AvK Voltage Regulators

AvK Voltage Regulator COSIMAT N+

One particular advantage of AvK Automatic Voltage Regulators (AVR) is the variety of regulating features which is unachieved by other manufacturers.

The basic design of the voltage regulator COSIMAT N+ meets all usual requirements such as:

• High voltage accuracy under all operating conditions
• Stable operating performance during parallel operation
• Underspeed protection

> COS phi regulator
> QPF A Reactive power regulator with single-phase measurement
> QPF cos phi trimmer
> QPF C Reactive power regulator with single-phase measurement
> SB2 Automatic stand-by switchover
> TF/TF1 RC - low-pass filter
> ES Extended adjustment range
> UF U/f characteristic module
> UF U/f characteristic module with extension
> SR2 Current limitation
> EI External actual value detection
> UDC2 Detection of DC voltage actual value
> KP Cable compensation
> ER1 Controlling exciter current limiter

> AvK VOLTAGE REGULATOR COSIMAT C2

COS
cos phi regulator

FUNCTION: The power factor (cos phi) is held constant irrespective of fluctuations in system voltage or load changes.

APPLICATION: Parallel operation with fluctuating mains. Limitation of the excitation current by means of ER1 additional module.

QPF
Reactive power regulator with single-phase measurement

FUNCTION: The reactive power is held constant irrespective of fluctuations in system voltage or load changes.

APPLICATION: Parallel operation with constant reactive power output.

QPF
cos phi trimmer

FUNCTION: The power factor of the regulated alternator is the same as that of the total current or of the currents of the other generators (depending on current transformer connecti-on).

APPLICATION: Parallel operation with generators without linear voltage droop.

QPF
Reactive power trimmer with single-phase measurement

FUNCTION: The reactive power of the regulated alternator is the same as that of the other alternator.

APPLICATION: Parallel operation with generators without linear voltage droop.

SB2
Automatic stand-by switchover
(see 5.1 Stand-by and emergency manual switchover)

FUNCTION: Automatic switchover to the stand-by regulator in the event of regulator faults.

APPLICATION: Requirement for higher availability and ope-rating reliability (e.g. on ships).

TF/TF1
RC –150; low-pass filter
(Type TF1-50 for 50/60 Hz)

FUNCTION: Reducing the ripple effect in the voltage sensing signal of the "COSIMAT N+".

APPLICATION: Non-linear alternator loading by rectifier bridges or static converters.

ES
Extended adjustment range
(incl. 10 x potentiometer)

FUNCTION: External adjusting range from remanence to nominal voltage.

APPLICATION: Various test applications in the construction of transformers and electrical machines, run-up of large electric motors (pump motor).

UF
U/f characteristic module

FUNCTION: Frequency-dependent regulation of the alterna-tor voltage in accordance with a linear function. Different gradients can be selected.

APPLICATION: Variable-frequency operation of shaft alterna-tors on ships. Reduces the speed dip when there is a jump in the active load.

UF3
U/f characteristic module with extension

FUNCTION: Frequency-dependent control of the alternator voltage in accordance with freely selectable function. Operation with controlled inner field voltage down to 0 Hz.

APPLICATION: Control of the alternator voltage as a function of any measured variable (using standardised measured-value signal) and freely selectable characteristics. Used for driving asynchronous winding motors and for testing transformers.

SR2
Current limitation

FUNCTION: Limitation of alternator current to predetermined value.

APPLICATION: Run-up of large electric motors. Note: No effect on the switch-on peak in the case of direct
switch-on of motors or transformers.
or driving asynchronous winding motors and for testing transformers.

EI
External actual value detection

FUNCTION: Regulation to externally measured voltage. If the measuring lead breaks, it switches over to voltage measurement at the alternator terminal.

APPLICATION: Providing the consumer with highly accurate voltages over long input leads.

UDC2
Detection of DC voltage actual value

FUNCTION: Electrically isolated measurement of a DC voltage actual value.

APPLICATION: Voltage regulation of a synchronous alternator to the rectification value of an output-side bridge-type rectifier.

KP
Cable compensation

FUNCTION: Raising the alternator voltage as a function of the current.

APPLICATION: Compensation of cable voltage losses by way of the load current, specifically when there is no possibility of access to the external measuring point.

ER1
Controlling exciter current limiter

FUNCTION: Secondary regulation of the exciter current to a selected over- and under-excitation value.

APPLICATION: Protects the alternator in cos phi-regulated parallel operation with a "soft" mains when using "COSIMAT N+" and COS module.
When used with QPF, controlling limitation of the exciter current cannot be used. In that case, it would be necessary to employ contact indication in the event of the exciter current limits being over- or undershot.

AVK Voltage Regulator COSIMAT C2

The "COSIMAT C2" is a compact voltage regulator designed to control synchronous alternator.

The "COSIMAT C2" permits two different ways of influencing the alternator voltage, according to alternator frequency (U/f function and underspeed protection).

The principal features of the "COSIMAT C2" are:

• Internal and external alternator voltage setpoint adjustment.
• PID control exciter.
• Proportional change in alternator voltage in accordance with frequency (U/f operation).
• Disproportionately severe drop in alternator voltage when operating at underfrequency or underspeed (underspeed protection).
• Resistant to environmental effects thanks to lacquer - impregnated circuit boards.
• High- value components for long service life.
• Extended adjustment range for alternator voltage.