I am working on a 1936 Howard model 68
http://www.nostalgiaair.org/PagesByModel/342/M0009342.pdf

This radio uses one of those old 'acorn-shaped' 1 volt bias cells to place constant bias the grid on the 6Q7.

The guy who sold it to me or somebody before him had "fixed" this chicken-coop wonder to get it working with little more than a lick and a promise.
He replaced only what was actually needed to make it work. What a filty sloppy repair job.
AND he left all the paper caps still in except one...and about 1/2 of the rest of the paper caps were almost completely chewed through by a mouse or something. Big shreds of aluminium hanging out.
The rotten filthy power cord was just hand twisted on the terminals no solder. An even older AC cord was sniped off and stub left hanging on the on/off pot..
A nightmare.
BUT... the radio was working... but it sure needed a ton of clean-up.

Interestingly the 1 volt bias cell doesn't seem to matter on or off.

It was connected but dead. So it's the same as an open I guess. With a 1 meg resistor just hanging in the breeze on the grid of the 6Q7. Grid is fed from volume control via .02uf.
I hooked up a 1-1/2 volt AA battery to try.
Well it works in or out ....even reversing the polarity.. So I removed the bias cell and grounded the 1 meg and that worked too of course.
But I wanted to get it operating properly. I read on the Philco repair bench site all about rejuvinating these cells so I thought I'd try it.
Now I could just stick a watch battery cell in there and maybe eventually I will ....but in the mean time I rejuvinated this 70 yo bias cell successfully.
( I think)

I hand drilled a tiny hole in the positive side (carbon) and then injected a couple drops of water with a hypodermic. Then a couple drops of white-glue to seal the hole.
Within a few minuets the cell was reading .9 volts.

So now I put it back in and it sure seems to actually be working.
I'm reading a solid -.86v on the grid now prior to power up and after power up as well.
Not sure exactly what it's really supposed to be though.
Without the cell it floats at about -.84v anyway after power up.

So it was a nice excercise in restoring a 70 yo battery.

B+ related question on Voltages:
A curious question I have though is that some of the other listed voltages on the print are actually much higher than called for on the print.
Now the B+ is 20volts higher than the print anyway... up at +255v because of my 125v AC feed and the new filter caps..I guess??..
... so I'd expect readings to be a bit higher... but not like this.

Absolutley ALL the surrounding and contributing components have been very carefully measured exactly and/or replaced. So I know for certain that I absolutley don't have drifted values causing this.

The plate of the 6Q7 is supposed to be only +35volts according to the print.
.. but I read +95 volts !!!
The cathode is grounded and the grid is at -.85v .

So this makes no sense to me... unless they made a mistake on the print.

The other somewhat curious area of higher voltage is the Screen Grids of the 6A7 and the 6K7.
The print says +98volts but I read +125v... now maybe this area is really ok because the B+ is already 20V high too and the screens are 20v higher.

BUT... back at the plate of the 6Q7 it has me stumped.
Should it be drawing a lot more current and pulling the plate down to 35volts??
35 volts seems awfully low to me though.
A new 6Q7 stuck in there measures the same as well.

Any ideas why?

Radio is playing and tuning like a dream now ...by the way.

Hi, Peter.

I think there is a gap between theory and practice when it comes to grid bias. Some of my TRF sets play fine without a C voltage hooked up or with the detector grid-leak resistor removed from the ckt.

Regarding the high B+. Did you up-size the filter caps? That can cause it. Also, the specified volatages are for 115V line input. If yours are at 125, that's 10V high; but need to multiply by sqrt2 = 1.414, so it's really and extra 14V on the DC side of the rectifier.

Finally, the specified voltages were probably based on using an old low-impedance voltmeter. They would have dragged some of the voltages down, e.g. plate on the 6Q7. You're using a high-impedance DMM?

The tube manuals show 100V plate voltage for a 6Q7 in detector duty. I think 35V is just what was measured with an old meter.

