Kutai electronics EA341 Operation Manual

KUTAI ELECTRONICS INDUSTRY CO., LTD.

TEL : [phone] FAX : [phone] Website : www.kutai.com.tw
Headquarters : No.3, Ln. 201, Qianfu St., Qianzhen Dist., Kaohsiung City 80664, Taiwan

Self Excited Automatic Voltage Regulator

Compatible with Newage MX341*

* All manufacturer names and numbers are used for reference purpose only

and do not imply that any part is the product of these manufacturer.

EA341

Generator Automatic Voltage Regulator

Operation Manual

Sensing Input

Quadrature Droop Input

Voltage 190  264 Vac Max, 1 phase 2 wire

Burden 10 ohms

Frequency 50/60 Hz, selectable

Max. input 0.33 A

Max. sensitivity 0.07 A for 5% droop (PF = 0)

Power Input (PMG)

Voltage 170  220 Vac Max, 3 phase 3 wire

Over Voltage Detector Input

Current 3A / Phase

Set point 300V. Time delay 1 sec (fixed)

Frequency 100  120 Hz, nominal

CB trip coil volt 10  30 Vdc / 0.5 Amp

CB trip coil resistance 20  60 ohms

Excitation Output

Voltage Max. 120 Vdc @ power input 220 Vac

Current Limit Input

Current Continuous 2.7A

Burden 10 ohms

Intermittent 6A for 10 secs.

Sensitivity range 0.5  1A

Resistance Min. 15 ohm

Under Frequency Protection (Factory Presets)

External Voltage Adjustment

Set point 95% Hz

Max. +/- 10% @ 1K ohm 1 watt potentiometer

Slope 170% down to 30 Hz

Voltage Regulation

Over Excitation Protection

Less than +/- 1% ( with 4% engine governing )

Set point 90 Vdc

Time delay 10 secs. (fixed)

Build Up Voltage

5 Vac residual volts at power input terminal

Voltage Thermal Drift

Less than 3% at temperature range -40 to +70 ˚C

Soft Start Ramp Time

2 seconds +/- 10%

Environment

Operating Temperature -40 to +70 ˚C

Static Power Dissipation

Storage Temperature -40 to +85 ˚C

Max.12 watts

Relative Humidity Max. 95%

Vibration 3.3 Gs @ 100  2K Hz

Analogue Voltage Input

Input Resistance 1K ohm

Dimensions

Max. Input +/- 5 Vdc

150.0 (L) x 135.0 (W) x 48.0 (H) mm

Sensitivity 1V for 5% generator volt

Weight

394 g +/- 2%

SECTION 1 : SPECIFICATION

SECTION 2 : GENERAL DESCRIPTION

2.1 EA341 is a two phase sensed Automatic Voltage
Regulator and forms part of the excitation system
for a brush-less generator. Excitation power is
derived from a three-phase permanent magnet
generator (PMG), to isolate the AVR control
circuits from the effects of nonlinear loads and to
reduce radio frequency interference on the
generator terminals. Sustained generator short
circuit current is another feature of the PMG
system.

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2 EA341

2.2 The AVR senses the voltage in the main
generator winding and controls the power fed to
the exciter stator and hence the main rotor to
maintain the generator output voltage within the
specified limits, compensating for load, speed,
temperature and power factor of the generator.

2.3 Soft start circuitry is included to provide a smooth
controlled build up of generator output voltage.

CONTROL

FUNCTION

DIRECTION

VOLT

To adjust generator output voltage

Clockwise increases output voltage

STABILITY

To prevent voltage hunting

Clockwise increase the damping effect

UFRO

To set the UFRO knee point

Clockwise reduces the knee point frequency

DROOP

To set the generator droop to 5% at 0 pf

Clockwise increases the droop

TRIM

To optimize analogue input sensitivity

Clockwise increases the gain or sensitivity

EXC

To set the over excitation cut off level

Clockwise increase the cut off level

DIP

To set the frequency related voltage dip

Clockwise increases the voltage dip

2.4 A frequency measuring circuit continually
monitors the shaft speed of the generator and
provides under-speed protection of the excitation
system by reducing the generator output voltage
proportionally with speed below a pre-settable
threshold. A further enhancement of this feature
is an adjustable VOLT per Hertz slope to improve
engine recovery time on turbo charged engines.
Soft start circuitry is included to provide a smooth
controlled build up of generator output voltage.

