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6RA22 SIMOREG K converters for single-phase input are available in two types of construction. Units with housing are recommended for single-motor drives. Units without housing, installed in a sub-rack, provide a space-saving arrangement where two or more drives are to be combined to form a unit.

Функции

Functions of the open-loop and closed-loop control for converters in B2HK and B6C connections

Ramp-function generator

In response to a step-change in input voltage (external speed setpoint), the ramp- function generator limits the rate of change of the speed setpoint fed to the speed controller to a technologically permissible value for the drive. Ramp-up and ramp-down times are adjustable via a potentiometer. The setting range of the potentiometer can, if necessary, be adapted to other conditions by changing a capacitor.

Speed controller

The speed controller has three inputs:

• The speed actual value can either be supplied from the integral armature voltage actual value sensing with
• (I x R) compensation or from a DC tacho-generator. The actual value voltage is adapted and the maximum speed set using two potentiometers for coarse and fine adjustment.
• The speed setpoint is either supplied from the integral ramp-function generator or directly via a terminal.
• A supplementary speed setpoint can be fed to the speed controller either directly via a terminal or via an adjustment potentiometer (e.g. compensator roll controller) or from the internal current actual value and potentiometer V (for (I x R) compensation for EMF control without tacho-generator).

The speed controller has separate amplifiers for the P and I components. The P gain and I component can be adjusted separately, and thus very easily at start-up.

A supplementary setpoint, preset via a terminal, can be added to the speed controller output value (current setpoint) via a summing amplifier connected after the speed controller.

The output value (current setpoint + supplementary current setpoint) is limited by a limiting controller (current limiting). Current limiting is internally set to a maximum value (the maximum being the converter's rated DC) and can be externally set to lower values via a terminal.

Current controller

The current controller is configured as a PI controller with gain and integral-action time designed for armature supply. The feedback can be adapted by soldering-in other components.

The current controller's output voltage is limited by two limiting controllers to values corresponding to the maximum and minimum converter firing-angle setting.

The current actual value is sensed with a current transformer and is fed to the current controller with electrical isolation. The current setpoint is supplied from the speed controller.

Trigger unit

The trigger unit generates the control pulses for triggering the thyristors, according to the output voltage of the current controller. The trigger unit automatically adapts itself to different supply frequencies or supply frequencies which change over the range 45 to 65 Hz during operation.

Automatic switch-on circuit and controller enable for units in the B2HK connection

When the converter has been switched on, the automatic switch-on circuit only enables operation when the power supply has established its voltages and the controllers are enabled.

Controller enable can be initiated immediately with the enable signal by the automatic switch-on circuit (terminals 8/20 jumpered) or in accordance with other operating states (terminals 8 and 20 connected via an enable contact).

Converters in B6C connection have a switch-on control as described for units in (B2)A(B2)C or (B6)A(B6)C.

Limit monitor

The limit monitor serves to detect whether a value has dropped below or exceeded a speed or current setpoint. In the basic configuration, a speed dropping below about 5 % of the rated speed is signaled (0 V at terminal 14).
The response value can be adapted by changing a resistor or by setting a potentiometer (for units in B6C connection).

Operating state display

The following operating states are indicated by LEDs:

• Converter is switched on.
• Controllers are enabled.
• Limit monitor has responded.
  

Functions of open-loop and closed-loop control for converters in (B2)A(B2)C or (B6)A(B6)C connections

Ramp-function generator

The ramp-function generator responds to a step-change in input voltage (external speed setpoint) by limiting the rate of change of the speed setpoint fed to the speed controller to a technologically permissible value for the drive. Ramp-up and ramp-down times are adjustable via two potentiometers independently of each other, over the range 2 to 30 s. The setting range can be adapted to other conditions, if necessary, by changing a capacitor.

Speed controller

The speed controller has three inputs:

• The speed actual value is supplied from a DC tacho-generator. The actual value voltage is adapted and the maximum speed set by means of two potentiometers for coarse and fine adjustment.
• The speed setpoint is supplied either from the integral ramp-function generator or through a free input and the matrix board.
• A supplementary speed setpoint can be fed in via a free input and the matrix board.
• The speed controller is configured with separate amplifiers for the P and I components. The P gain and I component can be adjusted separately, and thus very easily at start-up.

