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11. CHARACTERISTICS
11. CHARACTERISTICS
11.1 Overload Protection Characteristics
An electronic thermal relay is built in the servo amplifier to protect the servo motor and servo amplifier
from overloads. The operation characteristics of the electronic thermal relay are shown below. Overload 1
alarm (A. 50) occurs if overload operation performed is above the electronic thermal relay protection curve
shown below. Overload 2 alarm (A. 51) occurs if the maximum current flew continuously for several
seconds due to machine collision, etc. Use the equipment on the left-hand side area of the continuous or
broken line in the graph.
If load is applied at stop (during servo lock), 70% of the rated torque must not be exceeded.
HC-AQ Series
1000
100
10
1
0.1
0
50
150
200
250
300
Load ratio [%]
100
During stop
During rotation
Ope
rat
ion t
im
e
[
s
]
Fig 11.1 Electronic Thermal Relay Protection Characteristics
