Side-by-side reference

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Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

Hz HzDouble frequency meter: original educational illustration
Symbols

Double frequency meter

A double frequency meter shows the frequency of the running system and the incoming machine on one instrument. During manual synchronising the operator adjusts the incoming governor until the two readings match closely, then uses the synchroscope for final phase alignment.

Drawing use
SLD / Schematic
Application
Metering & protection
Reference family
IEC / Manufacturer

A distinction that matters

A double frequency meter compares frequency; a synchroscope shows the phase difference and its rate of change.

Full reference
V VDouble voltmeter: original educational illustration
Symbols

Double voltmeter

A double voltmeter contains two voltage measuring elements, usually reading the running busbar and the incoming generator or feeder. Mounted on a synchronising panel next to the double frequency meter and synchroscope, it lets the operator match voltages before closing.

Drawing use
SLD / Schematic
Application
Metering & protection
Reference family
IEC / Manufacturer

A distinction that matters

A double voltmeter shows both voltages; a differential voltmeter shows only their difference.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.

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