Chapter 10 Technical Data; What This Chapter Contains; Derated Application - Hitachi S1 Series Basic Manual

S1 series standard inverter

Chapter 10 Technical data

10.1 What this chapter contains

This chapter describes the technical data of the inverter and its compliance to CE and other quality
certification systems.

10.2 Derated application

10.2.1 Capacity
Choose an inverter based on the rated current and power of the motor. To endure the rated power of
the motor, the rated output current of the inverter must be larger or equal to the rated current of the
motor. The rated power of the inverter must be higher or equal to that of the motor.
Note:
1. The maximum allowable shaft power of the motor is limited to 1.5 times the rated power of the
motor. If the limit is exceeded, the inverter automatically restricts the torque and current of the
motor. This function effectively protects the input shaft against overload.
2. The rated capacity is the capacity at the ambient temperature of 40° C.
3. You need to check and ensure that the power flowing through the common DC connection in the
common DC system does not exceed the rated power of the motor.
10.2.2 Derating
If the ambient temperature on the site where the inverter is installed exceeds 40° C, the altitude
exceeds 1000 m, or the switching frequency is changed from 4 kHz to 8, 12, or 15 kHz, the inverter
needs to be derated.
10.2.2.1 Derating due to temperature
When the temperature ranges from +40° C to +50° C, the rated output current is derated by 1% for
each increased 1° C. For the actual derating, see the following figure.
Note: It is not recommended to use the inverter at a temperature higher than 50° C. If you do, you
shall be held accountable for the consequences caused.
10.2.2.2 Derating due to altitude
When the altitude of the site where the inverter is installed is lower than 1000 m, the inverter can run
at the rated power. If the altitude is higher than 1000 m, the allowable output power is derated. For
details about the derating, see the following figure.
Derating coefficient (%)
100
90
80
60
40
20
-10 0 10 20
-200-
Temperature (℃)
30 40 50