Stability; Limiting The Excitation Current Iex; Protection; Voltage Build-Up - Leroy-Somer R452 Installation And Maintenance Manual

LEROY-SOMER

1.3.9 - stability

Definition of stability potentiometers:
- P3: integrator
- P8: proportional
- P9: derivative
- Standard position potentiometer positions: 5
Setting the stability:
The stability is initially set on voltage build-up, with the
alternator at rated speed, de-energised.
At the start of the test, set all 3 potentiometers to 5.
Find the best position for P3:
Close the de-energisation contact and monitor the voltage
making (overvoltage and oscillation) on build-up.
De-energise the alternator (open the de-energisation contact).
Set P3 to a different position from 5 and repeat voltage build-up.
Repeat this test several times and select the position of P3
which produces the best voltage build-up, ie. without
overvoltage and without oscillations.
Retain this position for subsequent tests.
Find the best position for P8:
Perform the same tests as before.
Select the position of P8 which produces the best voltage build-up.
Retain this position for subsequent tests.
Find the best position for P9:
Perform the same tests as before.
Select the position of P9 which produces the best voltage build-up.
Then do a test with load impact (or load shedding) and
fine-tune the settings.

1.3.10 - limiting the excitation current iex

- Potentiometer P5 is used to adjust Iex limitation. Limitation
of the excitation current is active for 10s. After this period of
time, the excitation current is limited to 2A.
The maximum limitation is 15A.
The minimum limitation is when the potentiometer has been
rotated fully anti-clockwise.
In the absence of specification to the contrary, P5 is
positioned at the clockwise limit.
- Static adjustment of the max. excitation current.
For this value, the static adjustment is possible when the
alternator is stopped, which will not endanger the alternator or
the installation.
Disconnect power supply wires X1,X2 and Z1,Z2, and the
voltage reference from the alternator (terminal block J1).
Connect the mains power supply, 200 to 240V, as indicated
(X1 and X2): 0-220V). Install a 20A D.C. ammeter in series
with the exciter field.
Turn P5 fully anti-clockwise, switch on the power supply
(switch A).
If there is no output current from the AVR, turn potentiometer
P2 (voltage) clockwise until the ammeter indicates a
stabilised current.
Switch the power supply off and then on again, turn P5
clockwise until the required excitation current is reached
(limited to 15A), (for precise adjustment contact Leroy-Somer).
Checking the internal protection:
Open switch (D): the excitation current should increase to its
preset ceiling, remain at that level for 10s and then fall back
automatically to a value less than 2A.
8
INSTALLATION AND MAINTENANCE
VOLTAGE REGULATOR R452
P
RESENTATION OF THE
R 452
To reset, switch off the power supply by opening switch (A).
Note: After setting the excitation ceiling using this procedure,
re-adjust the voltage.
According to mains frequency
ST3
R 452
P5
50Hz 60Hz
P4
ST5
Max. excit.
ST2
P3
ST1
P2
P1
220V
S1 S2
Voltage
380V
ST4

1.3.11 - protection

There are two fuses in the power section. They are fitted
externally to the AVR but inside the alternator terminal box.
Rating: gG 10/38 16A 500V

1.3.12 - voltage build-up

The voltage build-up is automatic (no overvoltage) from the
residual magnetism.
If there is no voltage build-up, a short pulse of continuous
isolated voltage (12VDC), will usually remedy this. Otherwise,
proceed in accordance with the diagram below to re-establish
the residual magnetism:
X2
R 452
Z1
X1
Z2
E+
E-

1.3.13 - power usage

The power used by the R 449 is 30W, when the alternator is
at rated power.

1.3.14 - de-energising

The regulator is de-energised by switching off its power
supply.
Contact rating: 15A, 250V AC
X2
R 452
Z1
X1
Z2
E+
E-

1.4 - environment

- Operating temperature: -20 ˚C to +70 ˚C
- Storage temperature: -55 ˚C to +85 ˚C
- Shocks on the base: 9g for the 3 right-angled directions
- Vibrations: Less than 10Hz: 2mm half-peak amplitude
10Hz to 100Hz: 100mm/s
Above 100Hz: 8g
Ref. 3563 GB - 4.33 / a - 01.02
Mains
(Supply 50/60 Hz)
X2
Z1 A
X1
Exciter field
Z2
~ 10 ohms
E+
E-
- +
0V
A
20A CC / DC
D
(12V - 10A)
Isolated DC
t
power supply
~ 10 ohms
Exciter field
Aux. windings
+
-