Hitachi SJ700 Application to Motors, Characteristic of the motor, Temperature increase, Mechanism

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FOR CORRECT OPERATION

Application to Motors

Application to general-purpose motors

 

The overspeed endurance of a general-purpose motor is 120% of the rated speed for 2 minutes (JIS C4,004). For operation at higher

Operating frequency

than 60Hz, it is required to examine the allowable torque of the motor, useful life of bearings, noise, vibration, etc. In this case,

 

be sure to consult the motor manufacturer as the maximum allowable rpm differs depending on the motor capacity, etc.

 

 

Torque characteristics

The torque characteristics of driving a general-purpose motor with an inverter differ from those of driving it using commercial power

(starting torque decreases in particular).Carefully check the load torque characteristic of a connected machine and the driving torque

 

characteristic of the motor.

 

 

Motor loss and

The torque characteristics of driving a general-purpose motor with an inverter differ from those of driving it using commercial power

temperature increase

 

 

 

Noise

When run by an inverter, a general-purpose motor generates noise slightly greater than with commercial power.

 

When run by an inverter at variable speeds, the motor may generate vibration, especially because of (a) unbalance of the rotor

 

including a connected machine, or (b) resonance caused by the natural vibration frequency of a mechanical system. Particularly, be

Vibration

careful of (b) when operating at variable speeds a machine previously fitted with a constant speed motor. Vibration can be minimized

 

by (1) avoiding resonance points using the frequency jump function of the inverter, (2) using a tire-shaped coupling, or (3) placing a

 

rubber shock absorber beneath the motor base.

 

 

Power transmission

Under continued, low-speed operation, oil lubrication can deteriorate in a power transmission mechanism with an oil-type gear box

(gear motor) or reducer. Check with the motor manufacturer for the permissible range of continuous speed. To operate at more than

mechanism

60Hz, confirm the machine , s ability to withstand the centrifugal force generated.

 

 

 

Application to special motors

Gear motor

The allowable rotation range of continuous drive varies depending on the lubrication method or motor manufacturer.

(Particularly in case of oil lubrication, pay attention to the low frequency range.)

 

 

 

Brake-equipped motor

For use of a brake-equipped motor, be sure to connect the braking power supply from the primary side of the inverter.

 

There are different kinds of pole-change motors (constant output characteristic type, constant torque characteristic type, etc.), with

Pole-change motor

different rated current values. In motor selection, check the maximum allowable current for each motor of a different pole count. At

 

the time of pole changing, be sure to stop the motor. Also see: Application to the 400V-class motor.

 

 

Submersible motor

The rated current of a submersible motor is significantly larger than that of the general-purpose motor. In inverter selection, be sure

to check the rated current of the motor.

 

 

 

 

Inverter drive is not suitable for a safety-enhanced explosion-proof type motor. The inverter should be used in combination with a

Explosion-proof motor

pressure-proof explosion-proof type of motor.

 

*Explosion-proof verification is not available for SJ700 / SJ700B Series.

 

 

Synchronous (MS) motor

In most cases, the synchronous (MS) motor and the high-speed (HFM) motor are designed and manufactured to meet the

High-speed (HFM) motor

specifications suitable for a connected machine. As to proper inverter selection, consult the manufacturer.

 

 

Single-phase motor

A single-phase motor is not suitable for variable-speed operation by an inverter drive. Therefore, use a three-phase motor.

Application to the 400V-class motor

A system applying a voltage-type PWM inverter with IGBT may have surge voltage at the motor terminals resulting from the cable constants including the cable length and the cable laying method. Depending on the surge current magnification, the motor coil insulation may be degraded. In particular, when a 400V-class motor is used, a longer cable is used, and critical loss can occur, take the following countermeasures:

(1)install the LCR filter between the inverter and the motor,

(2)install the AC reactor between the inverter and the motor, or

(3)enhance the insulation of the motor coil.

Notes on Use

Drive

Run/Stop

Run or stop of the inverter must be done with the keys on the operator panel or through the control circuit terminal. Do not operate

by installing a electromagnetic contactor (MC) in the main circuit.

 

 

 

Emergency motor stop

When the protective function is operating or the power supply stops, the motor enters the free run stop state. When an emergency

stop is required or when the motor should be kept stopped, use of a mechanical brake should be considered.

 

 

 

 

A max. 400Hz can be selected on the SJ700 / SJ700B Series. However, a two-pole motor can attain up to approx. 24,000 rpm,

High-frequency run

which is extremely dangerous. Therefore, carefully make selection and settings by checking the mechanical strength of the motor

and connected machines. Consult the motor manufacturer when it is necessary to drive a standard (general-purpose)motor above

 

 

60Hz. A full line of high-speed motors is available from Hitachi.

 

 

About the load of a frequent repetition use

About frequent repetition use (crane, elevator, press, washing machine) , a power semiconductor (IGBT, a rectification diode, thyristor) in the inverter may come to remarkably have a short life by heat exhaustion.