2.5 Uncontrolled excitation is limited to a safe period
by internal shutdown of the AVR output device.
This condition remains latched until the generator
has stopped.

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

2.7 An analogue input is provided allowing
connection to a controller or other external
devices with compatible output.

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

NOTE :

(1) Derate linearly from 3.7A at 50 ˚C to 2.7A at 70 ˚C.
(2) The stated voltage regulation may not be

maintained in the presence of certain transmitted
radio signals. Any change in regulation will fall
within the limits in Criteria B of S.EN.61000-6-2 :

2001.
(3) After 10 minutes.
(4) Applies to Mod status E onwards. Generator

de-rate may apply. Check with factory. Factory set,
semi-sealed, jumper selectable.

(5) Any device connected to the analogue input must

be fully looting (galvanically isolated from ground),
with an insulation strength of 500 Vac.

(6) Non condensing.

SECTION 3 : SUMMARY OF AVR CONTROLS

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EA341 3

WARNING

Do not increase the voltage above the rated
generator voltage. If in doubt, refer to the rating
plate mounted on the generator case.

Do not ground any of the hand trimmer terminals,
as these could be above earth potential. Failure
to observe this could cause equipment damage.

WARNING

Any devices connected to this input must be fully
floating and galvanically isolated from ground,
with an insulation capability of 500 Vac. Failure to
observe this could result in equipment damage.

SECTION 4 : ADJUSTMENT OF AVR
CONTROLS

4.1 Voltage Adjustment

4.1.1 The generator output voltage is set at the factory,
but can be altered by careful adjustment of the
VOLT control on the AVR board, or by the
external hand trimmer if fitted.

Terminals J1 and J2 on the AVR will be fitted with

a shorting link if no hand trimmer is required.

4.1.2 If a replacement AVR has been fitted or re-setting
of the VOLT adjustment is required, proceed as
follows :

(1) Before running generator, turn the VOLT

control fully anti-clockwise.

(2) Turn remote VOLT trimmer (if fitted) to

midway position.
(3) Turn STABILITY control to midway position.
(4) Connect a suitable voltmeter (0  300 Vac)

across line to neutral of the generator.
(5) Start generator set, and run on no load at

nominal frequency e.g. 50  53 Hz or 60  63

Hz.
(6) If the red Light Emitting Diode (LED) is

illuminated, refer to the Under Frequency Roll

Off (UFRO) adjustment.
(7) Carefully turn VOLT control clockwise until

rated voltage is reached.
(8) If instability is present at rated voltage, refer to

stability adjustment, then re-adjust voltage if

necessary.
(9) Voltage adjustment is now completed.

4.2 Stability Adjustment

4.2.1 The AVR includes stability or damping circuit to
provide good steady state and transient
performance of the generator.

4.2.2 A jumper link selector is provided to optimize the
response of the stability circuit to various size
generators.

4.2.3 The link should be positioned as shown in the
diagram according to the kw rating of the
generator. The correct setting of the Stability
adjustment can be found by running the
generator at no load and slowly turning the

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4 EA341

stability control anti-clockwise until the generator
voltage starts to become unstable. The optimum
or critically damped position is slightly clockwise
from this point (i.e. where the machine VOLT are
stable but close to the unstable region).

4.3 Under Frequency Roll Off (UFRO) Adjustment

4.3.1 The AVR incorporates an under-speed protection
circuit which gives a VOLT / Hz characteristic
when the generator speed falls below a
presentable threshold known as the “knee” point.
The red Light Emitting Diode (LED) gives
indication that the UFRO circuit is operating.

4.3.2 The UFRO adjustment is preset and sealed and
only requires the selection of 50 or 60 Hz and 4
pole or 6 pole, using the jumper link as shown in
the diagram. For optimum setting, the LED
should illuminate as the frequency falls just below
nominal, i.e. 45 Hz on a 50 Hz system or 55 Hz
on a 60 Hz system.

