
50
ADL500 • Quick installation guide - Specifications and connection
7.10 Braking
There are various possible types of braking:
- Internal Braking Unit
- Injection of direct current from the Inverter into the motor (D.C. braking)
There are two essential differences between the two braking methods:
- A braking unit can be used for speed reduction (e.g.: from 1000 to 800 rpm), whereas D.C. braking can only be
usedfor braking to standstill.
- The energy in the drive is converted into heat in both cases. This conversion takes place in a braking resistor
encased in the braking unit. With D.C. braking, the energy is converted into heat in the motor itself, resulting in a
further rise in motor temperature.
7.10.1 Braking unit (internal)
Frequency-regulated asynchronous motors during hyper-synchronous or regenerative functioning behave as genera-
tors, recovering energy that flows through the inverter bridge, in the intermediate circuit as continuous current.
This leads to an increase in the intermediate circuit voltage.
Braking units (BU) are therefore used in order to prevent the DC voltage rising to an impermissible value. When used,
these activate a braking resistor that is connected in parallel to the capacitors of the intermediate circuit. The feedback
energy is converted to heat via the braking resistor (R
br
), thus providing very short deceleration times and restricted
four-quadrant operation.
In the standard configuration, ADL drives (
≤
55kW) comprise an internal braking unit.
E
3
M
_
R
BR
BU
U
ZK
Figure 7.10.1: Operation with braking unit (circuit diagram)
Note!
When the internal braking unit is present the protection must consist of fast-acting fuses! Follow the relative assembly instructions.
A twisted cable must be used for the connection of the braking resistor (terminals BR and C or BR1 and BR2). If the
resistor includes a thermal protection device (Klixon), this must be connected to the "External fault" input of the drive.
Tabella 7.10.1: Technical data of the internal braking unit
Size
I
rmS
(A)
I
pk
(A)
R
br
(
Ω
)
ADL5...-...-4, 3ph
1040
8.3
11.8
68
1055
8.3
11.8
68
1075
11.5
16.3
49
2110
20.2
28.5
28
2150
20.2
28.5
28
I
rms
Braking unit rated current, duty cycle = 50%
I
pk
Peak current that can be delivered for max 60 seconds
R
br
Minimum braking resistance value
Tabella 7.10.2: Braking unit intervention threshold
Size
V
br
@ 480 V
V
br
@460 V
V
br
@ 400 V
V
br
@ 230V
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ADL5...-...-4, 3ph
1040 ... 2150
800 Vdc
790 Vdc
768 Vdc
758 Vdc
670 Vdc
660 Vdc
394 Vdc
384 Vdc
Note!
For the combination of recommended braking resistors refer to chapter
Содержание ADL500
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