# Automatic Voltage Regulator (AVR) AS440

- Page: https://sigmanortec.ro/en/automatic-voltage-regulator-avr-as440
- Price: 266.78 RON
- Availability: Out of stock
- Reference: 88209 · EAN: 5943559888475
- Category: Electronic components > Other Tension Modules > Voltage Regulators
- Package (shipping data): 0.32 kg
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 05:45 (Europe/Bucharest)

## Description

Automatic voltage regulator for brushless synchronous generators, maintains voltage stability in industrial applications with ±1% accuracy. Compatible with 100-130 VAC or 190-264 VAC sensing at 50/60 Hz, provides excitation up to 82 VDC with 4 A continuous and 7.5 A peak, includes underfrequency and excitation overload protection, and allows external adjustment and droop for parallel operation.
The AVR (Automatic Voltage Regulator) module from the AS440 series is designed for automatic output voltage regulation on brushless synchronous generators. The AVR ensures voltage regulation within ±1% and includes under-frequency protection (UFRO) and support for parallel operation.
Specifications:
Sensing (voltage detection): 100–130 VAC or 190–264 VAC, single phase, selectable by jumper, frequency 50/60 Hz
Power supply: 100–264 VAC, single phase, 50/60 Hz
Excitation output: 82 VDC @ 200 VAC, continuous current 4 A (max 7.5 A for 10 s)
Minimum field coil resistance: 15 Ω (10 Ω at input voltage < 175 VAC)
Regulation accuracy: ±1% (with 4% motor adjustment)
External voltage adjustment: 1 kΩ potentiometer, ±10% (increasing resistance decreases the voltage)
Under-frequency protection (UFRO): adjustable, threshold 94–98% of nominal frequency, selectable 50/60 Hz
Excitation overload protection: triggers at 65 VDC, timing 10–15 s
Droop input (parallel operation): 10 Ω, sensitivity 0.07 A for 5% droop
Analog input: ±5 VDC max, input resistance 1 kΩ
Operating temperature: -40 ~ 70°C
Mounting: panel, with screws
Dimensions: 100 x 135 mm
Weight: 250g
Layout:
Terminal
Marking
Description
S1, S2
SENSING
Voltage input (100–130V / 190–264V)
A1, A2
POWER
Excitation power supply
F1, F2
FIELD
Excitation output to the field coil
Z1, Z2
DROOP
Current transformer input for parallel operation
7, 8, Z2
LINK
For normal operation, connection between 8 and Z2
TRIM
Terminals for external adjustment potentiometer (1 kΩ)
STAB Switch
A-B-C-D
Stabilization response selection depending on generator power
Potentiometers
—
Adjustments: VOLTS, STABILITY, UFRO, DROOP, VTRIM, EXC TRIP
Stabilization configuration table
No.
Power range
Response
B-D
< 100 kW
Slow
A-C
< 100 kW
Fast
B-C
100–550 kW
Fast
A-B
\> 550 kW
Fast
Potentiometer table
Name
Function
Direction
VOLTS
Generator output voltage adjustment
Clockwise increases output voltage
STABILITY
Prevents voltage oscillations
Clockwise increases damping effect
STAB SWITCH
Optimizes transient performance
See the table above
UFRO
Sets the UFRO inflection point
Clockwise lowers the frequency of the point
DROOP
Sets generator droop (up to 5%)
Clockwise increases droop
VTRIM
Optimizes analog input sensitivity
Clockwise increases gain/sensitivity
EXC TRIP
Sets excitation overcurrent trip threshold
Clockwise increases trip level
Usage:
Connection: Mount the AVR in the generator panel, away from heat sources. Connect terminals S1 and S2 to the generator output voltage (single phase or between two phases, according to the configuration). Power supply (A1, A2) should be connected to the same source.
Output: Connect terminals F1 and F2 to the rotor field coil (via slip rings or exciter). Observe polarity (F1 positive, F2 negative) for correct operation.
Initial setup: Set the sensing voltage selection jumper (100-130V or 190-264V) and frequency (50/60 Hz). For normal operation, ensure the connection between terminals 8 and Z2 (link). If using an external trimmer, connect it to the TRIM terminals (1 kΩ).
Voltage and stability adjustment: Start the generator at nominal speed. Adjust the VOLTS potentiometer until the voltage reaches the desired value. Adjust STABILITY (by selecting position A-B-C-D according to generator power and then fine-tuning with the potentiometer) until the voltage is stable without oscillations.
Under-frequency protection adjustment (UFRO): Set the UFRO potentiometer to determine the start point of voltage reduction when speed decreases (usually 94-98% of nominal frequency). The correct value ensures that voltage decreases proportionally below nominal speed.
Parallel operation: For generators running in parallel, connect current transformers to terminals Z1 and Z2 and adjust the DROOP potentiometer to achieve 5% droop at zero power factor (0 PF).
Overload protection: If prolonged excitation overload occurs (e.g., short circuit), the EXC TRIP circuit will interrupt after 10-15 seconds. The trip threshold can be adjusted (factory set at 65 VDC).
Attention!
Do not exceed the specified maximum input voltage for sensing and power supply.
Ensure that the field coil resistance is ≥15 Ω (or ≥10 Ω at input voltage below 175 VAC).
If using the analog input, the connected device must be fully galvanically isolated from ground, with an insulation resistance of at least 500 VAC.
If the AVR is mounted in a vertical (portrait) position, the continuous output current must be reduced by 12%.