The life can be prolonged by lower a load electric current. Lengthen acceleration / deceleration time. Lower carrier frequency. or increasing capacity of the inverter.

About the use in highlands beyond 1,000m above sea level

When the standard inverter is used at a place beyond 1,000m above sea level because it cool heating element with air, please be careful as follows. But please inquire for the highlands more than 2,500m separately.

1.Reduction of the inverter rating current

The density of air decreases by 1% whenever rising by 100m when the altitude exceeds 1000m. For example, in the case of 2,000m above sea level, it is {2,000(m) -Because it becomes 1,000(m)}/100(m) X {-1(%)} =-10(%), please use with 10(%) reduction (0.9* inverter rating electric current) of a rating current of the inverter.

2.Reduction of the breakdown voltage

When using inverter at a place beyond 1,000m, the breakdown voltage decreases as follows. 1,000m or less:1.00/1,500m:0.95/2,000m:0.90/2,50 0m:0.85. But please do not perform the withstand pressure test as mention of the instruction manual.

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Contents For More Precise Control Speed min When inverter is one frame size larger than motorTorque FrequencyMeets EN61800-3 2nd-Environment Frequency HzRead write Basic mode Indication only Basic Parameter Chose BasicParameter Control circuit terminals comparison tableEU RoHS compliant except solder in power module =650V, cable=100mPhase 200V class Standard SpecificationsPhase 400V class IP00 Weight lbs900HFF Rated capacity 400VGeneral Specifications SpecificationsInput terminals Unit mminch DimensionsInches for reference only ・SJ700-750, 900HFEF2, HFUF2, HFF2 ・SJ700B-900, 1100HFF SJ700-1850,2200HFE2 Model DCL-H-185-H-R 305 DCL-H-220-H-R 395 315Setting the output frequency Contents of a basic mode display.defaultFunction List 50.0 10015.00 A095 A094A294 A296B030 B028B029 B031B133 OthersB132 B134C033 C030C031 C032C150 C149C151 C1541024 135.0 Output268435455 Not available for SJ700B 25.0 100Operator, Cable OperatorOperator Terminals Main Circuit TerminalsRun Terminal Symbol Specifications 11A Contacting Maximum RateAnalog Digital DigitalAnalog ContactProtective Functions 〈How to access the details about the present fault〉〈Status Display〉 Connecting Diagram Source type logicSink type logic OperatingToConnecting to PLC Connection with Input TerminalsShielded Wire75mm2 200V 75mm2SJ700B Series / Maximum Torque with Short Time Rating Torque CharactoristicSJ700 Series / Maximum Torque with Short Time Rating Output frequency HzTherating% Derating DataSJ700/SJ700B Series / Torque Under Continous Operation Rating%Basic display mode/Data comparison function addition Those with compatibilityOption boards You can mount the SJ300 series into the SJ700 seriesD007Scaled output frequency monitoring OI-L input start frequency enableThose with compatibility Option boards External frequency filter time constMemo Application to Motors Characteristic of the motorTemperature increase MechanismHigh-frequency Noise and Leakage Current Main power supplyPrecaution for Correct Usage Lifetime of Primary Parts
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SJ700B, SJ700 specifications

The Hitachi SJ700 and SJ700B series are renowned variable frequency drives (VFDs) that represent a significant advancement in motor control technology. Designed for industrial applications, these drives offer a versatile solution for managing motor speed, torque, and efficiency in a variety of settings.

One of the main features of the SJ700 and SJ700B series is their compact design. This allows for easy installation and integration into existing systems, which is crucial for minimizing downtime during upgrades or replacements. The drives support multiple mounting orientations, facilitating applications with space constraints.

Another standout characteristic is their advanced control algorithms. The SJ700 series uses vector control technology, which optimizes the performance of both AC and induction motors. This ensures high precision in speed and torque control, making it suitable for processes that require fine adjustments. The drives also feature automatic tuning capabilities, which allow for quick commissioning while minimizing the need for extensive parameter adjustments.

The SJ700 and SJ700B series are designed with energy efficiency in mind. They utilize advanced regenerative braking technology that recovers energy, reducing power consumption and improving overall system efficiency. Furthermore, these drives incorporate energy-saving features that optimize motor operation based on load requirements, contributing to a lower carbon footprint.

These drives come equipped with robust communication capabilities. They support various communication protocols such as Modbus, Profibus, and EtherCAT, making them easily integrable with modern automation systems. This flexibility allows for real-time monitoring and control, enhancing operational visibility and efficiency.

Reliability is another hallmark of the SJ700 series. Built with high-quality components, these drives exhibit excellent thermal management and protection against overvoltage, overload, and short circuits. The SJ700B variant boasts additional features such as enhanced fault diagnostics and improved environmental protection, making it suitable for more demanding applications.

In conclusion, the Hitachi SJ700 and SJ700B series variable frequency drives stand out in terms of compact design, advanced control technologies, energy efficiency, versatile communication options, and robust reliability. These features make them an ideal choice for a wide range of industrial applications, from manufacturing automation to HVAC systems, ensuring optimal performance and cost savings for users.
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