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how to reduce the mains voltage...

M

~misfit~

Guest
On 12/08/2020 9:38 pm, default wrote:
On Wed, 12 Aug 2020 14:35:18 +1200, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

On 12/08/2020 9:19 am, default wrote:
On Tue, 11 Aug 2020 22:01:39 +1200, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

On 14/07/2020 8:08 am, etpm@whidbey.com wrote:
On Mon, 13 Jul 2020 11:31:30 -0400, default <default@defaulter.net
wrote:

I have an older window air conditioner that I\'d like to hang on to for
a few more years. The name plate says it is 220 VAC and since the
power company went through and upgraded the distribution network and
replaced HT and transformers my service which had been running 210-220
volts is now a steady 250 volts and my bill is up ~15%.

The increased consumption is tied to how much I run the AC and since
the upgrade I\'ve already had to replace both the compressor and fan
motor run caps. The compressor one died a quiet death, and the fan
cap melted and smoked. The compressor cap went out the week they
changed the transformer and the fan cap about a month later. I put in
higher voltage ones and the AC is back on line.

I was wondering if putting in 240 VAC to 24VAC center tapped, 10 amp
power transformer, wired to buck the voltage makes any sense?
Where I live we get 250 volts pretty steadily. In my shop are
several CNC machines, one of which cannot easily tolerate the 250
volts. So I use two buck/boost xmfrs wired in a particular buck
configuration to lower the 3 phase voltage going to that one machine.
Since doing so the machine has not once alarmede out due to over
voltage.
I also wired up a little 120 to 12 volt xmfr in buck configuration
to lower the 125 volts from the outlet to the 110 volts needed for a
tube amp.
There are directions online on how to select the proper sized xmfr
for the load it will be seeing and how to wire the thing in buck
configuration.
Eric


Eric could you please give me directions to on-line info? I\'m looking at dropping the voltage to a
transformer so that I get lower secondaries out of it inexpensively. Single phase. My Google Fu
isn\'t very strong on this one. I remember Big Clive doing similar in one of his videos a while back
but have been unable to find that again.

Cheers,

See:
https://sound-au.com/articles/buck-xfmr.htm#s30

Explains \"the proper way\" to wire a buck boost. Both of the methods
shown work, one is just slightly more efficient.

My AC uses 7-8 amps so my 24 VCT transformer is rated at 10 amps or
240 VA.

Cheers. I have a 300 VA 50v output toriod in an amplifier that I want to re-use in an amp that
needs 40 - 45v AC. I\'ll get to calculating...

Toroids are great for that if they aren\'t potted. I used a pair of
large toroids from a surplus store for an audio power amp. The
voltage was borderline for the transistors I was using, so I wound a
few turns on the core and phased it to subtract voltage. I think it
was two turns of wire was ~.8 volts, and I wanted to go down 5 volts.
Interesting thanks, I\'ll consider that too. It\'s well wrapped but I might be able to work something
out. It\'s a project I haven\'t touched for a wee while now.

(I was also considering doing a small top-winding with insulated wire to get a low voltage out of
it for the speaker protection circuit I\'d like to fit rather than buying and including a second
transformer in the chassis.)
--
Shaun.

\"Humans will have advanced a long, long way when religious belief has a cozy little classification
in the DSM\"
David Melville

This is not an email and hasn\'t been checked for viruses by any half-arsed self-promoting software.
 
D

default

Guest
On Mon, 17 Aug 2020 17:31:43 +1200, ~misfit~
<shaun.at.pukekohe@gmail.com> wrote:

On 12/08/2020 9:38 pm, default wrote:
On Wed, 12 Aug 2020 14:35:18 +1200, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

On 12/08/2020 9:19 am, default wrote:
On Tue, 11 Aug 2020 22:01:39 +1200, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

On 14/07/2020 8:08 am, etpm@whidbey.com wrote:
On Mon, 13 Jul 2020 11:31:30 -0400, default <default@defaulter.net
wrote:

I have an older window air conditioner that I\'d like to hang on to for
a few more years. The name plate says it is 220 VAC and since the
power company went through and upgraded the distribution network and
replaced HT and transformers my service which had been running 210-220
volts is now a steady 250 volts and my bill is up ~15%.

The increased consumption is tied to how much I run the AC and since
the upgrade I\'ve already had to replace both the compressor and fan
motor run caps. The compressor one died a quiet death, and the fan
cap melted and smoked. The compressor cap went out the week they
changed the transformer and the fan cap about a month later. I put in
higher voltage ones and the AC is back on line.

I was wondering if putting in 240 VAC to 24VAC center tapped, 10 amp
power transformer, wired to buck the voltage makes any sense?
Where I live we get 250 volts pretty steadily. In my shop are
several CNC machines, one of which cannot easily tolerate the 250
volts. So I use two buck/boost xmfrs wired in a particular buck
configuration to lower the 3 phase voltage going to that one machine.
Since doing so the machine has not once alarmede out due to over
voltage.
I also wired up a little 120 to 12 volt xmfr in buck configuration
to lower the 125 volts from the outlet to the 110 volts needed for a
tube amp.
There are directions online on how to select the proper sized xmfr
for the load it will be seeing and how to wire the thing in buck
configuration.
Eric


Eric could you please give me directions to on-line info? I\'m looking at dropping the voltage to a
transformer so that I get lower secondaries out of it inexpensively. Single phase. My Google Fu
isn\'t very strong on this one. I remember Big Clive doing similar in one of his videos a while back
but have been unable to find that again.

Cheers,

See:
https://sound-au.com/articles/buck-xfmr.htm#s30

Explains \"the proper way\" to wire a buck boost. Both of the methods
shown work, one is just slightly more efficient.

