9v DC from 3 phase power line

Guest
I have a machine with 1kW, 3 phase motor.
I also have a sensor board measuring temperature, humidity and rotation
speed. This board operates with 9v, 100mA DC.
How can I obtain 9v from the 3 phase power line?
Can I use any two line of the 3 phase power line to connect an ordinary 240v
to 12 v transformer?
 
Johnietta wrote:
I have a machine with 1kW, 3 phase motor.
I also have a sensor board measuring temperature, humidity and rotation
speed. This board operates with 9v, 100mA DC.
How can I obtain 9v from the 3 phase power line?
Can I use any two line of the 3 phase power line to connect an ordinary 240v
to 12 v transformer?
Click to expand...
Yes, if the 3 phase power has 240 volts line to line.

--
John Popelish
 
<Johnietta> wrote in message
news:41654ed0$0$20581$afc38c87@news.optusnet.com.au...
I have a machine with 1kW, 3 phase motor.
I also have a sensor board measuring temperature, humidity and
rotation
speed. This board operates with 9v, 100mA DC.
How can I obtain 9v from the 3 phase power line?
Can I use any two line of the 3 phase power line to connect an
ordinary 240v
to 12 v transformer?
Click to expand...
The above seems to originate in Australia where there is almost
universally 3phase Y connected 230/400 volt supplies.
In a motor situation there may not be a handy neautral but general
purpose power is always 230 volts phase to neautral and the only
trnsformers (Wall Warts) readly avaiable are 230 to whatever.
Of course it may be expedient to buy a special transformer with a 400
volt primary if there is no neautral at the actual location this 9 volts
is required.
--
John G

Wot's Your Real Problem?
 
On Fri, 8 Oct 2004 00:12:29 +1000, <Johnietta> wrote:

|I have a machine with 1kW, 3 phase motor.
|I also have a sensor board measuring temperature, humidity and rotation
|speed. This board operates with 9v, 100mA DC.
|How can I obtain 9v from the 3 phase power line?
|Can I use any two line of the 3 phase power line to connect an ordinary 240v
|to 12 v transformer?
|
Listen only to swanny.....

The fact is that if you measure between ANY 2 PHASES you will read 415
V nominal. If you measure between ANY ONE PHASE and NEUTRAL you will
read 240V nominal. Since this is what you require for a readily
available wall-wart transformer then that's how you obtain the primary
input voltage for the wall-wart.
 
<Johnietta> wrote in message
news:41654ed0$0$20581$afc38c87@news.optusnet.com.au...
I have a machine with 1kW, 3 phase motor.
I also have a sensor board measuring temperature, humidity and rotation
speed. This board operates with 9v, 100mA DC.
How can I obtain 9v from the 3 phase power line?
Can I use any two line of the 3 phase power line to connect an ordinary
240v to 12 v transformer?
Click to expand...
If you have to ask that, you shouldnt be doing any such thing!
 
bust out one of the phases and neutral. you can run this to the
appropriate transformer with some filter caps in front of and behind a
7809 voltage regulator ic.
any of the phases to neutral will be about 120vac but if you go across 2
phases then the voltage goes up to about 208vac or so
be careful

Howard Latham wrote:

Johnietta> wrote in message
news:41654ed0$0$20581$afc38c87@news.optusnet.com.au...

I have a machine with 1kW, 3 phase motor.
I also have a sensor board measuring temperature, humidity and rotation
speed. This board operates with 9v, 100mA DC.
How can I obtain 9v from the 3 phase power line?
Can I use any two line of the 3 phase power line to connect an ordinary
240v to 12 v transformer?


If you have to ask that, you shouldnt be doing any such thing!
Click to expand...
 
oops....i'm thinking you are in america but i'm thinking now australia?
my response would work in america but i'm not sure what the voltages are
in australia.
be careful

carl wrote:

bust out one of the phases and neutral. you can run this to the
appropriate transformer with some filter caps in front of and behind a
7809 voltage regulator ic.
any of the phases to neutral will be about 120vac but if you go across 2
phases then the voltage goes up to about 208vac or so
be careful

Howard Latham wrote:

Johnietta> wrote in message
news:41654ed0$0$20581$afc38c87@news.optusnet.com.au...

