Sensor (Closed Loop) Vector Control (Requires Feedback Module), Sensorless (Open Loop) Vector Control, Speed Control (V / Hz), Torque Control (Constant), Torque Control (Variable)
Analog Input(s)
3 Inputs (0 - 10 VDC / -10 - 10 VDC / 4 - 20 mA)
Analog Output(s)
1 Output (0 - 10 VDC), 1 Output (4 - 20 mA)
Control Input(s)
1 Input (Motor Thermister), 8 Inputs (NPN)
Control Output(s)
1 Output (Relay), 5 Outputs (NPN)
Integrated EPM Module:
No
Integrated Keypad:
Yes
Integrated Fwd / Rev Switch:
No
Integrated Speed Pot:
No
Integrated Disconnect:
No
Integrated Brake Chopper:
No
Integrated Communications:
Modbus RTU (RS-485)
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Description
Estimated reading time: 11 minutes
Introduction to Hitachi SJ700B Variable Frequency Drives VFDs
The Hitachi SJ700B Variable Frequency Drives VFDs are a robust series of inverters designed for superior performance in demanding industrial applications. At their core, these drives precisely control the speed and torque of three-phase AC motors by converting fixed-frequency AC input power into a variable-frequency, variable-voltage AC output. This capability not only optimizes machine performance but also offers significant energy savings. According to Hitachi Drives, the series is recognized as one of the most powerful in its class, delivering high torque and precision.
Building on its predecessor, the SJ700, the SJ700B series incorporates advanced features that enhance its versatility. One of the key technologies is its improved sensorless vector control (SLV), which provides high starting torque and stable operation even at low speeds. As a result, these drives are exceptionally well-suited for a wide range of applications, including pumps, fans, compressors, extruders, and material handling conveyors. Moreover, Hitachi SJ700B AC Drive notes its ability to reassert Hitachi's leadership in high-performance AC drives, capable of holding a motor shaft in a servo lock status.
The Hitachi SJ700B inverter is also engineered for user-friendliness and simplified integration. For instance, the drive includes a built-in PLC-like functionality called EzSQ (“Easy Sequence”), allowing users to create custom logic programs without needing a separate controller, a feature highlighted by Hitachi. Furthermore, powerful auto-tuning functions help optimize motor performance quickly and efficiently. The drive also features a removable keypad with a multi-line display for straightforward setup and monitoring, cementing its role as a flexible and powerful solution for modern motor control systems.
Safety First: Essential Precautions for SJ700B VFD Manual Handling
Properly handling Hitachi SJ700B Variable Frequency Drives VFDs is paramount to ensuring personnel safety. These sophisticated devices operate at lethal voltages and contain complex power electronics, as detailed by sources like Asb-Distribution. Consequently, all technicians must treat the equipment with extreme caution, adhering to established safety standards like NFPA 70E and OSHA regulations. Before touching any component, it is crucial to consult the specific variable speed drive manual for warnings and detailed procedures.
The most critical safety measure is implementing a comprehensive Lockout/Tagout (LOTO) procedure before performing service. First, completely disconnect all incoming AC power sources from the Hitachi SJ700B inverter, then apply a personal lock and tag. It is not enough to simply turn off the power; you must verify a zero-energy state. For instance, always use a properly rated multimeter to test for the absence of voltage at the input terminals and DC bus, as the drive's internal components are quite powerful, as noted by Hitachi Drives.
In addition to LOTO, wearing the appropriate Personal Protective Equipment (PPE) is non-negotiable. Arc-rated clothing and voltage-rated gloves are essential to protect against electrical hazards. After de-energizing, remember that internal DC bus capacitors store a hazardous charge, a key aspect of these advanced systems mentioned by Hitachiacdrive. Therefore, always wait for the manufacturer-specified discharge time—typically found in the SJ700B VFD manual—before your hands make any contact with the internal components.
Initial Setup and Wiring for Hitachi SJ700B Inverters
The Hitachi SJ700B series offers exceptional performance and reliability for demanding industrial applications, setting a high standard for variable frequency drives.
Proper initial setup and wiring are fundamental for the safe and reliable operation of Hitachi SJ700B inverters. Before starting, it is crucial to consult the specific variable speed drive manual for your model to verify all electrical specifications. First, ensure the incoming supply voltage matches the VFD's rating as indicated on the nameplate, which is available in both 200-240 VAC and 380-480 VAC classes according to distributors like Asb-Distribution. Similarly, you must confirm that the drive’s current and power ratings are appropriately sized for the connected AC motor load, adhering to all National Electrical Code (NEC) guidelines. This initial verification step prevents catastrophic failures and ensures system compatibility from the outset.
Wiring Hitachi SJ700B VFD Connections
Next, you can proceed with the physical wiring connections. Always begin by connecting a suitable equipment ground to the designated ground terminal, which is a critical safety measure. Subsequently, connect the three-phase AC input power to the R/L1, S/L2, and T/L3 terminals, ensuring all connections are torqued to the specifications listed in the Hitachi SJ700B Instruction Manual manual. The three-phase motor leads are then connected to the U/T1, V/T2, and W/T3 output terminals. It is essential to use the correct wire gauge for both power and motor connections based on the full load amperage (FLA) to prevent overheating. For instance, control wiring for start/stop commands or speed references should be routed separately from high-voltage power cables to minimize electrical noise interference.