:I am working on a 1936 Howard model 68
:http://www.nostalgiaair.org/PagesByModel/342/M0009342.pdf
:
:This radio uses one of those old 'acorn-shaped' 1 volt bias cells to place constant bias the grid on the 6Q7.
:
:The guy who sold it to me or somebody before him had "fixed" this chicken-coop wonder to get it working with little more than a lick and a promise.
:He replaced only what was actually needed to make it work. What a filty sloppy repair job.
:AND he left all the paper caps still in except one...and about 1/2 of the rest of the paper caps were almost completely chewed through by a mouse or something. Big shreds of aluminium hanging out.
:The rotten filthy power cord was just hand twisted on the terminals no solder. An even older AC cord was sniped off and stub left hanging on the on/off pot..
:A nightmare.
:BUT... the radio was working... but it sure needed a ton of clean-up.
:
:Interestingly the 1 volt bias cell doesn't seem to matter on or off.
:
:It was connected but dead. So it's the same as an open I guess. With a 1 meg resistor just hanging in the breeze on the grid of the 6Q7. Grid is fed from volume control via .02uf.
:I hooked up a 1-1/2 volt AA battery to try.
:Well it works in or out ....even reversing the polarity.. So I removed the bias cell and grounded the 1 meg and that worked too of course.
:But I wanted to get it operating properly. I read on the Philco repair bench site all about rejuvinating these cells so I thought I'd try it.
:Now I could just stick a watch battery cell in there and maybe eventually I will ....but in the mean time I rejuvinated this 70 yo bias cell successfully.
:( I think)
:
:I hand drilled a tiny hole in the positive side (carbon) and then injected a couple drops of water with a hypodermic. Then a couple drops of white-glue to seal the hole.
:Within a few minuets the cell was reading .9 volts.
:
:So now I put it back in and it sure seems to actually be working.
:I'm reading a solid -.86v on the grid now prior to power up and after power up as well.
:Not sure exactly what it's really supposed to be though.
:Without the cell it floats at about -.84v anyway after power up.
:
:So it was a nice excercise in restoring a 70 yo battery.
:
:B+ related question on Voltages:
:A curious question I have though is that some of the other listed voltages on the print are actually much higher than called for on the print.
:Now the B+ is 20volts higher than the print anyway... up at +255v because of my 125v AC feed and the new filter caps..I guess??..
:... so I'd expect readings to be a bit higher... but not like this.
:
:Absolutley ALL the surrounding and contributing components have been very carefully measured exactly and/or replaced. So I know for certain that I absolutley don't have drifted values causing this.
:
:The plate of the 6Q7 is supposed to be only +35volts according to the print.
:.. but I read +95 volts !!!
:The cathode is grounded and the grid is at -.85v .
:
:So this makes no sense to me... unless they made a mistake on the print.
:
:The other somewhat curious area of higher voltage is the Screen Grids of the 6A7 and the 6K7.
:The print says +98volts but I read +125v... now maybe this area is really ok because the B+ is already 20V high too and the screens are 20v higher.
:
:BUT... back at the plate of the 6Q7 it has me stumped.
:Should it be drawing a lot more current and pulling the plate down to 35volts??
:35 volts seems awfully low to me though.
:A new 6Q7 stuck in there measures the same as well.
:
:Any ideas why?
:
:Radio is playing and tuning like a dream now ...by the way.
:
:
:
:
:
:
:

Thanks Doug.. perhaps you are right. I am using a DMM but I'll try reading the same point with my analog multi-meter later.
I kept the filter caps almost the same. I replaced the two 8uf caps with 10uf.

Hi! My thinking is that your measured 95-V plate voltage is almost spot-on with the RCA tube manual's recommended voltage of 100V. Why is it a little less? Check those two resistors in series with the plate -- maybe the've drifted up a little? (If so, I'd tend to leave them alone -- your plate voltage is good enough.)

Your analog mutli-meter might have different ohms/volt than what Howard used in the 1930s for their schematic voltages. So, if your readings with your analog meter are different from 35V, I wouldn't worry about it too much.

