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Author Topic: Taming my Shack Voltage From 252Vrms to 240Vrms  (Read 22670 times)
K9RJ
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Posts: 76




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« Reply #30 on: May 25, 2014, 06:33:04 PM »

When I had this problem some years ago, I called PG&E and they were happy to fix the problem. In the summer when AC loads and pool pumps max out the demand, they put capacitors on line to keep the voltage up. I explained I was losing light bulbs at a high rate and pilot lights in my stereo. They now seem to be able to keep it between 240 - 246 most of the time. I have an ACOM 2000A and it would also advise that the filament voltage was too high. Good luck. Harris K9RJ Alamo, CA
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W3RSW
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Posts: 606




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« Reply #31 on: May 26, 2014, 08:06:57 AM »

Their standard may not match Eimac's.  I would run those filaments at reasonably close to 5.0 volts at the tube sockets. You have enough unknowns from measuring instruments, etc. to have to contend with the high limit of a power company.
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Rick, W3RSW
KA5PIU
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Posts: 446




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« Reply #32 on: June 02, 2014, 06:26:32 PM »

Hello.

You want 240 and are getting 252 volts?
Dude, in Mexico we see 90 to 167 volts, and that is on the 120 side!
People buy 208  volt rated light bulbs.
Zenith TVs were the big thing, they hav
e switching power supplies that can deal with this, but they all do now.
Surge protectors need to be 220 volt rated, for the 120 circuits.
The amazing thing is that it all stays together.
The Mexican power company gets 50 Hz rated transformers as they seem to take this better.
But, 252 volts? not a problem.
And, I would not even consider a wal wart type of transformer in Mexico, they burst into flames all the time.
A switching supply is what you want down there.
Cellphone chargers rated for 110/220 do well.
self regulating light bulbs, although more expensive, are the way to go.
Electronic ballasts for florescent and CFL are really the way to go.
For a small base station, a regumax, a small inline AC regulator, is the way to go.
If your radio has 120/240 taps, a mini regumax can be installed inside.
Remember, this is Mexico.
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KD2ACO
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« Reply #33 on: June 04, 2014, 08:54:36 PM »

Approaching Summer in Yonkers, NY, I'm expecting about 90 volts on my mains. Can you please send several of your volts UPS ground? I'll be glad to pay for shipping!
73
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KA5PIU
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« Reply #34 on: June 04, 2014, 10:13:23 PM »

Approaching Summer in Yonkers, NY, I'm expecting about 90 volts on my mains. Can you please send several of your volts UPS ground? I'll be glad to pay for shipping!
73

90 volts? and it is not MEXICO!?
I actually expect this in Mexico.
Brown outs, where they cut the voltage, is not uncommon.
The trick for just a few volts is a multi tap filament transformer.
A 6-12-24 volt transformer rated 15 amps works wonders for one circuit.
The transformer primary is connected like normal.
But, the secondary is connected in series with the hot lead, after the transformer primary.
Lets say 90 volts.
The transformer is only doing 90 volts in, so boost is going to be reduced.
Figure on 20 volts boost.
So, 90 volts and 20, 110.
Before anyone gets excited, this is very common in Mexico, and never any trouble.
It is the secondary that carries the current.
And, proper mounting in a steel can is the norm.
Mineral oil filled units are much quieter, and I have seen them in gallon paint cans.
But, this is Mexico.
You can build something like it.
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KD2ACO
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« Reply #35 on: June 05, 2014, 11:59:14 AM »

A transformer burned in my hood last year and ConEd just hooked my block onto the next one's (now very overloaded) transformer. They say they'll fix it soon... I've got a General Radio automatic variac on the house so my voltage is always 121!
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KA5PIU
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« Reply #36 on: June 05, 2014, 10:33:17 PM »

A transformer burned in my hood last year and ConEd just hooked my block onto the next one's (now very overloaded) transformer. They say they'll fix it soon... I've got a General Radio automatic variac on the house so my voltage is always 121!
One transformer per block?
In San antonio Texas they have one transformer per 2 to 4 houses.
In Los Mochis Sinaloa MX they do the same.
If a transformer fails, they put in a new one by the next day in San Antonio.
By the end of the week in Sinaloa.
And, they know that the transformers get undersized due to increased demand.
In Mexico, you have the option of buying a transformer.
We paid extra for an Allis Chamers self regulating transformer and set it for 121 volts in Mexico.
It was 200% oversize when installed but now running at ratings.
It has split windings so can deliver 110/220 center ground and 230 end ground.
The electric company never quite figured that one out, so the 230 high is not metered.
Yes, there are 4 wires off the transformer to the building.
The 230 is only rated to 22 amps, so it is not that big a deal.
In Mexico, they use both the US standard, and the European standard.
The US outlets are standard.
But the building also has the European sockets.
This has been in place since the 70's.
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KA5PIU
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Posts: 446




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« Reply #37 on: June 05, 2014, 11:45:50 PM »

Hello.

