Ch.585
—————— Wiring procedure ——————
The use of different braking resistors from those indicated on table 5.8.2.1, requires to take into considera-
tion the meaning of following formulas:
BU ovld time [s] = E
BR
/
P
PBR
(time of braking at limit condition for cycle with triangular profile)
BU duty cycle % = (P
NBR
/ P
PBR
) x 100
Table 5.8.2.2: Braking thresholds for different Mains
Mains Braking threshold
voltage V
BR
[V]
230Vac 400
400Vac680
460Vac /480 Vac 780
avy4200
The result of these calculations must be assigned to the corresponding parameters in menu FUNCTIONS\Brake
unit. When the duty cycle exceeds the data entered, the alarm BU overload automatically occurs in order to
prevent possible damages to the resistor.
The following table can be used to choose an external resistor, different from the standard series.
Table 5.8.2.3: Technical data of the internal braking units
Inverter Minimum
type I
RMS
I
PK
TR
BR
[A][A][s][ohm]
1007
1015
1022
1030
2040
2055
2075
3110
12
22
17
36
3150 17 31
16
26
4185
4220
4300
37 23
4370
29 37
5450
5550
6750
7900
71100
71320
81600
82000
avy4210
67
4.1
6.6
7.8
12
19
16
100
External braking unit (optional)
1078
50 104 22 7.5
18 52 42 15
I
RMS
: Nominal current of the braking unit
I
PK
: Peak current deliverable for 60 seconds max.
T : Minimum cycle time for a working at I
PK
for 10 seconds
Generally the following condition must be satisfed
I
RMS
1P T
PBR BR
RT
BR C
2
Each drive is provided of the terminals 26 and 27 which allows control of one or more external braking units,
parallel connected. The drive will act as Master and the external braking units BU32 must be configured as
Slave.
In this way it will be possible to utilize the internal I
2
x t protection also using external BU (see “AVy-
Function description and parameters” instruction manual (available on CD), section 2.15.9 Braking unit).
In case of using more external BUs, each BU with a resistor (all the same) refers to the parameters calcula-
tion of a single unit.
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