat. Have you any experience with Instek, or
Xantrex?



Thanks for input.

Good day!



--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

 

[John Jardine.]

"CC" <somewhere@overthe.rainbow.net> wrote in message
news:eagn7p02fb8@news1.newsguy.com...

Hi:

I was considering replacing the Protek 3044T with a Xantrex XPL30-2D
"knob" supply. This would be adequate for +/- rails for linear type
circuit experimenting, and their log pots should avoid the low current
settability problem of many knob-set supplies.

http://www.testequity.com/products/1147/

I've used a XPL30-2D for a couple of years. Works well. The log current pot

is approximated using 3 linear track segments and is very human friendly.
Biggest drawback is voltage setting. The 'course' pot is single turn and
runs 0-30V. It's soooooo easy to catch the knob and suddenly power those
expensive 5V components from 20V. Voltage knobs now held in a mastic gunge.
Unsightly but slows 'em down.
Single 5 or 10 turn pots, would have improved the ergonomics no end.
(Though as with most modern products, function is subserviant to form).
john

 

[CC]

John Jardine. wrote:

"CC" <somewhere@overthe.rainbow.net> wrote in message
news:eagn7p02fb8@news1.newsguy.com...
Hi:

I was considering replacing the Protek 3044T with a Xantrex XPL30-2D
"knob" supply. This would be adequate for +/- rails for linear type
circuit experimenting, and their log pots should avoid the low current
settability problem of many knob-set supplies.

http://www.testequity.com/products/1147/

I've used a XPL30-2D for a couple of years. Works well. The log current pot
is approximated using 3 linear track segments and is very human friendly.
Biggest drawback is voltage setting. The 'course' pot is single turn and
runs 0-30V. It's soooooo easy to catch the knob and suddenly power those
expensive 5V components from 20V. Voltage knobs now held in a mastic gunge.
Unsightly but slows 'em down.
Single 5 or 10 turn pots, would have improved the ergonomics no end.
(Though as with most modern products, function is subserviant to form).
john

Why is the form superior with the coarse/fine scheme instead of a
10-turn. This constantly bugs me about most linear supplies. I put a
10-turn on my power supplies. I suppose they save a few $. But at a
large cost in function, as you say. Why don't designers tell their
bosses to shove it, and argue for a superior product?

Have you checked if the XPL30-2D appears possible to modify with 10-turn
pots to replace the coarse V and I pots (abandoning the fine V)? Protek
had the pots on a PCB mounted to the front panel, so such a mod was
hopeless.

I tend to be disappointed by the slightest deficiency in things, making
me wish I had just spent more for something better, or considering the
"perfect" design to build myself.

I'm getting close to considering the $1290 dual XDL35-5T for the +/-15V
stuff. Though I don't know why they didn't bother to make the 3rd
output programmable and more substantial. If they had made it 0-6V at
5A or something, it would be an Agilent E3631A killer for sure.

So I tend to consider the XDL35-5T really only a dual. Maybe try a
cheaper $375 B&K 1785B perhaps for the logic supply.

The ultimate setup would be the XDL35-5T and the Instek PSM-3004.

Good day!

--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

 

[Genome]

"CC" <somewhere@overthe.rainbow.net> wrote in message
news:eagn7p02fb8@news1.newsguy.com...

Hi:


So many choices; Ugh!

--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

Would TTi have something of use to you?

http://www.tti-test.com/

DNA

 

[CC]

Genome wrote:

"CC" <somewhere@overthe.rainbow.net> wrote in message
news:eagn7p02fb8@news1.newsguy.com...
Hi:


So many choices; Ugh!

--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

Would TTi have something of use to you?

http://www.tti-test.com/

DNA

Strange. That's the first time I have seen supplies that are identical
to the Xantrex line but with another brand label. There are also some
other models not in the Xantrex line, but clearly drawing on the same
designs, such as the single out TSX series. I have the Xantrex
equivalent of the dual CPX at work, and the QL as well. The CPX is a
supply if a bit of switcher noise can be tolerated. Gets much quieter
with a little 100uF low ESR cap on the output terminals. I just love
the QL.

I wonder who's really designing and manufacturing these things?

Hmmpff, I suppose they could be Genome's progeny!

I think Monday I'll just purchase the Xantrex XDL35-5 (equiv to TTI's
QL355) and a XPL30-2D (equiv to TTI EL302D)

Considering the $/UKpound exchange rate, the prices in the US seem to be
a bit higher than UK. Perhaps they are of UK/Euro origin?