:Thanks Doug.. perhaps you are right. I am using a DMM but I'll try reading the same point with my analog multi-meter later.
:I kept the filter caps almost the same. I replaced the two 8uf caps with 10uf.
:

They often used a 1,000 ohm per volt meter back then. Your 20,000 ohm per volt anolog meter still won't load down the circuit like their's did. Honestly I don't know why any large radio establishment like that would ever use a 1,000 ohm per volt meter to read plate voltages through a 1 meg resistor, or grid bias voltages. Still, many manufacturers did this. If you change things so that you have a true 35 volts on your 6Q7, you will be disappointed with its performance.

Thomas

The DC on the rectifier cathode is now at around 360 insted of the 320 written on the print from back in days of about 105vAC input.
.
After the field coil it's close to 265

I measured around 90vDc on the plate tonight with the DMM
My Analog meter only read 85v... so slight loading..

The tube data on a 6Q7, as class A, shows 100v on the plate and plate current of only .35ma

The B+ tonight was around 265dc
and.

..Tonight there was 90v on the 6Q7 plate and I measured the actual current as about .65ma... nearly twice the .35ma shown in class A.

I have two plate resistors with a .25uf cap to ground at the junction (220k & 47k) totalling actually about 270k ohm
...so at .65ma the voltage drop of about 175 volts across these two resistors is leaving me with 90v on the plate.
Seems right... that is if .65ma is the correct plate current for this circuit design.

I can only assume that manufacturers used low-impedance voltmeters for their schematics because they thought that's what repairmen would use?

But anyway, let's assume that the voltage readings were based on using a 1000-ohms/volt meter. On a 100-V scale, that would be 100K. So, temporarily strap a 100K resistor across where you're measuring the plate voltage. Then measure the voltage with your DMM.

The 6Q7 plate current @ 100V is listed at 0.8mA in the RCA receving tube manual.

Your higher line voltage would cause all the set's voltages to be nearly 10% higher than specified.

:They often used a 1,000 ohm per volt meter back then. Your 20,000 ohm per volt anolog meter still won't load down the circuit like their's did. Honestly I don't know why any large radio establishment like that would ever use a 1,000 ohm per volt meter to read plate voltages through a 1 meg resistor, or grid bias voltages. Still, many manufacturers did this. If you change things so that you have a true 35 volts on your 6Q7, you will be disappointed with its performance.
:
:Thomas

If the old meter were on a 50-V scale, input impedence would be 50K. Maybe use that for your test.

:I can only assume that manufacturers used low-impedance voltmeters for their schematics because they thought that's what repairmen would use?
:
:But anyway, let's assume that the voltage readings were based on using a 1000-ohms/volt meter. On a 100-V scale, that would be 100K. So, temporarily strap a 100K resistor across where you're measuring the plate voltage. Then measure the voltage with your DMM.
:
:The 6Q7 plate current @ 100V is listed at 0.8mA in the RCA receving tube manual.
:
:Your higher line voltage would cause all the set's voltages to be nearly 10% higher than specified.
:
:
:
::They often used a 1,000 ohm per volt meter back then. Your 20,000 ohm per volt anolog meter still won't load down the circuit like their's did. Honestly I don't know why any large radio establishment like that would ever use a 1,000 ohm per volt meter to read plate voltages through a 1 meg resistor, or grid bias voltages. Still, many manufacturers did this. If you change things so that you have a true 35 volts on your 6Q7, you will be disappointed with its performance.
::
::Thomas

Hi

Differences in meter reading are noticed where voltages are supplied through large value resistors. In most radios this is the 1st audio amp, plate. Figure voltage should be around 1/2 supply. If one side of the resistor has 200 volts ideally the other will read 100.

Many meters were 1000ohms/volt years ago. More sensitive meters would have been too expensive. Resistors can be added as Doug suggested but in time we learn what voltage to expect.