Finally, a thorough inspection is necessary before applying power to any hitachi sj700b variable frequency drives vfds. Double-check all wiring terminations for tightness and correctness, and confirm that the installation provides adequate ventilation clearance around the unit for proper heat dissipation. Many models in this series include built-in EMC filters to reduce electromagnetic interference, a feature highlighted by Hitachi, but proper grounding remains essential for their effectiveness. Following these detailed steps, as outlined in technical documents like the SJ700B brochure, ensures the drive is configured correctly from the start, paving the way for successful commissioning and long-term performance.
Step-by-step Hitachi VFD Setup and Programming
Proper Hitachi VFD setup is crucial for optimizing the performance and longevity of Hitachi SJ700B Variable Frequency Drives VFDs. After completing the initial wiring, configuration begins using either the standard removable keypad or the PC-based ProDriveNext software, which according to Hitachi Press Release Archive, is provided at no charge. For instance, the first step involves entering fundamental motor nameplate data into the drive’s parameter settings. This includes the motor’s voltage, full-load amperage (FLA), horsepower or kW rating, and rated speed in RPM. Consulting the SJ700B VFD manual is essential during this process to ensure every parameter is correctly identified and accurately entered, thereby establishing a correct baseline for the drive's control algorithms.
Hitachi SJ700B Auto-tune for Motor Control
Once the basic motor data is programmed, the next critical step is performing an auto-tune. This function allows the Hitachi SJ700B inverter to measure key motor characteristics like stator resistance and rotor inductance while the motor is stationary. Consequently, as noted by Hitachi Drives, the drive adapts its control algorithm for the specific connected AC motor, which is vital for achieving precise speed regulation and maximizing torque in sensorless vector control mode. Skipping this step can result in suboptimal performance, including poor speed holding under varying loads and potential motor overheating. For this reason, it is a mandatory procedure for any high-performance application.
With the motor tuned, you can then configure application-specific parameters. This includes setting acceleration and deceleration times, establishing minimum and maximum speed limits, and defining the V/f pattern or selecting vector control mode. Furthermore, the SJ700B features an integrated "Easy Sequence" (EzSQ) programming function, which essentially embeds a small PLC within the drive. As explained by Precision-Elec, this powerful tool allows for creating simple logic sequences without external controllers. In addition, operators can set up control sources, choosing between the digital keypad, terminal strip inputs for start/stop and speed reference signals, or network communications like Modbus RTU, which is detailed by Hitachiacdrive.
Decoding Common Hitachi SJ700B VFD Fault Codes
When an issue arises with Hitachi SJ700B variable frequency drives VFDs, the built-in diagnostics are the first line of defense for any technician. The drive’s keypad immediately displays a fault code, providing a crucial starting point for troubleshooting to minimize equipment downtime. According to Hitachi SJ700B AC Drive, the clear feedback from the operator interface is essential for monitoring and diagnostics. Understanding these codes is fundamental to performing swift and accurate repairs, ultimately ensuring the continued reliability of the AC motor system.
Following proper safety protocols, including wearing personal protective equipment (PPE), is critical when manually handling heavy Hitachi SJ700B VFDs to prevent injury and ensure correct installation.
Overcurrent Faults (e01, E02, E03) in Hitachi Industrial Drives
Overcurrent faults (E01 during acceleration, E02 during deceleration, E03 at constant speed) are among the most frequent alerts. These codes signify that the current to the motor has surpassed the drive’s protective threshold, which can happen for several reasons. For instance, a sudden mechanical jam, a short circuit in the motor or its wiring, or excessively aggressive acceleration settings can all trigger this fault. The initial troubleshooting step involves a thorough inspection of the motor for mechanical binding and checking all power wiring for damage. Subsequently, it is wise to confirm that the drive’s control algorithms are correctly matched to the motor, as proper auto-tuning results are key for performance, a point emphasized by sources like Hitachi Drives.
Resolving SJ700B VFD Over/undervoltage Faults
Overvoltage and Undervoltage Alarms (e07, E09)
Voltage-related faults require attention to the power circuit. An Overvoltage fault (E07), for example, typically occurs when a load drives the motor during rapid deceleration, causing the motor to act as a generator and send voltage back to the VFD. This regenerative condition, as detailed by Precision Electric, can often be resolved by extending the deceleration time or by installing a dynamic braking resistor to dissipate the excess energy. On the other hand, an Undervoltage fault (E09) indicates the incoming AC supply has dipped below the drive’s minimum operational limit. Consequently, technicians should verify the stability of the main power source and inspect all fuses, breakers, and terminal connections for potential issues.
