Technical Data
Instruction handbook b maXX BM4400, BM4600, BM4700
Document No.: 5.12008.07
107
of 358
3
Preconditions for the cooling versions F/W (through hole devices):
Provide adequate protection against contact. Install grids around the heat sink and the
resistors. Assure, that enough air can circulate and that no heat accumulation can devel-
op under the protective cover.
Preconditions for cooling version Z (mounting into the control cabinet):
Install the devices into the control cabinet, that no heat accumulation can develop above
the devices. Air circulation must be possible. In spite of air circulation elevated tempera-
tures can occur above the devices. Do not install cables or cable channels above the de-
vices. At the devices BM443X and BM444X do not install the connection cables directly
above the mounting plate of the device, where the hot air rises.
When dimensioning, consider that 10 % of brake resistor power is not dissipated via the
cooling water, but is an additional power loss, which heats the cabinet. Provide an ade-
quate fresh air supply.
Calculations Precondition for calculation:
The brake power of the internal brake resistors must decrease straight proportional from
the brake peak power to 0.
The brake power time area A must be converted in an equivalent triangular time area. The
resulting parameters P
S
and t
on
must be used for the further calculations.
Figure 50: Conversion brake power time area in triangular time area
At
1
P
S
1
2
---
t
2
P
S
+
1
2
---
t
on
P
S
==
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