I prefer using 20K/volt meters such as Triplett 630 or Simpson 260. They have a analog movement, load the circuit very little and don't req

:If the old meter were on a 50-V scale, input impedence would be 50K. Maybe use that for your test.
:
::I can only assume that manufacturers used low-impedance voltmeters for their schematics because they thought that's what repairmen would use?
::
::But anyway, let's assume that the voltage readings were based on using a 1000-ohms/volt meter. On a 100-V scale, that would be 100K. So, temporarily strap a 100K resistor across where you're measuring the plate voltage. Then measure the voltage with your DMM.
::
::The 6Q7 plate current @ 100V is listed at 0.8mA in the RCA receving tube manual.
::
::Your higher line voltage would cause all the set's voltages to be nearly 10% higher than specified.
::
::
::
:::They often used a 1,000 ohm per volt meter back then. Your 20,000 ohm per volt anolog meter still won't load down the circuit like their's did. Honestly I don't know why any large radio establishment like that would ever use a 1,000 ohm per volt meter to read plate voltages through a 1 meg resistor, or grid bias voltages. Still, many manufacturers did this. If you change things so that you have a true 35 volts on your 6Q7, you will be disappointed with its performance.
:::
:::Thomas

:Hi
:
: Differences in meter readings are noticed where voltages are supplied through large value resistors. In most radios this is the 1st audio amp, plate. Figure voltage should be around 1/2 supply. If one side of the resistor has 200 volts ideally the other will read 100.
:
: Many meters were 1000ohms/volt years ago. More sensitive meters would have been too expensive. Resistors can be added as Doug suggested but in time we learn what voltage to expect.
:
: I prefer using 20K/volt meters such as Triplett 630 or Simpson 260. They have an analog movement, load the circuit very little and don't require external power.

Norm
:
:
:
:
::If the old meter were on a 50-V scale, input impedence would be 50K. Maybe use that for your test.
::
:::I can only assume that manufacturers used low-impedance voltmeters for their schematics because they thought that's what repairmen would use?
:::
:::But anyway, let's assume that the voltage readings were based on using a 1000-ohms/volt meter. On a 100-V scale, that would be 100K. So, temporarily strap a 100K resistor across where you're measuring the plate voltage. Then measure the voltage with your DMM.
:::
:::The 6Q7 plate current @ 100V is listed at 0.8mA in the RCA receving tube manual.
:::
:::Your higher line voltage would cause all the set's voltages to be nearly 10% higher than specified.
:::
:::
:::
::::They often used a 1,000 ohm per volt meter back then. Your 20,000 ohm per volt anolog meter still won't load down the circuit like their's did. Honestly I don't know why any large radio establishment like that would ever use a 1,000 ohm per volt meter to read plate voltages through a 1 meg resistor, or grid bias voltages. Still, many manufacturers did this. If you change things so that you have a true 35 volts on your 6Q7, you will be disappointed with its performance.
::::
::::Thomas

Thanks Guys...
I didn't use my RCA receiving tube manual.. but
I was taking my tube data info from here:

http://nj7p.org/Tube4.php?tube=6q7

there for class A, they show 100v on the plate @ .35ma

Actually, the line voltage in many places back then was around 115. There were many homes with 120 volts, some with 130 (or there-about), and numerous with 110. I read somewhere that where a house was fed with only two wires, you could expect to see 105 to 110. Don't know why this is so. Voltage is independent of wire count. It only depends on the voltage being supplied by the power company and the windings in the power transformer. Oh well. I wonder if the two wire/three wire voltage difference was actually true. I know of many houses in Mexico that only have two wire feeds (and only two fuses). Most of these houses run at about 125 volts. Bulbs and appliances are rated accordingly.

Thomas

The Howard radio schematics say that voltages are meaured @ 115V line voltage with no antenna input.

Nowadays, in the US, (most) all residential services have three wires. State public service commissions usually specify the acceptable range of delivered voltages, but who knows?

Thomas, the next time I go to Mexico, I might just take my DMM. Many of the residential electrical service connections, in Oaxaca at least, are more or less exposed right on the building wall at the street, about 5' high, so checking voltage would be a snap.

