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> New cummins stamford AS440 age voltage regulator avr
New cummins stamford AS440 age voltage regulator avr
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
Positive voltage build up from residual levels is ensured by
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.
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
Over excitation conditions are limited to a safe period by a
protection circuit within the AVR.
An analogue input is provided allowing connection to the
Power Factor controller or other external devices with
Voltage 82 V d.c. @ 200 V a.c.
Current continuous 4A (see note 1).
0.03% per deg. C change in AVR ambient (see note 3)
+/-10% with 1 k ohm 1 watt trimmer (see note 4)
Increasing resistance lowers voltage.
Set point 94 -98% Hz (see note 5)
Max. sensitivity: 0.07 A for 5% droop 0PF
Time delay 10-15 seconds (fixed)
Operating temperature -40 to +70C (note 7)
Relative Humidity 0-70C 95% (note 8)
