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

Operating frequency

at higher 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.

 

 

 

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

Torque characteristics

cial 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

An inverter-driven general-purpose motor heats up quickly at lower speeds. Consequently, the continuous torque level(output)

temperature increase

will decrease at lower motor speeds. Carefully check the torque characteristics vs speed range requirements.

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.

Vibration

Particularly, be 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.

 

 

 

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

Power transmission mechanism

gear box (gear motor) or reducer. Check with the motor manufacturer for the permissible range of continuous speed. To

 

operate at more than 60 Hz, 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. (Par-

ticularly 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.),

Pole-change motor

with 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.

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. Also see: Application to the 400V-class motor.

 

 

 

 

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

Explosion-proof motor

with a pressure-proof explosion-proof type motor.

 

*Explosion-proof verification is not available for L300P Series. For explosion-proof operation, use other series of motors.

 

 

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 terminals.

Do not operate by installing a electromagnetic contactor (Mg) 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 L300P Series. However, a two-pole motor can attain up to approx. 24,000 rpm, which

High-frequency operation

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 60 Hz.

 

 

[Installation location and operating environment]

Avoid installation in areas of high temperature, excessive humidity, or where moisture can easily collect, as well as areas that are dusty, subject to corrosive gasses, mist of liquid for grinding, or salt. Install the inverter away from direct sunlight in a well-ventilated room that is free of vibration. The inverter can be operated in the ambient temperature range from –10 to 50°C. (Carrier frequency and output current must be reduced in the range of 40 to 50°C.)

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Hitachi L300P manual For Correct Operation, Application to Motors

L300P specifications

The Hitachi L300P is a versatile and highly efficient variable frequency drive (VFD) known for its robust performance and reliability across various industrial applications. This drive is part of Hitachi's renowned L-series, designed to provide precise motor control and energy savings, making it a popular choice among engineers and system integrators.

One of the standout features of the Hitachi L300P is its advanced vector control technology. This technology enables the drive to deliver superior torque control and operational efficiency, which is crucial for applications requiring high performance and accuracy. The L300P's sensorless vector control capability allows it to maintain optimal performance even in varying load conditions, ensuring that motors run smoothly and efficiently.

The L300P also boasts a wide input voltage range, accommodating different voltage requirements from 200V to 600V. This flexibility makes it suitable for diverse global applications without the need for voltage converters. Additionally, the drive supports a broad range of output frequencies, allowing for seamless integration with various motor types.

Another significant aspect of the L300P is its built-in PLC functionality. This feature enables users to implement simple control tasks directly within the drive, reducing the need for external controllers and minimizing installation space and complexity. With programmable logic capabilities, users can optimize their processes and add custom functionalities to meet specific operational requirements.

The L300P is equipped with comprehensive protection features, including overcurrent protection, overvoltage protection, and motor stall prevention. These safety mechanisms ensure that the drive and the connected motors remain protected under adverse operating conditions, enhancing system reliability and reducing maintenance costs.

In terms of user interface, the L300P includes an intuitive keypad that allows for easy parameter setting and monitoring. The display provides real-time information about operational status and performance metrics, enabling users to make informed decisions quickly.

Energy efficiency is another key characteristic of the L300P. By utilizing advanced control algorithms and motor management techniques, the drive significantly reduces energy consumption, making it an environmentally friendly choice for industries looking to lower their carbon footprint.

Overall, the Hitachi L300P combines advanced technology, robust performance, and user-friendly features, making it a pivotal component in modern industrial automation and control systems. With its flexibility and efficiency, it stands out as a reliable solution for a wide range of applications, from HVAC systems to conveyor control and beyond.