A supplementary current setpoint, preset via a free input and the matrix board, can be added to the output value of the speed controller (current setpoint) via a summing amplifier connected after the speed controller. The output value (current setpoint + supplementary current setpoint) is limited in the positive and negative directions by two limiting controllers (current limiting). The current limiting is internally set to a maximum value (the maximum being the rated DC). Lower values can be set externally by providing a suitable circuit on the matrix board, and by feeding in via a free (low-resistance) output terminal.

Current controller

The current controller has very high-grade dynamic performance with the following functions:

• Trigger unit feed-forward control with
• PI control with corrective intervention
• Current-dependent stability limit changeover.

The controller can be optimized without measuring instruments, using only the integral LEDs.

The PI controller feedback is designed for armature supply. It can be adapted to other applications by soldering-in other components.

The output voltage of the current controller is limited by two limiting controllers to values corresponding to the maximum and minimum firing-angle setting of the converter.

The current actual value is sensed via an AC current transformer (with series-connected rectifier and load resistor) and fed to the current controller. The current setpoint is supplied by the speed controller.

The trigger unit and autoreverse stage

The trigger unit generates the control pulses for triggering the thyristors, according to the output voltage of the current controller. By means of the auto-reverse stage, the trigger pulses are fed, according to the required torque direction, to the thyristors associated with the required current direction via pulse amplifiers and the transformer section. The trigger unit automatically adapts itself to different supply frequencies, or supply frequencies which change over the range 45 to 65 Hz during operation.

The auto-reverse stage, together with the current controller and trigger unit, reverses the current direction when the current setpoint polarity changes (torque direction), by logically processing the conditions.

Automatic switch-on and switch-off circuit

The automatic switch-on and switch-off circuit assumes the function of an external interlock comprising an IC system, relays or contactors.

After the switch-on command and after the power supply voltages have developed, the power contactor is switched-in through a relay integrated in the converter, and operation is enabled after a checkback signal and an optional, additional external controller enable signal.

After the switch-off command, the current is first reduced by shifting the trigger pulses to the inverter stability limit and the power contactor is then switched off when the current is zero.

Limit monitor

The limit monitor can be used to detect whether a value has dropped below or exceeded a speed or current setpoint. Responding of the limit monitor is indicated by an LED. The response value can be set on a potentiometer. The output of the limit monitor can also optionally be set to setpoint/actual value monitoring by changing a plug-in jumper (refer to “Setpoint/actual value monitoring and fault signal“).

The basic configuration is such that a signal is output when a speed drops below about 5 % of the rated speed (P24 at terminal 14). If the speed is not reached, an L signal is output at terminal 14.

Setpoint/actual value monitoring and fault signal

In their basic configuration, the converters have a stall protection function which responds if a long-term speed setpoint/actual value deviation occurs. The protective function can only be practically used in conjunction with the ramp-function generator. However, the protective function can be changed over to a setpoint/actual value signal by removing a -diode.

The output signal of the limit monitor can also be set to setpoint/actual value monitoring and used for a protective function (controller inhibit) by changing over a plug-in jumper.

Any fault signal from the protective function is stored and indicated by an LED. It can only be acknowledged and cleared by pressing a button.

Freely usable functions and mounting locations

Required supplementary functions can be created in the converter, to a limited extent, by using these facilities.

Four inputs and four outputs, each routed via terminals, as well as two inputs with switching function, are available. The inputs are equipped with resistors and capacitors for use as analog inputs. The outputs are routed via an RC circuit for noise suppression. The inputs with switching function each transfer an external electronic or contact switching signal in a floating arrangement through an optocoupler.

All signals are fed to a matrix board on which the required supplementary functions can be established. Various values from the power supply and closed-loop control are also fed to the matrix board.

Технические данные

Чертеж

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