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NORD Drivesystems BU0230 User Manual

Page 30

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Functional safety with NORD SK 200E frequency inverters

30

BU 0230 GB-2712

Size 4:

Input

circuitry

I

/

O

Control

Driver

µ

C

T

5

T

6

T

3

T

4

T

1

T

2

U

V

W

M

L

1

L

2

L

3

Logic

=

=

=

=

G

N

D

2

4

V

=

=

Control voltage

Internal voltage (Primary power)

3x High

1x Low

GND_SH

24V_SH

Frequency Inverter

Emergency

Option "safe pulse block"

stop

The semiconductor switches of the inverter (T1 to T6) are controlled by a highly complex pulse pattern. This
pulse pattern is generated by the microcontroller (µC) and amplified by the driver. The drivers convert the logic
signals on the control voltages of the semiconductor switch. The semiconductor switches are switched via the
control voltage and the pulse pattern is amplified and applied to the motor terminals. Due to the low-pass effect
of the motor, a three-phase pulse width modulated sine wave voltage - a three-phase system, results from the
pulsed voltage. The motor generates a torque.