Siemens AVR SY-AVR-2058B – Automatic Voltage Regulator

The Siemens AVR SY-AVR-2058B (EM-2058B) is a high-accuracy automatic voltage regulator designed for brushless and shunt-excited alternator systems (notably compatible with the 1FC2 series). It precisely controls excitation current to maintain stable output voltage under fluctuating loads and input conditions. Engineered for robust industrial use, the unit offers tight regulation, fast response and reliable protection for generator sets.

Key Specifications:

• Sensing Input: ~320-480 V AC (2-phase, 2-wire) for standard alternator sensing. 

• Power Input: ~184-276 V AC (1-phase) typical. 

• Output: Up to ~160 V DC for the excitation field. 

• Regulation Accuracy: ±0.5% typical. 

• Frequency: 50/60 Hz. 

• Designed For: Alternators in the Siemens 1FC2 series (and possibly similar frames) with OEM excitation control needs.