Electronic Load

[Joe]

Does anyone know of a supplier in Australia for "reasonably priced"
adjustable electronic loads for testing DC power power supplies up to 3
amps?

I can't even find any suitable circuits to make them (I need a few of them).

Silicon Chip described one recently but I can't find a supplier of a kit for
it. DSE, Jaycar and Altronics don't mention it on their websites. I wasn't
too keen on this particular design anyway because it required an external
power supply to run it.

Thanks for any help.

J.

 

[mikeqld]

I am not a techie but wouldn't a cheap amp meter, light bulb and a variable
pot in series do the trick. All we ever used.

"Joe" <joe.m@mackay.nu> wrote in message
news:3f705d43$1@news.comindico.com.au...

Does anyone know of a supplier in Australia for "reasonably priced"
adjustable electronic loads for testing DC power power supplies up to 3
amps?

I can't even find any suitable circuits to make them (I need a few of
them).

Silicon Chip described one recently but I can't find a supplier of a kit
for
it. DSE, Jaycar and Altronics don't mention it on their websites. I
wasn't
too keen on this particular design anyway because it required an external
power supply to run it.

Thanks for any help.

J.

 

[Joe]

"mikeqld" <Only@Reply.On.News.Group.com> wrote in message
news:gk1cb.119451$bo1.13138@news-server.bigpond.net.au...

I am not a techie but wouldn't a cheap amp meter, light bulb and a
variable
pot in series do the trick. All we ever used.

No, we need something more accurate than that. We're actually testing
battery powered, 12 volt power supplies and with your arrangement, the load
will vary as the battery discharges. I want to be able to set it say 1 amp
and have it stay discharging accurately at 1 amp even as the voltage falls.

I've searched Google for suppliers of commercial units in Australia, as well
as circuit and not much comes up. I'm very surprised that I can't even find
a supplier of the Silicon Chip kit.

J.

"Joe" <joe.m@mackay.nu> wrote in message
news:3f705d43$1@news.comindico.com.au...
Does anyone know of a supplier in Australia for "reasonably priced"
adjustable electronic loads for testing DC power power supplies up to 3
amps?

I can't even find any suitable circuits to make them (I need a few of
them).

Silicon Chip described one recently but I can't find a supplier of a kit
for
it. DSE, Jaycar and Altronics don't mention it on their websites. I
wasn't
too keen on this particular design anyway because it required an
external
power supply to run it.

Thanks for any help.

J.

 

[John Crighton]

On Tue, 23 Sep 2003 14:48:43 GMT, "Joe" <joe.m@mackay.nu> wrote:

Does anyone know of a supplier in Australia for "reasonably priced"
adjustable electronic loads for testing DC power power supplies up to 3
amps?

I can't even find any suitable circuits to make them (I need a few of them).

Silicon Chip described one recently but I can't find a supplier of a kit for
it. DSE, Jaycar and Altronics don't mention it on their websites. I wasn't
too keen on this particular design anyway because it required an external
power supply to run it.

Thanks for any help.

J.

Hello Joe,
have a look here
http://www.webx.dk/oz2cpu/radios/dc-load.htm
you might get a few ideas from this circuit to build
what you want.
Regards,
John Crighton
Hornsby

 

[Ross Herbert]

Joe wrote:

Does anyone know of a supplier in Australia for "reasonably priced"
adjustable electronic loads for testing DC power power supplies up to 3
amps?

I can't even find any suitable circuits to make them (I need a few of them).

Silicon Chip described one recently but I can't find a supplier of a kit for
it. DSE, Jaycar and Altronics don't mention it on their websites. I wasn't
too keen on this particular design anyway because it required an external
power supply to run it.

Thanks for any help.

J.


I know of only 1 manufacturer of electronic loads... Kikusui

http://www.kikusui.co.jp/en/catalog/selection_EL_e.html

Emona Instruments http://www.emona.com.au/ are distributors for Kikusui
and sometimes have demo items for sale, but I must add they aren't
cheap. The last time I saw anything offered by them the going price was
around $1300 for a secondhand PLZ72W model.

Hinco Instruments http://www.hinco.com.au/ in WA are Kikusui
distributors so you might contact them to see if they can help.

Ross H

 

Joe wrote:

"mikeqld" <Only@Reply.On.News.Group.com> wrote in message
news:gk1cb.119451$bo1.13138@news-server.bigpond.net.au...
I am not a techie but wouldn't a cheap amp meter, light bulb and a
variable
pot in series do the trick. All we ever used.

No, we need something more accurate than that. We're actually testing
battery powered, 12 volt power supplies and with your arrangement, the load
will vary as the battery discharges. I want to be able to set it say 1 amp
and have it stay discharging accurately at 1 amp even as the voltage falls.

