Hi Guest!
Hey - did you know if you click on the title of a thread it will take you to the first unread post since you last visited that thread?
but were afraid to ask: 
STOP!! Never post your email address in open forums. Bots can "harvest" your email! If you must share your email use a Private Message or use the 
smilie in place of the real @
Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
Offline
Hi Alec,
My apologies to you. You are entirely correct. The moving iron meter has no shunt. Relying instead on a few turns of heavy wire in the fixed coil. Below is a quote on the operation of this type of "ammeter". See attached drawing. A bit crude, but cheap & sufficient for the rather inacurate needs of the cars. My apologies to you & thanks for your persistence.
Regards,
D
----------------------------
"Moving Iron Vane Movement
The moving iron vane movement (Figure 3) can be used to measure both AC current and voltage. By changing the meter scale calibration, the movement can be used to measure DC current and voltage. The moving iron vane meter operates on the principle of magnetic repulsion between like poles. The measured current flows through a field coil which produces a magnetic field proportional to the magnitude of current. Suspended in this field are two iron vanes attached to a pointer. The two iron vanes consist of one fixed and one moveable vane. The magnetic field produced by the current flow magnetizes the two iron vanes with the same polarity regardless of the direction of current through the coil. Since like poles repel one another, the moving iron vane pulls away from the fixed vane and moves the meter pointer. This motion exerts a force against a spring. The distance the moving iron vane will travel against the spring depends on the strength of the magnetic field. The strength of the magnetic field depends on the magnitude of current flow."
--------------------------
My apologies to you. You are entirely correct. The moving iron meter has no shunt. Relying instead on a few turns of heavy wire in the fixed coil. Below is a quote on the operation of this type of "ammeter". See attached drawing. A bit crude, but cheap & sufficient for the rather inacurate needs of the cars. My apologies to you & thanks for your persistence.
Regards,
D
----------------------------
"Moving Iron Vane Movement
The moving iron vane movement (Figure 3) can be used to measure both AC current and voltage. By changing the meter scale calibration, the movement can be used to measure DC current and voltage. The moving iron vane meter operates on the principle of magnetic repulsion between like poles. The measured current flows through a field coil which produces a magnetic field proportional to the magnitude of current. Suspended in this field are two iron vanes attached to a pointer. The two iron vanes consist of one fixed and one moveable vane. The magnetic field produced by the current flow magnetizes the two iron vanes with the same polarity regardless of the direction of current through the coil. Since like poles repel one another, the moving iron vane pulls away from the fixed vane and moves the meter pointer. This motion exerts a force against a spring. The distance the moving iron vane will travel against the spring depends on the strength of the magnetic field. The strength of the magnetic field depends on the magnitude of current flow."
--------------------------