:Actually, the line voltage in many places back then was around 115. There were many homes with 120 volts, some with 130 (or there-about), and numerous with 110. I read somewhere that where a house was fed with only two wires, you could expect to see 105 to 110. Don't know why this is so. Voltage is independent of wire count. It only depends on the voltage being supplied by the power company and the windings in the power transformer. Oh well. I wonder if the two wire/three wire voltage difference was actually true. I know of many houses in Mexico that only have two wire feeds (and only two fuses). Most of these houses run at about 125 volts. Bulbs and appliances are rated accordingly.
:
:Thomas

:Actually, the line voltage in many places back then was around 115. There were many homes with 120 volts, some with 130 (or there-about), and numerous with 110. I read somewhere that where a house was fed with only two wires, you could expect to see 105 to 110. Don't know why this is so. Voltage is independent of wire count. It only depends on the voltage being supplied by the power company and the windings in the power transformer. Oh well. I wonder if the two wire/three wire voltage difference was actually true. I know of many houses in Mexico that only have two wire feeds (and only two fuses). Most of these houses run at about 125 volts. Bulbs and appliances are rated accordingly.
:
:Thomas

Hi: I found your comments very intresting. I read all the posts almost every evening. Me and the boy next door 'wired' farm houses back in the fourties, here in southern Ohio. The Rural Electrification Association, a government agency was building power lines though the hills and hollers here. In most houses we installed a small 30 amp two pole box with two plug fuses. Two wires came from, usually a 2.5 KVA transformer. Many times the family would have a farm radio that operated from a 6 volt car battery. So my friend and I, being avid readers of Science and Mechanics and other Gernsback publications began offering to convert these to 110 as we called it. We would order tube sockets, rectifier tubes and power transformers from Olsen Radio in Acron,Ohio. Susprisingly some of these radios worked pretty good. Most folks could tune in to WLW Cincinnati,Oh, WJJD in Chicago and WLS in Renfro VAlley, Ky. I saw many people throw out their floor model Zeniths and Crosleys and get a new plastic cased ACDC five tube set. I still have a twelve tube Beverly console case.
It was a TRF set that I rescued from the town dump over fifty years ago. Regrettably it's gizzard is missing. A lady had used the case as a shelf to store quilts in. It still has great veneer.
"Old men are given to much talking."
Keep up the good work.
Ivan Copas

::Actually, the line voltage in many places back then was around 115. There were many homes with 120 volts, some with 130 (or there-about), and numerous with 110. I read somewhere that where a house was fed with only two wires, you could expect to see 105 to 110. Don't know why this is so. Voltage is independent of wire count. It only depends on the voltage being supplied by the power company and the windings in the power transformer. Oh well. I wonder if the two wire/three wire voltage difference was actually true. I know of many houses in Mexico that only have two wire feeds (and only two fuses). Most of these houses run at about 125 volts. Bulbs and appliances are rated accordingly.
::
::Thomas
Ivan,
Very Interesting. Most of my radios and antique trunks came from that area/era in WV, and the old time stations you mentioned were my standards of those days (40's-50's) Still remember the old glass, screw-in fuses that blew and melted into the innards of a switch box, setting the house on fire during a summer lightning storm, and those were the "good old days"

marv

:
:Hi: I found your comments very intresting. I read all the posts almost every evening. Me and the boy

next door 'wired' farm houses back in the fourties, here in southern Ohio. The Rural Electrification Association, a government agency was building power lines though the hills and hollers here. In most houses we installed a small 30 amp two pole box with two plug fuses. Two wires came from, usually a 2.5 KVA transformer. Many times the family would have a farm radio that operated from a 6 volt car battery. So my friend and I, being avid readers of Science and Mechanics and other Gernsback publications began offering to convert these to 110 as we called it. We would order tube sockets, rectifier tubes and power transformers from Olsen Radio in Acron,Ohio. Susprisingly some of these radios worked pretty good. Most folks could tune in to WLW Cincinnati,Oh, WJJD in Chicago and WLS in Renfro VAlley, Ky. I saw many people throw out their floor model Zeniths and Crosleys and get a new plastic cased ACDC five tube set. I still have a twelve tube Beverly console case.
:It was a TRF set that I rescued from the town dump over fifty years ago. Regrettably it's gizzard is missing. A lady had used the case as a shelf to store quilts in. It still has great veneer.
:"Old men are given to much talking."
:Keep up the good work.
:Ivan Copas

I have never had one of my fuses start the box on fire. I've blown them several times when I run two air conditioners on one circuit, and then turn on too many lights (or when my air conditioners need a cleaning). The fuses can get quite hot, though. It angers me to know that everyone else in my building has 20s and 30s screwed into their boxes. I should call the health department and have them raid my building. I've always liked fuses because they are non-mechanical, and cannot stick. I realize, though, that they can be hazardous when people like those who live in my building use them.

