Winco AS440 User Manual

AS440 AUTOMATIC VOLTAGE

REGULATOR (AVR)

SPECIFICATION INSTALLATION AND ADJUSTMENTS

General description

AS440 is a half wave phase controlled thyristor type AVR and forms part of the excitation system for a brushless generator. The design employs Surface Mount Technology (SMT) for high integration of features in a small footprint AVR.

Positive voltage build up from residual levels is ensured by the use of efficient semiconductors in the power circuitry of the AVR. The power and voltage sensing circuits have separate terminals, allowing the excitation power to be derived directly from the stator winding for basic applications or from an auxiliary winding if sustained short circuit performance is required.

The AVR is linked with the main stator windings and the exciter field windings to provide closed loop control of the output voltage with load regulation of +/- 1.0%.

The AVR voltage sensing terminals continuously sample the output windings for voltage control purposes. In response to this sample voltage, the AVR controls the power fed to the exciter field, and hence the main field, to maintain the machine output voltage within the specified limits, compensating for load, speed, temperature and power factor, of the generator.

A frequency measuring circuit continually monitors the generator output and provides under-speed protection of the excitation system, by reducing the output voltage proportionally with speed below a pre-settable threshold. A manual adjustment is provided for factory setting of the under frequency roll off point, (UFRO). This can easily be changed to 50 or 60 Hz in the field by push-on link selection.

Over excitation conditions are limited to a safe period by a protection circuit within the AVR.

Provision is made for the connection of a remote voltage trimmer, allowing the user fine control of the generator's output.

An analogue input is provided allowing connection to the Power Factor controller or other external devices with compatible output.

The AVR has the facility for droop CT connection, to allow parallel running with other similarly equipped generators.

Technical specification

SENSING INPUT

Voltage Jumper selectable 100-130 Vac 1 phase or 190-264 Vac 1 phase Frequency 50-60 Hz nominal

POWER INPUT Voltage 100-264 V ac 1 phase

Frequency 50-60 Hz nominal

OUTPUT

Voltage 82 V d.c. @ 200 V a.c. Current continuous 4A (see note 1). transient 7.5A for 10 secs. Resistance 15 ohms min (10 ohms min when input volts is less than 175 ac)

REGULATION +/- 1.0% (see note 2) THERMAL DRIFT

0.03% per deg. C change in AVR ambient (see note 3)

TYPICAL SYSTEM RESPONSE AVR response 20 ms Filed current to 90% 80 ms

Machine Volts to 97% 300 ms

EXTERNAL VOLTAGE ADJUSTMENT +/-10% with 1 k ohm 1 watt trimmer (see note 4)

Increasing resistance lowers voltage.

UNDER FREQUENCY PROTECTION Set point 94 -98% Hz (see note 5) UNIT POWER DISSIPATION 12 watts maximum BUILD UP VOLTAGE 4 Volts @ AVR terminals ANALOGUE INPUT Maximum input +/- 5 Vdc (see note 6)

Sensitivity 1V for 5% Generator Volts (adjustable) Input resistance 1k ohm

QUADRATURE DROOP INPUT

10 ohms burden Max. sensitivity: 0.07 A for 5% droop 0PF Max. input: 0.33 A

OVER EXCITATION PROTECTION Set point 65 V dc

Time delay 10-15 seconds (fixed)

ENVIRONMENTAL Vibration 20-100 Hz 50mm/sec

100Hz – 2kHz 3.3g Operating temperature -40 to +70C (note 7) Relative Humidity 0-70C 95% (note 8) Storage temperature -55 to +80C

NOTES

1. De-rate by 12% if mounted in ‘portrait’ orientation.

2. With 4% engine governing.

3. After 2 minutes.

4. Generator de-rate may apply. Check with factory.

5. Factory set, semi-sealed, jumper selectable.

6. Any device connected to the analogue input must be fully floating (galvanically isolated from ground), with an insulation strength of 500V ac.

7. De-rate output current by 5% per degree C above 60C.

8. Non condensing.

pply

DESIGN DETAIL

Voltage

Sensing

Generator

Droop Hand

Trimmer

Analogue

Input

The main functions of the AVR are: Potential Divider and Rectifier

generator output voltage and attenuates it. The potential divider is adjustable by the AVR Volts potentiometer and external hand trimmer (when fitted). The output from the droop CT is also added to this signal. A rectifier converts the a.c. input signal into d.c. for further processing.

The DC Mixer signal.

The Amplifier Reference Voltage provide a controlling signal for the power devices. The Ramp Generator control the conduction period of the Power Control Devices and hence provides the excitation system with the required power to maintain the generator voltage within specified limits.

The Stability Circuit feedback to ensure good steady state and transient performance of the control system.

The Low Hz Detector electrical cycle and causes the reference voltage to be reduced approximately linearly with speed below a presettable threshold. A Light Emitting Diode gives indication of underspeed running.

adds the Analogue input signal the Sensing

(Amp) compares the sensing voltage to the

Potential

Divider &

Rectifier

Low Hz

Detection

Reference

Volta

Mixe

takes a proportion of the

and amplifies the difference (error) to

and Level Detector and Driver infinitely

provides adjustable negative ac

measures the period of each

Amp

Stability

Circuit

Suppression

Synchronising

Circuit

Short circuit

Detecto

Ramp

Generato

The Synchronising circuit is used to keep the Ramp Generator and Low Hz Detector locked to the generator waveform period.

The Low Pass Filter affecting the operation of the AVR control circuit.

The Short Circuit Detector short circuit on the generator output and forces the Power Control Devices occurs when the AVR is powered from an auxiliary winding.

Power Control Devices current in response to the error signal produced by the Amplifier.

Suppression cycle voltage spikes damaging the AVR components and also to reduce the amount of conducted noise on the generator terminals.

The Over Excitation Detector exciter field voltage and provides signals, to collapse the output voltage if an over excitation condition persists for the specified time period.

The Power Supply the AVR circuitry.

Low Pass

Filte

Power su

Level

Detector &

Driver

Over

excitation

detector

prevents distorted waveforms

senses the presence of a

into full conduction. This only

vary the amount of exciter field

components are included to prevent sub

continuously monitors the

provides the required voltages for

Power

Control

Devices

Exciter

Field

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