1-1
a. General Description. The Basler BE3-25A Auto-Synchronizer provides automatic
synchronization of an oncoming generator with a bus or another generator. The Synchronizer
supplies correction signals to the oncoming generator to match it to the bus or to another generator
for frequency, phase angle, and voltage before being closed into the circuit. Options allow for dead
bus closing and a variety of output configurations for frequency/phase matching and voltage
matching. Construction consists of a case enclosed circuit board with external terminal connections.
A TEST/OPERATE switch, LED SYNC and POWER indicators and all operational adjustments are
located on the front panel or are accessible through access holes in the front panel.
b. Basic Unit Description.
(1) The basic BE3-25A Auto-Synchronizer monitors both the oncoming generator and bus
voltages then permits synchronizing the generator to an energized station bus or to another genera-
tor when the following predetermined conditions are satisfied:
(a) The frequency of the oncoming generator and the bus are matched to within ±0.1 Hertz.
This corresponds to a slip frequency of ±0.1 Hertz or less.
(b) The phase angle between the oncoming generator voltage and the bus voltage is less
than or equal to the allowable limit determined by the front panel setting. This limit is
established by the position of the front panel BREAKER CLOSING ANGLE switch with
settings of
±5
°
,
±10
°
,
±15
°
, and
±20
°
.
(c) The difference between the generator and bus voltage is less than the selected voltage
difference setting which is continuously adjustable over the range of ±5% to ±15% of the
bus voltage.
(2) When a jumper is connected across the 0.75 Second Time Delay terminals of the Synchro-
nizer (terminals D1 and D2), the generator will be synchronized only when the generator output
voltage is within the selected voltage difference setting and the measured phase angle and differ-
ence (slip) frequency are less than the following:
Phase Angle
Setting
Max. Slip
Frequency
±5
°
±0.037 Hz
±10
°
±0.074 Hz
±15
°
±0.1 Hz
±20
°
±0.1 Hz
(3) When the phase angle, frequency, and voltage are within predetermined limits, the Synchro-
nizer energizes the isolated synchronizing output relay to initiate generator circuit breaker closure.
The front panel SYNC indicator will illuminate and the frequency and phase angle correction signals
are automatically reset. The correction signals can be reset manually by connecting a normally open
contact between the Reset terminals of the Synchronizer (terminals R1 and R2). Closure of the
synchronizing output relay within the synchronizing parameters will automatically reset the correction
output signals.
SECTION 1
GENERAL INFORMATION
1-1. DESCRIPTION
