Magneto phone generates no ring voltage

[rambo1152]

Originally Posted by joebog1

we didnt have a phone as kids, but my Nanna did ( aka grandmah ) on a party line.

j.b.

Joe, I'll be disappointed if you and your mates didn't have SCR-536 handie talkies like "The Terrible Ten"

[petervk2mlg]

I took the magneto assembly apart. Here are some pics. I'm unsure of the correct names for the various parts.

[FrankB]

One can put a NE2 bulb between the wires of f the generator and it should light if there is voltage. IIRC they strike between 60v and 90V. I have used old military field phone gennys to light the bulbs up.
The phone PS I have generate 90V for the ringer line.(likely less by the time it reaches the house).
I was rewiring the house phone lines and someone rang in. It was a pretty good jolt, as I was holding the lines at the time.

[joebog1]

Roger Ramjet,
NO !! it wasnt fence lines, but a single THICK copper wire. From memory ( and I am talking of my memory 60 years ago ) It was hard drawn copper about 1/8" thick
( 3mm in todays dollars, near enough ) Single insulator and not very high above the ground. Perhaps ten foot at the droop point.
The same phone line STILL exists!!!, and I have always wondered why some idiot hasnt pinched the copper wire!!. I would show pics except I moved to the next village 3000 kilometres by road north, so I cant take pics today.

Joe

[joebog1]

Peter in Parkes,
That armature doent look in very exciting condition !!.
It may be black enamel ( which in itself is a disaster ), but it could be cooked.
It is VERY black!!.
UNless you have the patience of Jobe, rewinding is out of order.

Joe

[Roger Ramjet]

Yes the coil does look cooked but I wonder how that could happen even if the output was overloaded. Could it be an incoming lightning strike on the line ? Clearly, the magneto is disconnected until turned - although a high transient voltage would make short work of that !
In any event the bell & capacitor would be first casualty. That said the bell capacitor did look a bit cooked also ?

Rog

[petervk2mlg]

I’m not too alarmed as I pulled apart a good working magneto to check its state.
Pics attached

[Roger Ramjet]

Good move Peter......cannot see clearly on your piccy's so does the coil on the working unit look similar the the blackened coil on the faulty one ?
Rog

[petervk2mlg]

I'll let you guys be the judge.

[petervk2mlg]

Originally Posted by Dave Moll

Modern equivalents would be 1.8μF and 0.47μF respecively.

Many thanks Dave.