Atco Possum Electronic tranny redux

T

Trevor Wilson

Guest
I recently installed a bunch of these in my home and was pleased with the
much lower heat production, compared to the old iron trannies. I was
prompted to replace them, whilst doing some work in the ceiling and, after
touching one of the old trannies, was horrified at how hot they got. Anyway,
here's my measurements on the new vs. the old trannies (it also explains why
the lights seen somewhat brighter than the old):

All measurments performed at 240 VAC.

Old tranny:
Output Voltage: 11.4 VAC
Power consumption: 64.7 watts

New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


A good thing. Dunno about the lifespan of the lamps, given the higher input
Volts though.

Some more nice things about the Crompton kits, which use the Possum
trannies:

Silicon leads for the lamps.
A nice gimbal mount
The lamps have a glass cover.
I like the cord clamping on the Possum trannies. A clever design.

The biggest win, however, has been the replacement of the 120 Watt lamps in
the bathrooms, with some Phillips 23 Watt compact fluoros (the ones with the
curly tubes). VERY impressive light output, with almost identical spectra to
the old incandescent. Highly reccommended. 8 Bucks each from Bunnings.


--
Trevor Wilson
www.rageaudio.com.au




--
Posted via a free Usenet account from http://www.teranews.com
 
"Trevor Wilson" <trevor@SPAMBLOCKrageaudio.com.au> wrote in message
news:4484b4d0$0$26851$88260bb3@free.teranews.com...
I recently installed a bunch of these in my home and was pleased with the
much lower heat production, compared to the old iron trannies. I was
prompted to replace them, whilst doing some work in the ceiling and, after
touching one of the old trannies, was horrified at how hot they got.
Anyway, here's my measurements on the new vs. the old trannies (it also
explains why the lights seen somewhat brighter than the old):

All measurments performed at 240 VAC.

Old tranny:
Output Voltage: 11.4 VAC
Power consumption: 64.7 watts

New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


A good thing. Dunno about the lifespan of the lamps, given the higher
input Volts though.
Click to expand...
Ok, take out a CRO and have a look at the output voltage of the Possum.
Fairly ugly compared to the nice sinusoidal waveform of the old iron cores.
The voltage you measured would not be accurate, as I think from memory, the
rated output voltage of most ET's is about 11.6V thereabouts. If you have a
higher voltage you will have a shorter lifespan on those dichroics.

Of course if you have them dimmed all the time then that's a different
matter.

Another thing. A device needs to reach a temperature of 200 deg C. to start
a fire when placed next to timber. I think, again from memory, that 60 deg
C. becomes too hot to touch. This could, I assume, give one false reasoning.

Cheers.
 
"Trevor Wilson"

New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts
Click to expand...
** How did you measure this?

The output of a " Possum" is a 100Hz, amplitude modulated, 45kHz squarish
wave.

Harmonics out to 500 kHz.

Evil.





......... Phil
 
On Tue, 06 Jun 2006 10:13:25 GMT, "me" <hus@nospam.com> wrote:

"Trevor Wilson" <trevor@SPAMBLOCKrageaudio.com.au> wrote in message
news:4484b4d0$0$26851$88260bb3@free.teranews.com...
I recently installed a bunch of these in my home and was pleased with the
much lower heat production, compared to the old iron trannies. I was
prompted to replace them, whilst doing some work in the ceiling and, after
touching one of the old trannies, was horrified at how hot they got.
Anyway, here's my measurements on the new vs. the old trannies (it also
explains why the lights seen somewhat brighter than the old):

All measurments performed at 240 VAC.

Old tranny:
Output Voltage: 11.4 VAC
Power consumption: 64.7 watts

New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


A good thing. Dunno about the lifespan of the lamps, given the higher
input Volts though.


Ok, take out a CRO and have a look at the output voltage of the Possum.
Fairly ugly compared to the nice sinusoidal waveform of the old iron cores.
Click to expand...
I need a nice clean sine wave for light bulbs too.

