GEFRAN-SIEI ARTDrive Vector V2 Series - Page 66

66 • Chapter 4 Wiring Procedure ARTDrive V2 series - Instruction Manual
Figure 4.8.2.2: Braking Cycle with T
BR
/ T
C
= 20%
T
C
P, n
T
BR
n
t
The standard resistor can be used for couplings, different from the ones above.
The peak over load which is applied when the braking chopper is in steady state
is:
P =
PBR
V [V]
BR
2
R [ohm]
BR
=[w]
Where: V
BR
= braking unit threshold (see table 4.8.2.2)
With reference to the figure 4.8.2.3, where the power profile is the typical
triangular one, the following example can be taken into consideration (see also
table 4.8.2.1).
Resistor model: MRI/T600 100R
Rated power P
NBR
= 600 [W]
Maximum energy E
BR
= 22kJ
Inverter mains supply = 460V
From table 4.8.2.2: V
BR
=780V
T
BRL =
2
E
BR
P
PBR
=
24000
6084
=7.8[s]2
P
PBR =
V BR
R
BR
2
=
780
100
2
=6084[W]
CASE A) If T
BR
≤≤
≤≤
≤ E
BR
/ P
NBR
the following conditions must be met:
1) P
MB
≤≤
≤≤
≤ 2 . E
BR
/ T
BR
Where: P
MB
is the peak power of the cycle (see.fig. 4.8.2.3)
2)
PxT
2T
MBBR
C
£ P
NBR
The average power of the cycle must not be higher than the rated power of the
resistor.