The Automatic Voltage Regulator – AVR:
Guide and Comparison
The Operation, Application and Comparison of Automatic Voltages Regulators in AC Power Applications
7.3 Electronic Voltage Regulator Characteristics
Electronic voltage regulators are typically designed for indoor, low voltage applications and are air-cooled (i.e. using dry-type transformers instead of oil-filled). Other characteristics of tap switching and double conversion EVRs differ substantially so they are listed separately below:
Tap Switching Electronic Voltage Regulators
Size (kVA): |
3 VA up to 2,000 kVA |
Nominal Voltages: |
Common AC voltages - 120, 208, 240 & 480 at 60 Hz |
Input Voltage Range: |
+10% to -25% (varies by manufacturer) |
Output Regulation: |
+/-2% to +/-5% (varies by manufacturer) |
Phase: |
Single and three phase |
Voltage Step Up/Down: |
Yes |
Cooling Media: |
Air |
Location: |
Indoor |
Efficiency: |
Usually > 95% (see comment below) |
Double Conversion Electronic Voltage Regulators
Size (kVA): |
3 VA up to400 kVA |
Nominal Voltages: |
Common AC voltages - 120, 208, 240 & 480 at 60 Hz |
Input Voltage Range: |
+10% to -25% for tap switchers and+10% to -15% for UPS (varies by manufacturer) |
Output Regulation: |
+/-1% to +/-5% (varies by manufacturer) |
Phase: |
Single and three phase |
Voltage Step Up/Down: |
Yes |
Cooling Media: |
Air |
Location: |
Indoor |
Efficiency: |
Up to 95% (see comment below) |
Efficiency for a tap switching EVR is usually fairly flat across the load range from 10 to 100% of rated load. However, the efficiency for a double conversion EVR tends to drop quickly as the load drops below 100%. Other factors like ambient temperature, power factor, load type etc. can also negatively impact double conversion EVR efficiency.
Quick Links
1 The AC Automatic Voltage Regulator
2 Automatic Voltage Regulators and Power Conditioners
3 The Need for Automatic Voltage Regulation
4 Automatic Voltage Regulator Function
5 The Ferroresonant Transformer (Type) Voltage Regulator
6 The Mechanical (Type) Voltage Regulator
7 The Electronic (Type) Voltage Regulator
Complete Table of Contents...