My AC uses 7-8 amps so my 24 VCT transformer is rated at 10 amps or
240 VA.

Cheers. I have a 300 VA 50v output toriod in an amplifier that I want to re-use in an amp that
needs 40 - 45v AC. I\'ll get to calculating...

Toroids are great for that if they aren\'t potted. I used a pair of
large toroids from a surplus store for an audio power amp. The
voltage was borderline for the transistors I was using, so I wound a
few turns on the core and phased it to subtract voltage. I think it
was two turns of wire was ~.8 volts, and I wanted to go down 5 volts.

Interesting thanks, I\'ll consider that too. It\'s well wrapped but I might be able to work something
out. It\'s a project I haven\'t touched for a wee while now.

(I was also considering doing a small top-winding with insulated wire to get a low voltage out of
it for the speaker protection circuit I\'d like to fit rather than buying and including a second
transformer in the chassis.)
I used 16 AWG THHN stranded (high temp wire for conduit) and just
wired it on the outside and subtracted the out of phase voltage from
the secondary. Regulation may have suffered a bit but I had a lot of
filter capacitors, and low ESR photo-flash caps.
 
M

~misfit~

Guest
On 17/08/2020 7:50 pm, default wrote:
On Mon, 17 Aug 2020 17:31:43 +1200, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

On 12/08/2020 9:38 pm, default wrote:
On Wed, 12 Aug 2020 14:35:18 +1200, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

On 12/08/2020 9:19 am, default wrote:
On Tue, 11 Aug 2020 22:01:39 +1200, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

On 14/07/2020 8:08 am, etpm@whidbey.com wrote:
On Mon, 13 Jul 2020 11:31:30 -0400, default <default@defaulter.net
wrote:

I have an older window air conditioner that I\'d like to hang on to for
a few more years. The name plate says it is 220 VAC and since the
power company went through and upgraded the distribution network and
replaced HT and transformers my service which had been running 210-220
volts is now a steady 250 volts and my bill is up ~15%.

The increased consumption is tied to how much I run the AC and since
the upgrade I\'ve already had to replace both the compressor and fan
motor run caps. The compressor one died a quiet death, and the fan
cap melted and smoked. The compressor cap went out the week they
changed the transformer and the fan cap about a month later. I put in
higher voltage ones and the AC is back on line.

I was wondering if putting in 240 VAC to 24VAC center tapped, 10 amp
power transformer, wired to buck the voltage makes any sense?
Where I live we get 250 volts pretty steadily. In my shop are
several CNC machines, one of which cannot easily tolerate the 250
volts. So I use two buck/boost xmfrs wired in a particular buck
configuration to lower the 3 phase voltage going to that one machine.
Since doing so the machine has not once alarmede out due to over
voltage.
I also wired up a little 120 to 12 volt xmfr in buck configuration
to lower the 125 volts from the outlet to the 110 volts needed for a
tube amp.
There are directions online on how to select the proper sized xmfr
for the load it will be seeing and how to wire the thing in buck
configuration.
Eric


Eric could you please give me directions to on-line info? I\'m looking at dropping the voltage to a
transformer so that I get lower secondaries out of it inexpensively. Single phase. My Google Fu
isn\'t very strong on this one. I remember Big Clive doing similar in one of his videos a while back
but have been unable to find that again.

Cheers,

See:
https://sound-au.com/articles/buck-xfmr.htm#s30

Explains \"the proper way\" to wire a buck boost. Both of the methods
shown work, one is just slightly more efficient.

My AC uses 7-8 amps so my 24 VCT transformer is rated at 10 amps or
240 VA.

Cheers. I have a 300 VA 50v output toriod in an amplifier that I want to re-use in an amp that
needs 40 - 45v AC. I\'ll get to calculating...

Toroids are great for that if they aren\'t potted. I used a pair of
large toroids from a surplus store for an audio power amp. The
voltage was borderline for the transistors I was using, so I wound a
few turns on the core and phased it to subtract voltage. I think it
was two turns of wire was ~.8 volts, and I wanted to go down 5 volts.

Interesting thanks, I\'ll consider that too. It\'s well wrapped but I might be able to work something
out. It\'s a project I haven\'t touched for a wee while now.

(I was also considering doing a small top-winding with insulated wire to get a low voltage out of
it for the speaker protection circuit I\'d like to fit rather than buying and including a second
transformer in the chassis.)

I used 16 AWG THHN stranded (high temp wire for conduit) and just
wired it on the outside and subtracted the out of phase voltage from
the secondary. Regulation may have suffered a bit but I had a lot of
filter capacitors, and low ESR photo-flash caps.
Cheers.
--
Shaun.

\"Humans will have advanced a long, long way when religious belief has a cozy little classification
in the DSM\"
David Melville

This is not an email and hasn\'t been checked for viruses by any half-arsed self-promoting software.
 
M

Michael_A_Terrell

Guest
default wrote:
I have a wall-switch that disconnects the mains from the AC outlet. I
don\'t trust leaving it on and unattended when I\'m away.

I am curious about how they do the time delay though.... If the AC
power has been off for a time (several minutes) and I apply power the
compressor will run right away. Yet if I switch the mains off and on
quickly it goes into it\'s time delay.

I figure that they must be looking at the charge on a cap that
gradually bleeds off when power is removed - and prevents a re-start
and goes into it\'s timing cycle instead. Easy to implement with a
micro controller chip...
Here is a timer module for custom control systems. I will be using
one on my new well pump controls.

http://www.ebay.com/itm/383273947171

--
Never piss off an Engineer!

They don\'t get mad.

They don\'t get even.

They go for over unity! ;-)
 
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