My compliments to whomever designed the XDL35-5/QL355 series, and the
CSX for that matter.

The "knob" supplies just need 10-turn pots for V and I adjust, then
they'd be perfect.


Good day!



--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

 

[Genome]

"CC" <somewhere@overthe.rainbow.net> wrote in message
news:eaissv02df9@news3.newsguy.com...

Genome wrote:
"CC" <somewhere@overthe.rainbow.net> wrote in message
news:eagn7p02fb8@news1.newsguy.com...
Hi:


So many choices; Ugh!

--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

Would TTi have something of use to you?

http://www.tti-test.com/

DNA

Strange. That's the first time I have seen supplies that are identical to
the Xantrex line but with another brand label. I wonder who's really
designing and manufacturing these things?

Hmmpff, I suppose they could be Genome's progeny!

I think Monday I'll just purchase the Xantrex XDL35-5 (equiv to TTI's
QL355) and a XPL30-2D (equiv to TTI EL302D)


Good day!

Oh.... right

Yes, I was there for a while but have no responsibility for any product.

As far as I know it was all designed in the UK by TTi, or through external
sources working for the company. There was some marketing/sales cross link
for product with Xantrex so some swappage of ideas may have occured.

Hmmmm, so it's shit?

I'll shut up now....

DNA

 

[John Jardine.]

"CC" <somewhere@overthe.rainbow.net> wrote in message
news:eaip4k020nh@news1.newsguy.com...
[...]

Have you checked if the XPL30-2D appears possible to modify with 10-turn
pots to replace the coarse V and I pots (abandoning the fine V)? Protek
had the pots on a PCB mounted to the front panel, so such a mod was
hopeless.

Sadly, (lke the Protek) the pots are mounted on a big front panel PCB. Could
drill through I suppose but there's about a dozen tracks that would then
need linking through. A hopeless case
john

I tend to be disappointed by the slightest deficiency in things, making
me wish I had just spent more for something better, or considering the
"perfect" design to build myself.
[...]

Last year, mail ordered a standard, mini tower, PC case. Front panel a
swirl of artistic, post-modern, sculpted mouldings.
Can't though f*****g eject a floppy disc. Disc has to be teased out of the
artistic mouldings using long nose pliers.
The PC and programming world seemingly survives with secondrate as a norm.
Yet a powertool company (as a real world example) would only last months if
a similar attitude to users needs was adopted.
john

 

[Joerg]

Hello Chris,

Whatever you buy test it for load change spikes. A client of mine got
burned by that, big time. I actually had to come out there.

What surprised everyone was that my old Russky power supplies did not
exhibit that problem at all. These also were difficult to adjust but I
swapped the pots for 10-turns plus nice mechanical counters.

John Larkin had once pointed these out:
http://www.lascarelectronics.com/PRODUCTS.CFM?STOCKNO=PSU%20130&CFID=1158288&CFTOKEN=eb3e41f04e3ece25-842A2914-15C5-5FA1-624EDD23F58C010D

No idea how they deal with load changes, hopefully John will let us know
some day when he has run the supplies through the paces.

--
Regards, Joerg

http://www.analogconsultants.com

 

[Ben Jackson]

On 2006-07-29, Luhan <luhanis@yahoo.com> wrote:

You probably won't go running out to get one like mine...

http://members.cox.net/berniekm/Bench.html

This design features marginal regulation and output ripple.

I started building a design like this after seeing something similar on
the net (software controlled regulation), but during testing I decided
that the response time to shifting load current was just never going to
be fast enough with a microcontroller. Have you done any torture tests
on your supply to see how well it regulates under variable load?

--
Ben Jackson AD7GD
<ben@ben.com>
http://www.ben.com/

 

[Joel Kolstad]

Hi John,

"John Jardine." <john@jjdesigns.fsnet.co.uk> wrote in message
news:eaj489$d7m$1@newsg1.svr.pol.co.uk...

Last year, mail ordered a standard, mini tower, PC case. Front panel a
swirl of artistic, post-modern, sculpted mouldings.
Can't though f*****g eject a floppy disc. Disc has to be teased out of the
artistic mouldings using long nose pliers.

In my experience, this can usually be fixed by unscrewing and then *carefully*
re-mounting the drive bracket into a *working* position prior to tightening
the screws. The problem seems to be that tolerances are really sloppy on a
lot of these cases, so while there is *some* screw position that makes
everything align, it's almost never obtained when someone just arbitrarily
screws everything together.