I've searched Google for suppliers of commercial units in Australia, as well
as circuit and not much comes up. I'm very surprised that I can't even find
a supplier of the Silicon Chip kit.

J.

1. Give Tech Rentals a call to hire one. They have offices in each state.
You can hire weekly or monthly. You can ascertain the respective qualities
of different loads, and make a choice to purchase based upon your experiences
with each.

2. A simple brute force electronic load could be designed and constructed
using a large wattage 1 ohm resistor, 1 or 2 2N3055 transistors, a microcontroller
with a a/d converter, a d/a converter and a couple of buffers. A serial port
would be useful for communicating with the micro, and a lcd may be useful.
Place the 1 ohm resistor on the collector, drive the base of the 2N3055(s)
with a current amplifier buffer, drive the buffer with the d/a converter,
monitor the voltage across the 1 ohm resistor with the a/d converter in
the microcontroller. You should be able to program the controller to
change the base current of the 2N3055(s), thereby changing the collector
current to whatever you want (within reason), according to any voltage change
across the resistor, thus maintaining the current drawn from the battery.

--

David

 

[daniel - macservice]

Do your shopping, I'm sure we have a couple around in the warehouse, we do
use one ourselves in our repair lab for testing power supply's, seriously
consider making one yourself if budget is a problem cause the large power
ones can get expensive,
but if you in the market for something industrial don't forget to get a
quote from us, macservice 03 95580004, ask to speak to sales, tell them what
your after and what you've been quoted I'm sure we will try to get you a
good deal.

*apologies if this is too much spam......

"Ross Herbert" <rherber1@bigpond.net.au> wrote in message
news:rl4cb.119772$bo1.87247@news-server.bigpond.net.au...

Joe wrote:
Does anyone know of a supplier in Australia for "reasonably priced"
adjustable electronic loads for testing DC power power supplies up to 3
amps?

I can't even find any suitable circuits to make them (I need a few of
them).

Silicon Chip described one recently but I can't find a supplier of a kit
for
it. DSE, Jaycar and Altronics don't mention it on their websites. I
wasn't
too keen on this particular design anyway because it required an
external
power supply to run it.

Thanks for any help.

J.


I know of only 1 manufacturer of electronic loads... Kikusui
http://www.kikusui.co.jp/en/catalog/selection_EL_e.html

Emona Instruments http://www.emona.com.au/ are distributors for Kikusui
and sometimes have demo items for sale, but I must add they aren't
cheap. The last time I saw anything offered by them the going price was
around $1300 for a secondhand PLZ72W model.

Hinco Instruments http://www.hinco.com.au/ in WA are Kikusui
distributors so you might contact them to see if they can help.

Ross H

 

[John Crighton]

On Wed, 24 Sep 2003 20:29:03 +1000, "daniel - macservice"
<daniel@macservice.com.au> wrote:

*apologies if this is too much spam......

Hello Daniel,
No need to apologise, you have not spammed at all.
We can all use a bit of help. I have been looking
for a few meters of nichrome resistance wire about
the thickness of coathanger wire. Any Ideas
where to get some?
Regards,
John Crighton
Hornsby

 

[Terry Hulme]

Joe, am I right in assuming that you aren't using batteries to drive a
switching power supply as I would have thought that a smps/invertor
would supply a constant output voltage even though the input battery
voltage was dropping, until a point is reached at which the smps would
cease switching when no longer able to supply the required reference
voltage?
regards Terry

On Tue, 23 Sep 2003 20:30:45 GMT, "Joe" <joe.m@mackay.nu> wrote:

"mikeqld" <Only@Reply.On.News.Group.com> wrote in message
news:gk1cb.119451$bo1.13138@news-server.bigpond.net.au...
I am not a techie but wouldn't a cheap amp meter, light bulb and a
variable
pot in series do the trick. All we ever used.

No, we need something more accurate than that. We're actually testing
battery powered, 12 volt power supplies and with your arrangement, the load
will vary as the battery discharges. I want to be able to set it say 1 amp
and have it stay discharging accurately at 1 amp even as the voltage falls.

I've searched Google for suppliers of commercial units in Australia, as well
as circuit and not much comes up. I'm very surprised that I can't even find
a supplier of the Silicon Chip kit.

J.

"Joe" <joe.m@mackay.nu> wrote in message
news:3f705d43$1@news.comindico.com.au...
Does anyone know of a supplier in Australia for "reasonably priced"
adjustable electronic loads for testing DC power power supplies up to 3
amps?

I can't even find any suitable circuits to make them (I need a few of
them).

