Yacht Devices NMEA 2000 YDBM-01, Руководство пользователя

Страница: 18 / 66

— 18 —
V. Choosing a Shunt
A shunt is a precision resistor, with a low resistance value, used for current measurement. Shunts
in the range from 5A to 1200A are widely available. Another important parameter of the shunt, besides
current, is the voltage drop at maximum load. Typical voltage drop value is 75 mV, but 50 mV and 100 mV
shunts are also available.
Figure 1. A typical shunt appearance
The Battery Monitor measures voltage drop across a shunt in the range of -50..50 mV. This means that,
with the use of a shunt of a greater voltage drop than 50mV, the maximum measured current value
will be less than the shunt’s rated current. For 75 mV and 100mV shunts, the decrease will be,
respectively, 65% and 50%. For instance, with a 75 mV / 10 A shunt, the maximum measured current
will be approximately 6.5 A. In case of a 100 mV / 100 A shunt, the maximum measured current
will be approximately 50 A. Please take this into account when choosing a shunt.