I have a machine with 1kW, 3 phase motor.
I also have a sensor board measuring temperature, humidity and
rotation speed. This board operates with 9v, 100mA DC.
How can I obtain 9v from the 3 phase power line?
Can I use any two line of the 3 phase power line to connect an
ordinary 240v to 12 v transformer?



If you have to ask that, you shouldnt be doing any such thing!
Click to expand...
 
"carl" <nospam@charter.net> wrote in message
news:10p8hf76gg7d78@corp.supernews.com...
a separate supply would be better, i agree, but with the exception of
the confused voltages, i gave him what he was asking for. i'm not here
to tell him what he's asking for.

Rheilly Phoull wrote:

"carl" <nospam@charter.net> wrote in message
news:10p5karcm40qu57@corp.supernews.com...

oops....i'm thinking you are in america but i'm thinking now australia?
my response would work in america but i'm not sure what the voltages are
in australia.
be careful

carl wrote:


bust out one of the phases and neutral. you can run this to the
appropriate transformer with some filter caps in front of and behind a
7809 voltage regulator ic.
any of the phases to neutral will be about 120vac but if you go across
2
phases then the voltage goes up to about 208vac or so
be careful

Howard Latham wrote:


Johnietta> wrote in message
news:41654ed0$0$20581$afc38c87@news.optusnet.com.au...


I have a machine with 1kW, 3 phase motor.
I also have a sensor board measuring temperature, humidity and
rotation speed. This board operates with 9v, 100mA DC.
How can I obtain 9v from the 3 phase power line?
Can I use any two line of the 3 phase power line to connect an
ordinary 240v to 12 v transformer?



If you have to ask that, you shouldnt be doing any such thing!




Whilst no doubt you could make it work in that manner (Aus supply being
415v
phase to phase) it would not be a good method. Far better to have a
seperate
supply for the monitoring eqt. I am assuming that the motor runs off an
outlet ??
If it has a control cabinet or motor starter cubicle then mounting the
tranny with a fuse in the supply line would be the best approach.

--
Regards ........... Rheilly Phoull
Click to expand...
Oh OK now I understand.


--
Regards ........... Rheilly Phoull
 
a separate supply would be better, i agree, but with the exception of
the confused voltages, i gave him what he was asking for. i'm not here
to tell him what he's asking for.

Rheilly Phoull wrote:

"carl" <nospam@charter.net> wrote in message
news:10p5karcm40qu57@corp.supernews.com...

oops....i'm thinking you are in america but i'm thinking now australia?
my response would work in america but i'm not sure what the voltages are
in australia.
be careful

carl wrote:


bust out one of the phases and neutral. you can run this to the
appropriate transformer with some filter caps in front of and behind a
7809 voltage regulator ic.
any of the phases to neutral will be about 120vac but if you go across 2
phases then the voltage goes up to about 208vac or so
be careful

Howard Latham wrote:


Johnietta> wrote in message
news:41654ed0$0$20581$afc38c87@news.optusnet.com.au...


I have a machine with 1kW, 3 phase motor.
I also have a sensor board measuring temperature, humidity and
rotation speed. This board operates with 9v, 100mA DC.
How can I obtain 9v from the 3 phase power line?
Can I use any two line of the 3 phase power line to connect an
ordinary 240v to 12 v transformer?



If you have to ask that, you shouldnt be doing any such thing!




Whilst no doubt you could make it work in that manner (Aus supply being 415v
phase to phase) it would not be a good method. Far better to have a seperate
supply for the monitoring eqt. I am assuming that the motor runs off an
outlet ??
If it has a control cabinet or motor starter cubicle then mounting the
tranny with a fuse in the supply line would be the best approach.

--
Regards ........... Rheilly Phoull
Click to expand...
 
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