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Sizing fuse, circuit breakers for NX servo systems

Posted: Wed Mar 04, 2015 3:43 pm
by om_tech_support_JT
Q: I'm trying to size a circuit breaker for my NX series servo motor and driver system. What is the maximum current that my product will require?

A: When sizing a fuse or a circuit breaker, you need to account for inrush current as well as the maximum current that the product will use. In the NX series catalog, we only show the rated current of our products. Rated current is the current that is required while operating in the continuous duty region of the motor's speed torque curve. The maximum current is required when operating in the limited duty region. Maximum current is approximately 3 times the rated current.

For more information, please look at PAGE B-16 of the NX series catalog linked below and reference the *3 note as well as the speed torque curves. For an NX640AS-3 system, the rated input current is 2.8 amps. If we multiply this number by 3, the maximum current becomes 8.4 amps. You should size the circuit breaker for this value. However, additional testing may be necessary since required current depends on factors such as load and speed. ... series.pdf