9v DC from 3 phase power line

G

Guest

Jan 1, 1970
0
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?

J

John Popelish

Jan 1, 1970
0
Johnietta said:
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?

Yes, if the 3 phase power has 240 volts line to line.

E

Externet

Jan 1, 1970
0
Yes, you can use an adapter with the same primary tension as two of
the phases tension. Measure voltage across 2 phases first.
Miguel

J

John G

Jan 1, 1970
0
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?

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.

J

James

Jan 1, 1970
0
John G said:
<Johnietta> wrote in message Snipto 12 v transformer?

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.

Thats the usual way here in aus. Transformers with 415 volt primaries
aren't too hard to find here, its very common in industrial control.
An industrial supply shop should have the transformer you want. If you
try and connect a transformer designed for 240 onto 415 volts it will
saturate and you will quickly burn it out. If a neutral is present
just connect it between an active and neutral. Be careful of colour
codes too, machines seem to use a wide variety of colours for various
things - black isn't necessarily neutral.

Check the voltage first

cheers

R

Ross Herbert

Jan 1, 1970
0
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.

H

Howard Latham

Jan 1, 1970
0
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!

C

carl

Jan 1, 1970
0
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

C

carl

Jan 1, 1970
0
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

R

Rheilly Phoull

Jan 1, 1970
0
carl said:
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

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.

C

carl

Jan 1, 1970
0
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.

R

Rheilly Phoull

Jan 1, 1970
0
carl said:
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.

Oh OK now I understand.

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