Found references to the type of transformer.
This is a "Service secondary" and a "Control secondary".
The control secondary is 2 windings with a center tap.
The center tap is not connected.
The reason for 230 is that the small gauge white wire can not carry much current.
This is one large uninsulated, 2 large black insulated and one much smaller white insulated.
It goes into the meter can, 2 black to the terminal block with the uninsulated down the center.
The white wire goes beside everything.
Everything goes to the main breaker, except the white wire, it goes to an inline fuse, 22 amp.
In the UK, 13 and 22 amps are standard.
But, again, the white wire is not metered.
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KD2ACO
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« Reply #38 on: June 06, 2014, 04:07:40 AM »

Here's how it goes with ConEd... 20 years ago, I lived in Briarcliff Manor, a kinda expensive town 1 hour north of Manhattan. The house and recording studio I lived in was suffering line noise from an auto body shop's welding equipment, so I bought a nice transformer to put my place on. ConEd put it up on the pole and everything was fine for 3 months. I started having noise problems again and looked at the pole. The auto shop was hooked back onto my transformer. Calling Conned by Ed to ask them WTF and was told that the tformer became theirs as soon as it went up on the pole and screw me, there's nothing I can do to tell them what to do with their distribution system. That lesson learned, I just take what they give me and condition it in my house. That works great!
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KA5PIU
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Posts: 446




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« Reply #39 on: June 06, 2014, 04:28:29 AM »

Here's how it goes with ConEd... 20 years ago, I lived in Briarcliff Manor, a kinda expensive town 1 hour north of Manhattan. The house and recording studio I lived in was suffering line noise from an auto body shop's welding equipment, so I bought a nice transformer to put my place on. ConEd put it up on the pole and everything was fine for 3 months. I started having noise problems again and looked at the pole. The auto shop was hooked back onto my transformer. Calling Conned by Ed to ask them WTF and was told that the tformer became theirs as soon as it went up on the pole and screw me, there's nothing I can do to tell them what to do with their distribution system. That lesson learned, I just take what they give me and condition it in my house. That works great!
So, you BUY a transformer, and ConEd puts someone else on it?
Yes, they do this in Mexico as well!
So, you pay extra and have them put it on a pole in your yard, about $100 extra.
The hassle of running extra wires to it make it not worth the effort.
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N1UK
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« Reply #40 on: June 13, 2014, 01:07:26 PM »

I am lucky to be in the country. I have a 600 amp transformer on a pole which feeds just my house. I have a 400 amp drop to my house with two 200 amp load centers. I have plenty of unused circuit breaker slots and was able to run 100 amps 240V to my barn without worrying about it.

I have installed a 30 amp variac in the shack now. I am in the process of building a 120V contactor box, so that the variac is only energised when I am operating my station.


Mark N1UK
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KA5PIU
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Posts: 446




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« Reply #41 on: June 13, 2014, 02:07:15 PM »

Hello.

600 amp!
The thing out here is rated for 200 amps.
That is pretty much the standard size.
In Mexico, a 200 amp transformer, good for at least 5 or 6 houses.
You will see where people have bought their transformer and the people who are on the "community" transformer.
The local community transformer is always the one with trouble.
One day I heard one making bubbling sounds and smoke coming out.
I was told that it was normal, they do that!
Nobody wants to pay extra for a lager transformer or buy one.
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N1UK
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« Reply #42 on: June 13, 2014, 04:08:21 PM »

Originally this house had electric heating. 100 amps 240V upstairs and 100 amp 240V downstairs, so that pretty much took care of the first 200 amps. A second standard 200 amp panel was then added for the water heaters, a/c units, lighting etc.

I have since removed the electric heating and now have plenty of power for this house hi hi


Mark N1UK
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