Specifications

E - 8 Protections Ver: 0002
2.3 PERMANENT DUTY CYCLES ALLOWED FOR THE MOTOR,
CALCULATING THE I2T PRODUCT.
The drive software offers a procedure to calculate the integral of I
2
t applied to both the
synchronous and asynchronous motors.
The permanent watch of the I
2
t product tolerates any equivalent duty cycle producing a
maximum temperature equal to the one produced in the S1 cycle with a time constant set by
parameter MP13 -F01209- MotorThermalTimeConstant
However, the overheating caused by very high peak currents cannot be modelled with the I
2
t
calculation. In this case, the temperature sensors of the motors will be the ones detecting the
overheating.
Synchronous Motors
The table of chapter SM indicates the rated currents and the maximum peak currents at the
motors.
Asynchronous Motors
The table of chapter AM describes the maximum currents through the motor in the S1 and S6
duty cycles. When increasing the ambient temperature and the altitude, the operator must
decrease the demand on the requested cycles.
Nominal in S1
RF
Θmax
Θ
max
S1 cycle
S6 cycle -40%
R/F=4/6
DUTY CYCLES
according to the
IEC 34-1 standard
Losses
Temperature
Load
R: Rated in S6-40%
F: Free (no load)
Temperature
Load
in thermal balance
10 min