Silicon Chip described one recently but I can't find a supplier of a kit
for
it. DSE, Jaycar and Altronics don't mention it on their websites. I
wasn't
too keen on this particular design anyway because it required an
external
power supply to run it.

Thanks for any help.

J.

 

[Richard Freeman]

<dmmilne@ozemail.com.au> wrote in message
news:3F70DF75.D4B278B0@ozemail.com.au...

Joe wrote:

"mikeqld" <Only@Reply.On.News.Group.com> wrote in message
news:gk1cb.119451$bo1.13138@news-server.bigpond.net.au...
I am not a techie but wouldn't a cheap amp meter, light bulb and a
variable
pot in series do the trick. All we ever used.

No, we need something more accurate than that. We're actually testing
battery powered, 12 volt power supplies and with your arrangement, the
load
will vary as the battery discharges. I want to be able to set it say 1
amp
and have it stay discharging accurately at 1 amp even as the voltage
falls.

I've searched Google for suppliers of commercial units in Australia, as
well
as circuit and not much comes up. I'm very surprised that I can't even
find
a supplier of the Silicon Chip kit.

J.

1. Give Tech Rentals a call to hire one. They have offices in each state.
You can hire weekly or monthly. You can ascertain the respective qualities
of different loads, and make a choice to purchase based upon your
experiences
with each.

Good Idea

2. A simple brute force electronic load could be designed and constructed
using a large wattage 1 ohm resistor, 1 or 2 2N3055 transistors,

Yep include say a pot and an Op amp - and a ammeter to set the current
fairly straightforward

a microcontroller
with a a/d converter, a d/a converter and a couple of buffers. A serial
port
would be useful for communicating with the micro, and a lcd may be useful.

depends on how flash you want it certainly development time for a simple
analog solution should not take to long

Place the 1 ohm resistor on the collector, drive the base of the 2N3055(s)
with a current amplifier buffer, drive the buffer with the d/a converter,
monitor the voltage across the 1 ohm resistor with the a/d converter in
the microcontroller.

why not monitor / compare the voltage with an op amp? use the DAC to set the
current - if you need it this flash a pot should do the trick nicely if not.

You should be able to program the controller to
change the base current of the 2N3055(s), thereby changing the collector
current to whatever you want (within reason), according to any voltage
change
across the resistor, thus maintaining the current drawn from the battery.

why does everything nowadays seem to automatically need a micro ? even it
seems the simplest of ideas I reckon stick with an analog solution using an
op amp, a pot and an ammeter.

Regards
Richard Freeman

 

[daniel - macservice]

Wow that quite thick stuff you want, I know I have the smaller gauge wire,
usually get about $10 a roll, I dont think i've seen anything thicker....
sorry ;-/

-Dan


"John Crighton" <john_c@tpg.com.au> wrote in message
news:3f718a07.30934780@News.CIS.DFN.DE...

On Wed, 24 Sep 2003 20:29:03 +1000, "daniel - macservice"
daniel@macservice.com.au> wrote:

*apologies if this is too much spam......

Hello Daniel,
No need to apologise, you have not spammed at all.
We can all use a bit of help. I have been looking
for a few meters of nichrome resistance wire about
the thickness of coathanger wire. Any Ideas
where to get some?
Regards,
John Crighton
Hornsby

 

Richard Freeman wrote:

dmmilne@ozemail.com.au> wrote in message
news:3F70DF75.D4B278B0@ozemail.com.au...
Joe wrote:

"mikeqld" <Only@Reply.On.News.Group.com> wrote in message
news:gk1cb.119451$bo1.13138@news-server.bigpond.net.au...
I am not a techie but wouldn't a cheap amp meter, light bulb and a
variable
pot in series do the trick. All we ever used.

No, we need something more accurate than that. We're actually testing
battery powered, 12 volt power supplies and with your arrangement, the
load
will vary as the battery discharges. I want to be able to set it say 1
amp
and have it stay discharging accurately at 1 amp even as the voltage
falls.

why does everything nowadays seem to automatically need a micro ? even it
seems the simplest of ideas I reckon stick with an analog solution using an
op amp, a pot and an ammeter.

Regards
Richard Freeman

Nothing wrong with it at all, but I feel it's just a small improvement to what the op
has already implemented. Someone already posted a link to a load that looks like what
you are suggesting. My reasons are that the op expressed a wish to set the load
such that the current was a constant 1 amp, and since batteries have a non-linear
discharge curve, that required an automatic monitoring system. Of course the opamp
could be implemented in a feedback circuit which would enable this to be achieved,
but something that monitors the voltage and current, and can either store that data
or send it to a file is more attractive, well to me at least.

--

Regards
David