I wonder, though, how the fuses you encountered happened to start the box on fire. That is interesting. I also recently discovered that circuit breakers have a very interesting magnetic device in them that will really quickly trip them in the event of a sudden heavy overload. With a fuse, you must wait for the little strip to melt, which usually isn't very long, but is long enough to allow wires to weld.

Thomas

Thomas, landlords should install inexpensive "fustats" throughout any rental building with common plug fuses: http://www.bussmann.com/products/Electrical/Group11.asp

Once the fustat adapter is screwed into the fuse socket, then only the correct ampere fuse can be used.

Any circuit with a motor, like an air conditioner, should be protected with a time-delay fuse, which are available in fustat configuration.

:I have never had one of my fuses start the box on fire. I've blown them several times when I run two air conditioners on one circuit, and then turn on too many lights (or when my air conditioners need a cleaning). The fuses can get quite hot, though. It angers me to know that everyone else in my building has 20s and 30s screwed into their boxes. I should call the health department and have them raid my building. I've always liked fuses because they are non-mechanical, and cannot stick. I realize, though, that they can be hazardous when people like those who live in my building use them.
:
:I wonder, though, how the fuses you encountered happened to start the box on fire. That is interesting. I also recently discovered that circuit breakers have a very interesting magnetic device in them that will really quickly trip them in the event of a sudden heavy overload. With a fuse, you must wait for the little strip to melt, which usually isn't very long, but is long enough to allow wires to weld.
:
:Thomas

My grandmother had these. Smart idea sort-of. I found that you could still force the wrong fuse in if you tried hard enough (someone also was brilliant enough to put a 20 adapter into the kitchen socket, so now the kitchen is forever a 20 even though the wiring is only rated for 15!). You know, though, I should change my box over to Fustats. That'd at least make my appartment more safe for the next guy. When I moved in, my box was filled with 30s. I quickly changed them all to 15s. I don't understand why only 3 of the 4 sockets are used. This place could be more flexible if all 4 were used. Many rooms, though, have only 1 outlet. My living room has a whopping two, and my kitchen, which originally had two, now has three. I'm thinking about adding some more outlets like in my hallway.

T.

Thomas,
The same lightning bolt that melted the fuses came in through the power and telephone line. The house didn't burn, but 2 fires were ignited from the energy dissipated into flammable objects.

marv

:I have never had one of my fuses start the box on fire. I've blown them several times when I run two air conditioners on one circuit, and then turn on too many lights (or when my air conditioners need a cleaning). The fuses can get quite hot, though. It angers me to know that everyone else in my building has 20s and 30s screwed into their boxes. I should call the health department and have them raid my building. I've always liked fuses because they are non-mechanical, and cannot stick. I realize, though, that they can be hazardous when people like those who live in my building use them.
:
:I wonder, though, how the fuses you encountered happened to start the box on fire. That is interesting. I also recently discovered that circuit breakers have a very interesting magnetic device in them that will really quickly trip them in the event of a sudden heavy overload. With a fuse, you must wait for the little strip to melt, which usually isn't very long, but is long enough to allow wires to weld.
:
:Thomas

:Actually, the line voltage in many places back then was around 115. There were many homes with 120 volts, some with 130 (or there-about), and numerous with 110. I read somewhere that where a house was fed with only two wires, you could expect to see 105 to 110. Don't know why this is so. Voltage is independent of wire count. It only depends on the voltage being supplied by the power company and the windings in the power transformer. Oh well. I wonder if the two wire/three wire voltage difference was actually true. I know of many houses in Mexico that only have two wire feeds (and only two fuses). Most of these houses run at about 125 volts. Bulbs and appliances are rated accordingly.
:
:Thomas

Thomas,

Two wires, three wires--Two wires can only deliver one voltage level. Three wires deliver two 120 volt circits that are 180 degrees out of phase which gives 120 to neutral and 240 between the two hot wires. That's why you never disconnect the neutral at the load center. If you did that you would have 240 volts on every circuit in your house. Most commercial installations have four wire service with three hot phases 120 degrees out of phase for 208 volts phase to phase and 120 phase to neutral. The main frame computers that I maintained in the '60's ran on 208 three phase and even with sequencing drew about 70 amps per phase on power-up.

