Baldor MotiFlex e100, Installation Manual, Page: 57 / 220

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Basic Installation 3-41 MN1943
3.9.5 Resistor temperature derating
The RGJ... regeneration resistors shown in Table 6 can achieve their stated power rating only
when mounted on a heatsink. In free air a derating must be applied. Furthermore, in ambient
temperatures greater than 25 °C (77 °F), a temperature derating must be applied - see Figure 23.
The RGA... regeneration resistors shown in Table 6 must operate in ambient temperatures not
exceeding 80°C (176°F). The resistor should be mounted vertically, as shown in section A.1.4.
If mounted in any other position, its power rating must be derated by 35%.
40 80 120 160 200 240 280
Ambient temperature (°C)
%
of
rat
ed
pow
er
0
20
40
60
80
100
1
2
3
4
1
On heatsink: all models.
2
Free air: RGJ160, RGJ1150.
3
Free air: RGJ260, RGJ2150, RGJ3150, RGJ360, RGJ368.
4
Free air: RGJ515, RGJ533.
Typical heatsinks (metal plate):
RGJ160, RGJ1150:
200 mm x 200 mm x 3 mm
All other RGJ models: 400 mm x 400 mm x 3 mm
25
Figure 23 - Regeneration resistor temperature derating
The RGJ... regeneration resistors listed here do not provide a fail-safe safety
mechanism. For safety reasons and UL compliance, they will become
open-circuit in the event of failure. This will cause the MotiFlex
e
100 to trip due
to overvoltage, leaving the motor in an uncontrolled state. Further safety
mechanisms such as a motor brake will be required, especially for applications
involving suspended or tensioned loads.
WARNING