Interestingly, companies like Dell seem to do a good job at proving that case
design *can* be both mechanically robust and inexpensive -- it just requires
(apparently) above-average designers.

 

[Martin Plourde]

Hi,

I am a seller of pre-owned test equipment and to me, the choice is
obvious...............Xantrex !!!!!!!!!!!!!!!

Martin

"CC" <somewhere@overthe.rainbow.net> a écrit dans le message de news:
eagn7p02fb8@news1.newsguy.com...

Hi:

I returned my Protek 3044T power supply, which I didn't like because it's
impossible to set low current limits precisely. Partly due to the 0.01A
resolution meters, but also the knobs are linear. And at low currents
there was a large 2x discrepancy between the setpoint and actual limit
(actual lower than limit). Finally, the one I received at home buzzed
when I turned it on because a transformer cover was not secure and not
easy to fix.

I'm also likely to dump my Protek 1805 power supply on Ebay. Anybody want
it for 60% of the $193.80 purchase price (not incl. shipping)?

At least Xantrex puts logarithmic current control pots in their "knob"
type power supplies.

But also, I found that the Protek supplies get screamin' hot even at
currents of about half the rating. This bugs me. I don't like designs
that push the limits of component temperature.

I regret trying to save money with the Protek supplies. More than half of
the time I try saving money I wind up sending junk back, wasting a bunch
of time&shipping charges. Almost never do I regret buying something with
a hefty price tag but clearly superior quality.

I'm now inclining toward programmable supplies only, because I'm getting
hooked on the digital settability after getting an Agilent E3631A and a
Xantrex XDL35-5 at work. Agilent user interfaces leave much to be
desired, though.

The Xantrex is one precise power supply! And the user interface is very
good as well. Monday I should give it a heavy load test to see how the
heat is.

What I need is a logic level supply that can do at least 18V 5A, and a
dual supply that can do at least 30V 2A.

I was considering replacing the Protek 3044T with a Xantrex XPL30-2D
"knob" supply. This would be adequate for +/- rails for linear type
circuit experimenting, and their log pots should avoid the low current
settability problem of many knob-set supplies.

http://www.testequity.com/products/1147/

Then splurge on the $815 Xantrex XDL35-5 for the logic supply. The thing
that bugs me is that the Xantrex doesn't have a computer interface unless
I pay $1025 for the XDL35-5P model. Ouch!

http://www.testequity.com/products/1148/

For that money, it makes me consider instead to look at the Instek
PSM-3004 or PSM-6003 which have standard interfaces for more versatility
in terms of voltage and current range. But then again, I have more use
for the Xantrex's 0.1mA lower end precision.

http://www.testequity.com/products/1310/


So many choices; Ugh!



--
_____________________
Christopher R. Carlen
crobc@bogus-remove-me.sbcglobal.net
SuSE 9.1 Linux 2.6.5

 

[Chris Carlen]

Martin Plourde wrote:

Hi,

I am a seller of pre-owned test equipment and to me, the choice is
obvious...............Xantrex !!!!!!!!!!!!!!!

Martin

I'm definitely not going to go with Protek again. But can you say
anything about Instek? The PSM series dual range supplies look really
good on paper, except for being massive.


--
Good day!

________________________________________
Christopher R. Carlen
Principal Laser&Electronics Technologist
Sandia National Laboratories CA USA
crcarleRemoveThis@BOGUSsandia.gov
NOTE, delete texts: "RemoveThis" and
"BOGUS" from email address to reply.

 

[jasen]

On 2006-07-30, John Jardine. <john@jjdesigns.fsnet.co.uk> wrote:

Last year, mail ordered a standard, mini tower, PC case. Front panel a
swirl of artistic, post-modern, sculpted mouldings.
Can't though f*****g eject a floppy disc. Disc has to be teased out of the
artistic mouldings using long nose pliers.

agree it's a stupid design. hit the eject button harder (works sometimes)
or consider replacing the drive, I get 3-4cm here, or just rip that stupidf
plastc bit off, it serves no useful purpose.

The PC and programming world seemingly survives with secondrate as a norm.
Yet a powertool company (as a real world example) would only last months if
a similar attitude to users needs was adopted.

Rhino's been making makita knock-offs for a few years now...

Bye.
Jasen