Will

::Actually, the line voltage in many places back then was around 115. There were many homes with 120 volts, some with 130 (or there-about), and numerous with 110. I read somewhere that where a house was fed with only two wires, you could expect to see 105 to 110. Don't know why this is so. Voltage is independent of wire count. It only depends on the voltage being supplied by the power company and the windings in the power transformer. Oh well. I wonder if the two wire/three wire voltage difference was actually true. I know of many houses in Mexico that only have two wire feeds (and only two fuses). Most of these houses run at about 125 volts. Bulbs and appliances are rated accordingly.
::
::Thomas
:
:
:Thomas,
:
:Two wires, three wires--Two wires can only deliver one voltage level. Three wires deliver two 120 volt circits that are 180 degrees out of phase which gives 120 to neutral and 240 between the two hot wires. That's why you never disconnect the neutral at the load center. If you did that you would have 240 volts on every circuit in your house. Most commercial installations have four wire service with three hot phases 120 degrees out of phase for 208 volts phase to phase and 120 phase to neutral. The main frame computers that I maintained in the '60's ran on 208 three phase and even with sequencing drew about 70 amps per phase on power-up.
:
:Will

Sorry, that's circuits not circits,

I understand how the circuits work that go into your home (they're just like the high voltage winding in an AC radio). What I'm saying is that it was stated in an old book of mine that if your home had a two wire feeder, you could expect 107 volts, and a 3 wire would deliver 115. I have no idea why this was stated. Perhaps this was so in a certain area, but as I was saying before, and as I fully understand, voltage is entirely independent on wire count as far as home circuits are concerned, and yes, I do know that across the ends of the transformer secondary you'll get from 220 to 240, depending on what the transformer is rated for, and I'm sure that there are plenty of other voltages, too, like 207 or 277, and many more. I should have never brought this up, though, because I knew that it would lead to confusion.

Thomas

:I understand how the circuits work that go into your home (they're just like the high voltage winding in an AC radio). What I'm saying is that it was stated in an old book of mine that if your home had a two wire feeder, you could expect 107 volts, and a 3 wire would deliver 115. I have no idea why this was stated. Perhaps this was so in a certain area, but as I was saying before, and as I fully understand, voltage is entirely independent on wire count as far as home circuits are concerned, and yes, I do know

that across the ends of the transformer secondary you'll get from 220 to 240, depending on what the transformer is rated for, and I'm sure that there are plenty of other voltages, too, like 207 or 277, and many more. I should have never brought this up, though, because I knew that it would lead to confusion.
:
:Thomas

Thomas,
Let's get really confusing and discuss delta and Y transformer configurations and how to identify the "wild leg". On second thought let's don't but we can say we did. About two years ago I noticed one rainy night that the lights in some rooms were very bright and in other rooms they were very dim. I metered the wall sockets and found some at 175 volts and others at 80 Volts. I turned off the main breaker and called the power company and they came right out. After checking our load center, the meter, and the connections at the pole, they went up the other pole to the transformer and found a faulty connection there. They repaired it but then we found that the heat pump wouldn't start. The high voltage had blown it's controller. Wonder of wonders, the power company paid the bill for the heat pump repair.

Will

I'm surprised that you'd have this problem on a rainy night. My parents had this problem. It was due to a poor ground wire and ground plate. If you turned on the washing machine, lights on the other circuit got brighter.

I consistently have high voltage (over 125) in my appartment. I complained to my power company, and they came over to test everything. They never tested inside of my appartment, but believed what my Simpson 260 said. However, they went down to my meter and only found 121, which they said was acceptable. They said that my problem is due to a faulty ground. Well, if someone else is drawing excessive current, and I'm only on one phase (possible, since I only have 3 fuses), and they're on the other, this could happen. However, the voltage is always this high. I've even tested my kitchen with one or two toasters running. I've tested the refrigerator circuit (it even gets its own fuse! WOW!). I've tested the place in the winter, when noone else is running air conditioners. It's still always high! I think that the electric company is just lying to me so that they can avoid work. I should test all of the washing machine outlets in the basement and see what they read, especially with the machines running.

