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Brake chopper
13-3 Brake chopper
!Warning The table gives the minimum values of the brake resistors. Do not use
268
All VSD sizes can be fitted with an optional built-in brake chopper. The brake
resistor must be mounted outside the VSD. The choice of the resistor
depends on the application switch-on duration and duty-cycle. This option can
not be after mounted.
resistors lower than this value. The VSD can trip or even be damaged due to
high braking currents.
The following formula can be used to define the power of the connected brake
resistor:
(Brake level VDC)2
Presistor =
Rmin
Where:
P
required power of brake
resistor
resistor
Brake level V
DC brake voltage level (see Table 35)
DC
Rmin
minimum allowable brake resistor
(see Table 35 and Table 36)
ED%
effective braking period. Defined as:
Active brake time at
nominal braking
power [s]
ED% =
120 [s]
Table 34 Brake Voltage levels
Supply voltage (V
(set in menu [21B]
220–240
380–415
440–480
500–525
550–600
660–690
Table 35 Brake resistor SX 400V type
Type
SX-D40P7-EF
SX-D41P5-EF
SX-D42P2-EF
SX-D43P0-EF
SX-D44P0-EF
SX-D45P5-EF
SX-D47P5-EF
SX-D4011-EF
SX-D4015-EF
SX-D4018-EF
SX-D4022-EF
x ED%
Maximum value of
1= continuous braking
)
AC
Rmin [ohm] if supply 380–
415 V
AC
43
43
43
43
43
43
43
26
26
17
17
Section 13-3
Brake level (V
)
DC
380
660
780
860
1000
1150
Rmin [ohm] if supply 440–
480 V
AC
50
50
50
50
50
50
50
30
30
20
20
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