Hitachi America, Ltd.’s Industrial Systems Division announced the introduction of the high-capacity SJ700 series of inverters. The SJ700 extends Hitachi’s model range up to 500 hp, and significantly expands on the performance, capabilities and functions of the SJ300. Three models, 250 hp, 400 hp and 500 hp are being released at this time. The SJ300 remains to cover the range from 200 hp and below.
Hitachi is offering what it describes as an improved Sensorless Vector (SLV) control algorithm that enables the SJ700 to develop more than 150% starting torque at 0.3 Hz. Using Hitachi’s "0 Hz Domain" open-loop control mode, the SJ700 can develop 130% torque at 0Hz, suitable for vertical lift applications. At the same time, Hitachi states that it has greatly simplified the autotuning process, making commissioning trouble-free.
Another noteworthy enhancement in the SJ700 is Hitachi’s Easy Sequence (EzSQ) built in programming function. It’s like having a Industrial Control System (PLC) built into the inverter. In many cases, the need for a separate PLC can be eliminated. The program is developed on a PC, and then downloaded to the inverter using the simple-to-use EzSQ software provided at no charge.
Hitachi states that it has packed other new features into the SJ700, such as patented Micro Surge Voltage suppression (to protect the motor winding insulation), advance trip avoidance functions, configurable sink/source logic on I/O, and much more.
The SJ700 also has a built-in RS485 Modbus/RTU communication, and options for other communications networks, such as Ethernet Modbus/TCP, DeviceNet, Profibus and LonWorks. The SJ700 can be configured via the front-mounted keypad or using Hitachi’s ProDrive PC-based software.
