HEIDENHAIN TNC 410 M Technical Manual page 209

January 2008
The length of the ribbon cable is: l = 0.5 m
The length must be doubled because the cable is led to the inverter and then
back.
R = (rho x l) / A = (0.0179 (ohm x mm
U = R x I = 0.013 ohms x 9.4 A = 0.122 V = 122 mV
This results in a line drop > 100 mV. The ribbon cable alone does not suffice
for the +5-V supply. In addition, the litz wires must be used for supplying the
power of +5 V.
Example 3 of using a ribbon cable with a length > 0.6 m:
If ribbon cables with a length greater than 600 mm are used, the cable is led
doubled and the available cross section doubles as a result.
The length of the ribbon cable is: l = 0.7 m
R = (rho x l) / A = (0.0179 (ohm x mm
U = R x I = 0.009 ohms x 9.4 A = 0.085 V = 85 mV
The ribbon cable would suffice in this case.
+5 V Power Supply and Bus Cable
2
) / m x 2 x 0.5m) / 1.4 mm
2
) / m x 2 x 0.7m) / 2.8 mm
2
= 0.013 ohms
2
= 0.009 ohms
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