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D-80
Additional information
Thermal characteristics of
switchboards
Two cubicles with busbar compartment, 800 mm
wide, 1000 mm deep, two 300 mm wide ducts, IP30
Diversity factor: 0.7
Ambient temperature around the switchboard: 35 °C
Cubicle
1
: P(W) of device zone = 580 W
Cubicle
2
: P(W) of device zone = 180 W
NSX250
NSX NSX NSX NSX
NSX400
Linergy FC distribution block
Linergy FM 200 A
DD385566.eps
Application of the diversity factor
In the configuration below, the standardised diversity factor (K div.) for a total of 14
outgoing circuits is 0.6, i.e. 60 % of In for each outgoing circuit.
Schneider Electric prefers a more conservative approach and therefore divides the
installation into four main circuits:
bb
Compact NSX250
bb
200 A Linergy FM: 8 outgoers
V
K div. = 0.7
bb
Linergy FC: 4 outgoers
V
K div. = 0.8
bb
Compact NSX400.
1 Compact NSX250 + 1 Linergy FM 200 A + 1 Linergy FC + 1 Compact NSX400
V
4 outgoers, i.e. a diversity factor of 0.8.
As a result, the current flowing in each circuit is at least 70 % and up to 80 % of In.
Calculation of the power dissipated by
devices in the incoming cubicle
Dissipated power of the NT1600 indicated by the manufacturer: 460 W. The power
dissipated by the connections is approximately 30 % of the device P(W):
0.3 x 460 = 138 W.
Power of circuit breaker + connections = 460 + 138 = 598 W at 1600 A.
For I² (the Watts are proportional to the square of the current) at 1410 A
(In of the incoming device):
Dissipated power of the Compact NSX250 indicated by the manufacturer: 42 W.
Dissipated power of the connections: 0.3 x 42 = 12.6 W.
Power of circuit breaker + connections = 42 +12.6 = 54.6 W at 250 A.
For 200 A (the tested value):
54.6 200
2
= 35 W x
250
2
Dissipated power of the Linergy FC and its four Compact NSX250 circuit breakers:
4 x 35 W (same calculation as above) = 140 W
Sum of the dissipated power in the incoming cubicle:
P(W) = 405 + 35 +140 =
580 W
Thermal management of
switchboards
Example