Heat and External Trip Fault Codes (e15, E05)
Finally, environmental and external signals can also cause a trip. A Heatsink Overheat fault (E15) signals that the IGBTs or other internal components are exceeding their thermal limits, a critical warning to prevent permanent damage. Common causes include a malfunctioning cooling fan, obstructed vents, or high ambient temperatures around the unit. In contrast, an External Trip (E05) is initiated by an external safety or control device wired to one of the drive's intelligent input terminals. Troubleshooting this fault requires tracing the specific control circuit, which, as noted by Hitachi SJ700 Brochure, is highly configurable. Before any hands-on work, always consult the specific SJ700B VFD manual and adhere strictly to Lockout/Tagout (LOTO) safety procedures.
Advanced Troubleshooting for Hitachi Industrial Drives
When standard fault codes on a Hitachi SJ700B inverter do not resolve an issue, it becomes necessary to employ advanced troubleshooting methods. Consequently, these deeper diagnostics shift focus from the keypad display to a comprehensive analysis of the entire drive system, including the AC motor and its load. This process often involves verifying that motor nameplate data is correctly entered and performing an auto-tune, which allows the VFD's control algorithm to match the specific motor characteristics. According to Hitachi Drives Programming, proper tuning is a critical step for achieving optimal torque and speed control.
If performance problems persist, the next step involves safely inspecting the drive's internal power components after executing proper Lockout/Tagout (LOTO) procedures. For instance, technicians can measure the DC bus voltage under various load conditions to identify issues with the input power or the drive's rectifier circuit. Furthermore, intermittent tripping or erratic motor behavior might point to a failing Insulated-Gate Bipolar Transistor (IGBT), which requires specialized equipment to test accurately. The SJ700B includes protective functions, but as noted by Hitachi SJ700V Inverter, external factors can still lead to component stress over time.
Properly wiring the control and power terminals is a critical first step. Following the SJ700B VFD manual ensures a safe and reliable installation for your industrial drive.
Beyond the hardware, complex operational issues can originate from the drive’s internal programming and network communications. The integrated EzSQ (“Easy Sequence”) programming function, for example, acts as a small PLC, but flawed logic can introduce faults that are difficult to trace. Hitachi Press Archive highlights this powerful built-in capability for creating customized operational sequences. In other words, troubleshooting may require debugging the EzSQ program itself, not just standard VFD parameters. Verifying network settings is also essential, particularly when using optional fieldbus cards for protocols like EtherNet/IP, a feature mentioned by Precision Electric.
Preventive Maintenance for Hitachi SJ700B Variable Frequency Drives VFDs
Proactive preventive maintenance is essential for maximizing the operational life and reliability of Hitachi SJ700B variable frequency drives VFDs. Before performing any work, always follow strict Lockout/Tagout (LOTO) procedures to ensure the system is de-energized. A thorough routine includes visually inspecting the unit for dust or debris that can impede airflow and cause overheating, a primary threat to power components like IGBTs. Furthermore, it is critical to periodically check and tighten all power and control wiring connections. As noted by Hitachi SJ700 Brochure, while the drive's construction is robust, these simple physical checks prevent high-resistance connections and potential faults.
Beyond physical checks, monitoring the VFD's environment and performance data is crucial. For instance, verify that cooling fans are functioning correctly and that the ambient temperature remains within the specified range found in the variable speed drive manual. Periodically recording key electrical measurements like input voltage and output current establishes a valuable operational baseline for troubleshooting. According to Precision Electric, utilizing such diagnostics is a key benefit of modern VFDs.
Finally, a critical but often overlooked maintenance task is the regular backup of drive parameters. Configuration settings can be lost during a component failure, which complicates recovery. Using PC-based software like ProDriveNext, as mentioned by Hitachi SJ700B-150LFUF AC Drive, ensures that you can quickly commission a replacement drive. This simple step significantly reduces downtime and is indispensable for managing any Hitachi drive replacement scenario.
Conclusion: Maximizing Uptime with Your SJ700B VFD
In conclusion, the Hitachi SJ700B inverter stands out as a powerful and reliable solution for a vast range of motor control applications. Throughout this guide, we have explored everything from initial safety precautions and wiring to advanced programming and troubleshooting of fault codes. Ultimately, the robust design and sophisticated features of these Hitachi industrial drives provide the tools necessary for precise control and enhanced system performance. By leveraging features like sensorless vector control and the integrated EzSQ programming, operators can significantly improve process efficiency and reliability.
Mastering the Hitachi SJ700B variable frequency drives VFDs involves more than just understanding their technical specifications; it requires a commitment to proper procedure. For instance, adhering to the detailed guidelines in the variable speed drive manual for setup, preventive maintenance, and fault diagnosis is paramount for extending the unit’s service life. As highlighted by industry experts, consistent maintenance directly translates to reliability and uptime gains, which are critical in any industrial setting. Consequently, a well-maintained SJ700B is not just a component but a cornerstone of operational stability, as noted by sources like Hitachi Drives.
By following the best practices outlined for safety, setup, and maintenance, you can ensure your Hitachi SJ700B operates at peak performance for years to come. This proactive approach not only prevents costly downtime but also maximizes the return on your investment in these advanced drives. Therefore, whether you are commissioning a new system or maintaining an existing one, a thorough understanding of the drive's capabilities and requirements is essential. For any technician facing motor control challenges, the SJ700B offers a dependable and feature-rich solution, backed by Hitachi engineering excellence.
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