Stamford AVRs for self-excited generators without short-circuit maintenance receive their power
direct from the generator output terminals, and control generator
output voltage through continual automatic adjustment of the
main rotor field strength.
SX460
The SX460 is the standard AVR offered
with generators in the lower power bands, achieving voltage
regulation in the order of ± 1.5 %. A feature of this (and
all Stamford AVR's) is that output voltage is reduced with
speed below the normal operating level, to assist the engine
or prime mover to recover after sudden application of a heavy
load. This is an ideal choice for applications where a generator
set is to be run in a stand-alone application where no specialist
requirements exist.
AS440
The AS440 has all the features of the
SX460, additionally achieving voltage regulation in the order
of ± 1.0 %.
A current transformer can be supplied with the SX440 to provide
quadrature voltage droop for parallel operation with other
generator sets, also a power factor control accessory can
be fitted. The AS440 will also work with an auxiliary winding
to support a short circuit and improve motor starting. A three
phase sensing unit can be added to the AS440 AVR control system.
The size of t his AVR is ideal for mounting in the terminal
boxes of the small (BC) Stamford generator ranges.