T.

:I'm surprised that you'd have this problem on a rainy night. My parents had this problem. It was due to a poor ground wire and ground plate. If you turned on the washing machine, lights on the other circuit got brighter.
:
:I consistently have high voltage (over 125) in my appartment. I complained to my power company, and they came over to test everything. They never tested inside of my appartment, but believed what my Simpson 260 said. However, they went down to my meter and only found 121, which they said was acceptable. They said that my problem is due to a faulty ground. Well, if someone else is drawing excessive current, and I'm only on one phase (possible, since I only have 3 fuses), and they're on the other, this could happen. However, the voltage is always this high. I've even tested my kitchen with one or two toasters running. I've tested the refrigerator circuit (it even gets its own fuse! WOW!). I've tested the place in the winter, when noone else is running air conditioners. It's still always high! I think that the electric company is just lying to me so that they can avoid work. I should test all of the washing machine outlets in the basement and see what they read, especially with the machines running.
:
:T.

Thomas,
Sounds like a load imbalance. They probably supply the building with 208 three phase and the loads aren't balanced close enough phase to phase. I don't recall exactly how this works but it was something that we had to verify on a computer installation. We had a clamp on amp meter that we would use to check each main at the computer room load center and then attempt to balance the load by rearrangeing the hoses to the various cabinets and periferals. We're on a rural electric co-op here and they give us really good service. One of the good things is that they are a not for profit utility and we get a refund check each December for our share of the profits. Usually about $200 to $300. We're on their dual fuel plan (heat pump with propane backup) and they sell us electricity for the heat pump at 1/2 price from November to March. The heat pump shuts off at 15 degrees and the propane comes on. This helps with their peak demand situation.

Will

Possible. (sorry, Peter, for turning this thread into a fuse/AC questionaire) How do they divide 208 volts into 120? It might make sense since there are 9 units. It could theoretically be divided into three parts. My stove runs at 220 (or 240), though. Maybe it's running at 208? Originally, in 1927, and probably for the majority of this building's life, each appartment had 3 fuses (4, but one is unused for some unknown reason). Now, however, some have dishwashers. There are extra wires for those. They didn't tap off of the original wiring (thank goodness!).

T.

:Possible. (sorry, Peter, for turning this thread into a fuse/AC questionaire) How do they divide 208 volts into 120? It might make sense since there are 9 units. It could theoretically be divided into three parts. My stove runs at 220 (or 240), though. Maybe it's running at 208? Originally, in 1927, and probably for the majority of this building's life, each appartment had 3 fuses (4, but one is unused for some unknown reason). Now, however, some have dishwashers. There are extra wires for those. They didn't tap off of the original wiring (thank goodness!).
:
:T.

Thomas.
The three phases are all 120 volt phases so any phase to neutral is 120 volts, but since they are 120 degrees out of phase with each other the voltage is only 208 phase to phase. I think that anything that runs on 220/240 will probably run on 208.
Will

Ah. Seems to be that the thing is rated for 120/240, 120/208, so I guess whatever they did to the stove (conversion for this particular voltage) allows it to run at 208. Amazing the things I learn on this site every day. Too bad you guys can't teach me Spanish. I'm trying to get my roommate to speak to me only in Spanish, but he doesn't feel like explaining all the time.

T.

120V line-to-neutral x sqrt3 = 120 x 1.732 = 208V line-to-line. This would be for a 3-phase, 208-V, wye-connected xfmr.

Single-phase induction motors are often rated 230/208V. At 208V, a motor will draw more amps than at 230V.

:The three phases are all 120 volt phases so any phase to neutral is 120 volts, but since they are 120 degrees out of phase with each other the voltage is only 208 phase to phase. I think that anything that runs on 220/240 will probably run on 208.
:Will