4.4 DROOP Adjustment

Generators intended for parallel operation are fitted
with a quadrature droop C.T. which provides a power
factor dependent signal for the AVR. The C.T. is
connected to S1, S2 on the AVR, (see generator wiring
diagram for details). The DROOP adjustment is
normally preset in the works to give 5% voltage droop
at full load zero power factors. Clockwise increases the
amount of C.T. signal injected into the AVR and
increases the droop with lagging power factor (cos Ø ).
With the control fully anti-clockwise there is no droop.

4.5 Trim Adjustment

4.5.1 An analogue input (A1, A2) is provided to connect
to the controller or other devices. It is designed to
accept dc signals up to +/- 5 VOLT.

4.5.2 The dc signal applied to this input adds to the
AVR sensing circuit. A1 is connected to the AVR 0
VOLT. Positive on A2 increases excitation.
Negative on A2 decreases excitation.

4.5.3 The TRIM control allows the user to adjust the
sensitivity of the input. With TRIM fully
anti-clockwise the externally applied signal has
no effect. Clockwise it has maximum effect.

4.5.4 Normal setting is fully clockwise when used with a
controller.

WARNING

Please make sure you have read and understand
the contents of the instruction manual prior to
installation. Incorrect wiring connection may
result in irreversible damage to the product and
other equipments.

ATTENTION

1. AVR can be mounted directly on the engine, genset, switchgear, control panel, or any position that will
not affects operation. For dimension reference, please see Figure 1.

2. All voltage readings are to be taken with an average-reading voltmeter Meggers and high-potential test
equipment must not be used. Use of such equipment could damage the AVR.

3. Improper setting of under-frequency protection could cause the output voltage of the unit to drop or
become unstable under with changes in load. Avoid making any changes to the U/F setting unless
necessary.

4. Set the O/E potemtiometer at max. position when paralleling.

Figure 1 Outline Drawing

DIP

EXC. TRIP

STABILITY

DROOP

TRIM

VOLT

UFRO

LED

C B A

C-A < 90KW
C-B < 90-550KW
B-A < 550KW

115.0

135.0

130.0

150.0

48.0

21.5

5.5

4.6 Excitation (EXC) Adjustment

This adjustment is set and sealed in the works and
should not be tampered with. An over excitation
condition is indicated by the illumination of the red LED
which also indicates under-speed running and

With the DIP control fully anti-clockwise, the generator
voltage will follow the normal V/Hz line as the speed
falls below nominal. Turning the DIP control clockwise

provides greater voltage roll off aiding engine recovery.
over-volt.
The generator must be stopped to reset an

over-excitation trip.

4.7 DIP Adjustment

This feature is mostly used when the generator is
coupled to turbo charged engines with limited block
load acceptance. The feature works by increasing the
V/Hz slope to give greater voltage roll off in proportion
to speed.

SECTION 5 : FITTING AND OPERATING (Refer to generator wiring diagram for connection
details)

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EA341 5

Exciter

Generator

3Ø Bridge

EA341

EXC. TRIP

SELECTION

DROOP

TRIM

VOLTS

UFRO

C-B 90-550KW
B-A > 550KW

A1
A2
S1
S2

J1
J2
J3
J4
J5
J6
J7
J8

K2 K1 P2

P3

P4 XX X

3

2 2 1

FREQUENCY

SENSING SELECTION

INDICATOR

C B A

3

2 1

STABILITY

DIP

LED

SELECTION

k1-k2 linked for
normal operation.

3-1 4P/60HZ
3-2 4P/50HZ
2-1 6P/50HZ
NO LINK 6P/50HZ

C-A < 90KW

EA341

~

G

Generator

P4

P3

P2

PMG

XXX

3 Bridge

T

220V

S

R

S1

C.T

S2

12

For external adjusted

1K

2

3

Exciter

Figure 2 Disposition Drawing

Figure 3 Wiring Drawing

Note : When the system voltage over 220 Vac, a transformer is necessary at

sensing input terminal is recommend.

※

Appearance and specifications of products are subject to change for improvement without prior notice.

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6 EA341