3. System Design
MV3DB Series DB Units
ALSPA MV3000e Dynamic Braking Units
(07/06)
Page 3-6
Table 3-1 Optional braking resistors and associated maximum cable sizes
Cable Size (Maximum)
DB Unit
Optional Braking Resistor
Metric
Sizes
mm
2
AWG Sizes
MV3DB045S5 MV3DBR045S4
6
10
MV3DB045S5 MV3DBR038S5
6
10
MV3DB092S5 MV3DBR092S4
16
6
MV3DB092S5 MV3DBR076S5
16
6
MV3DB061S6 MV3DBR061S6
16
6
MV3DB247S5 MV3DBR247S4
50
1/0
MV3DB247S5 MV3DBR231S5
50
1/0
MV3DB185S6 MV3DBR185S6
50
1/0
MV3DB391S5 MV3DBR391S4
120
4/0
MV3DB391S5 MV3DBR308S5
120
4/0
MV3DB246S6 MV3DBR246S6
120
4/0
Outside the cabinet the braking resistor cables must be segregated from other cables by at
least 300 mm (12 in).
To avoid EMC problems the resistor cables outside the cabinet should be screened (e.g.
NYCWY according to VDE 0276-603 or steel wire armoured) or fully enclosed in metallic
trunking. The screen or metallic trunking must be continuous throughout its length and be
connected directly to, or glanded to, both the cabinet and the resistor casing.
3.8 Resistor
Protection
3.8.1 Internal
Protection
The drive monitors the power being dissipated by the braking resistor to avoid the resistor
overheating. Figure 3-2 shows a typical stop/start cycle. If a braking resistor other than a
standard
Converteam
resistor is used, it should be chosen to comply with the requirements of
Sections 2 or 3.4.
The following aspects of the braking resistor’s power capability are entered in the drive’s
parameters:
•
Average power capability over total stop/start cycle (P23.01)
•
Peak power capability (P23.02)
•
Time at peak power (P23.03)
The drive uses these parameters to model the resistor temperature. See Section 5.3 for further
information.