The voltage you measured would not be accurate, as I think from memory, the
rated output voltage of most ET's is about 11.6V thereabouts. If you have a
higher voltage you will have a shorter lifespan on those dichroics.
Of course if you have them dimmed all the time then that's a different
matter.

Another thing. A device needs to reach a temperature of 200 deg C. to start
a fire when placed next to timber. I think, again from memory, that 60 deg
C. becomes too hot to touch. This could, I assume, give one false reasoning.

Cheers.
Click to expand...
 
"Phil Allison" <philallison@tpg.com.au> wrote in message
news:4el3alF1f1rj1U1@individual.net...
"Trevor Wilson"

New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


** How did you measure this?
Click to expand...
**A 'True RMS' meter.

The output of a " Possum" is a 100Hz, amplitude modulated, 45kHz squarish
wave.

Harmonics out to 500 kHz.

Evil.
Click to expand...
**Yup. Very efficient though.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com
 
"Trevor Wilson"

New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


** How did you measure this?

**A 'True RMS' meter.
Click to expand...

** LOL.

Like they are all the same ....





.......... Phil
 
Phil Allison wrote:
"Trevor Wilson"


New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


** How did you measure this?

**A 'True RMS' meter.




** LOL.

Like they are all the same ....


......... Phil
Click to expand...
They are if you use a real RMS meter, eg HP3400A thermal RMS voltmeter
or a Fluke 8920 (IIRC)

Cheers
Terry
 
"Terry Given"
New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


** How did you measure this?

**A 'True RMS' meter.




** LOL.

Like they are all the same ....


......... Phil

They are if you use a real RMS meter, eg HP3400A thermal RMS voltmeter or
a Fluke 8920 (IIRC)
Click to expand...

* A "True RMS" meter can be anything from a moving iron type up.

YOU have NO idea what TW used - so SHUT THE FUCK UP !

you ASININE SHEEP FUCKER






........ Phil
 
Phil Allison wrote:
"Terry Given"

New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


** How did you measure this?

**A 'True RMS' meter.




** LOL.

Like they are all the same ....


......... Phil

They are if you use a real RMS meter, eg HP3400A thermal RMS voltmeter or
a Fluke 8920 (IIRC)




* A "True RMS" meter can be anything from a moving iron type up.

YOU have NO idea what TW used - so SHUT THE FUCK UP !

you ASININE SHEEP FUCKER


....... Phil
Click to expand...
Lovely stuff Phil, good to see you are still angry at the world. You do
realise its bad for your health dont you?

And yes, many meters do call themselves "true RMS" when in actual fact
they are not. And almost all of them have significant bandwidth constraints.

But the HP3400 and Fluke 8920 really are true broadband RMS thermal
voltmeters, and will give an accurate RMS reading from LF to MHz.

Cheers
Terry
 
"Terry Given"

New tranny:
Output Voltage: 12.8 Volts
Power consumption: 56.4 Watts


** How did you measure this?

**A 'True RMS' meter.




** LOL.

Like they are all the same ....


......... Phil

They are if you use a real RMS meter, eg HP3400A thermal RMS voltmeter or
a Fluke 8920 (IIRC)




* A "True RMS" meter can be anything from a moving iron type up.

YOU have NO idea what TW used - so SHUT THE FUCK UP !

you ASININE SHEEP FUCKER




Lovely stuff Phil, good to see you are still angry at the world. You do
realise its bad for your health dont you?

And yes, many meters do call themselves "true RMS" when in actual fact
they are not. And almost all of them have significant bandwidth
constraints.

But the HP3400 and Fluke 8920 really are true broadband RMS thermal
voltmeters, and will give an accurate RMS reading from LF to MHz.
Click to expand...

* A "True RMS" meter can be anything from a moving iron type up.

YOU have NO idea what TW used - so SHUT THE FUCK UP !


you ASININE SHEEP FUCKER







........ Phil
 
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