Nidec Commander C200 Power Installation Manual page 63

Table 4-7 Minimum resistance values and peak power rating for the braking resistor at 40 °C (104 °F)
Model
200 V
05200250
06200330
06200440
400 V
05400270
05400300
06400350
06400420
06400470
575 V
05500030
05500040
05500069
06500100
06500150
06500190
06500230
06500290
06500350
* Resistor tolerance: ±10 %. The minimum resistance specified are for stand-alone drive systems
only. If the drive is to be used as part of a common DC bus system different values may be
required. Contact the supplier of the drive for more information.
For high-inertia loads or under continuous braking, the continuous power dissipated in the braking
resistor may be as high as the power rating of the drive. The total energy dissipated in the braking
resistor is dependent on the amount of energy to be extracted from the load.
The instantaneous power rating refers to the short-term maximum power dissipated during the on
intervals of the pulse width modulated braking control cycle. The braking resistor must be able to
withstand this dissipation for short intervals (milliseconds). Higher resistance values require
proportionately lower instantaneous power ratings.
In most applications, braking occurs only occasionally. This allows the continuous power rating of the
braking resistor to be much lower than the power rating of the drive. It is therefore essential that the
instantaneous power rating and energy rating of the braking resistor are sufficient for the most
extreme braking duty that is likely to be encountered.
Optimization of the braking resistor requires careful consideration of the braking duty.
Select a value of resistance for the braking resistor that is not less than the specified minimum
resistance. Larger resistance values may give a cost saving, as well as a safety benefit in the event
of a fault in the braking system. Braking capability will then be reduced, which could cause the drive
to trip during braking if the value chosen is too large.
The following external brake resistors are available from the supplier of the drive for sizes 5 and 6.
Unidrive M/HS Frame 5 to 6 Power Installation Guide
Issue Number: 8
Minimum resistance *
Ω
19
10
38
22
20
80
15
Instantaneous power
rating
kW
8.9
16.9
17.8
30.8
33.8
12.1
64.1
Continuous power
rating
kW
8.6
12.6
16.4
16.2
19.6
21.6
25
32.7
2.6
4.6
6.5
8.7
12.3
16.3
19.9
24.2
31.7
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