Basler Electric AVC125-10 Voltage Regulator

Introduction

The AVC63-12 and AVC125-10 regulate the level of excitation supplied

to the field of a conventional, brushless, synchronous generator.

Regulation is achieved by sensing the generator output voltage, converting

it to a dc signal, and comparing the signal to a reference voltage.

An error signal is developed and used to control the dc field power in

order to maintain a constant generator output.

Each regulator includes frequency compensation with selectable slope,

inverse-time overexcitation shutdown, buildup circuitry, single-phase or

three-phase voltage sensing, single-phase or three-phase shunt or

permanent magnet generator (PMG) power input, parallel droop

compensation, and an accessory input. The accessory input provides

compatibility with devices such as var/power factor controllers or excitation

limiters.

Startup

Startup and troubleshooting procedures for the AVC63-12 and AVC125-10

are listed in the following procedure.

Symptoms of startup problems stemming from improper regulator adjustments

and certain generator system problems that resemble faulty regulation are

listed with possible solutions. Simplifying the system by eliminating components,

such as remote adjustment potentiometers and other nonessential items, can

be helpful in the troubleshooting process. Adjustments, options, and an operational

test are included in the paragraphs following the procedure.

1. Ensure that the regulator has been installed in accordance with the Installation

and Connections paragraphs before proceeding with system startup.

2. Start the prime mover and bring it up to rated speed.

If the voltage does not build up:

a. Flash the field.

b. Remove power for one minute to reset the overexcitation circuit.

3. Slowly adjust the VOLT potentiometer or external, voltage adjust rheostat until

the voltage reaches nominal.

If the voltage will not build up to rated:

Check the generator output for a shorted or excessive load.

4. Apply and remove the generator load to check stability.

If the generator response is too slow or is hunting (oscillating):

a. Check the generator output for a shorted or excessive load. Adjust the STB

potentiometer with no load applied.

b. Check stability of the governor.

5. Check regulation under normal operating conditions.

If the regulation is poor:

a. Check that the prime mover is up to rated speed.

b. Check that the voltmeter is connected at the same point as the regulator

sensing.

c. Use an average-sensing voltmeter (not an rms-sensing voltmeter).

6. Reduce the generator frequency. The generator output should decrease

from this point.

If the generator output voltage does not decrease at the desired frequency:

a. Check that all wiring is in accordance with the connection diagrams provided

in this instruction sheet.

Options

The AVC63-12 and AVC125-10 may be equipped with the following options to

enhance operation.

Remote Voltage Adjust

Connect a 10 kΩ, 2 W potentiometer across terminals 6a and 7. remove the

jumper from terminals 4 and 7. and adjust the front panel VLT ADJ control fully

clockwise to enable remote adjustment of the voltage setpoint.

Inrush Current Reduction Module

A Basler ICRM-15 is required when energizing the AVC63-12 or AVC125-10 from

a source that is already at the regulator input power rating.

The ICRM-15 minimizes the amount of inrush current that could be seen when

power is applied.

Excitation Disable

This option disables excitation by removing power from the regulator. A switch

removing voltage from terminals 26. 28 and/or 30 will remove regulator power.

Excitation Limiter

The Basler EL 200 provides an initial, fast-acting limit of the field current at a

user-defined level. Once the field current has changed to the selected level, the

EL 200 provides a signal to the regulator to change the excitation level.

External Bias Control

The accessory input enables adjustment of the regulation setpoint through

application of a bias signal from an external device. Any external device that

provides a bias signal within the range of ±3 Vdc may be used. Examples of

external biasing devices include var/power factor controllers, excitation limiters,