Getting started

 

 

1－19

 

 



 

 

 

1 19

 

 

 

 

 

 

 

 

 

 

Introduction to Variable-Frequency Drives

 

The Purpose of Motor Speed Control for Industry

Getting

AC power to the inverter, and connect the inverter to the motor. Many applications

Hitachi inverters provide speed control for 3-phase AC induction motors. You connect

 

benefit from a motor with variable speed, in several ways:

started

ξ Energy savings – HVAC

 

ξ Need to coordinate speed with an adjacent process – textile and printing presses ξ Need to control acceleration and deceleration (torque)

ξ Sensitive loads – elevators, food processing, pharmaceuticals

What is an Inverter

The term inverter and variable-frequency drive are related and somewhat interchangeable. An electronic motor drive for an AC motor can control the motor’s speed by varying the frequency of the power sent to the motor.

An inverter, in general, is a device that converts DC power to AC power. The figure below shows how the variable-frequency drive employs an internal inverter. The drive first converts incoming AC power to DC through a rectifier bridge, creating an internal DC bus voltage. Then the inverter circuit converts the DC back to AC again to power the motor. The special inverter can vary its output frequency and voltage according to the desired motor speed.

Power

Variable-frequency Drive

Motor

Input

 

 

 

 

Converter

Internal

Inverter

L1

Rectifier

DC Bus

 

 

 

L2

 

 

U/T1

L3

 

 

V/T2

 

 

W/T3

 

 

 

The simplified drawing of the inverter shows three double-throw switches. In Hitachi inverters, the switches are actually IGBTs (insulated gate bipolar transistors). Using a commutation algorithm, the microprocessor in the drive switches the IGBTs on and off at a very high speed to create the desired output waveforms. The inductance of the motor windings helps smooth out the pulses.

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Hitachi CP-X200 －19, Introduction to Variable-Frequency Drives, Purpose of Motor Speed Control for Industry
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CP-X200 specifications

The Hitachi CP-X200 is a versatile and robust projector designed to cater to the needs of educational and business environments. It combines affordability with high-quality performance, making it an attractive option for various presentations and multimedia applications.

At the heart of the CP-X200 is its high brightness capability, with a lumen output of 3,000 ANSI lumens. This feature enables the projector to deliver clear and vibrant images even in well-lit rooms. The resolution of XGA (1024 x 768 pixels) ensures that text and graphics are sharp, making it suitable for everything from classroom lectures to corporate presentations.

One of the standout characteristics of the Hitachi CP-X200 is its advanced lamp technology. The projector uses a long-lasting lamp that can provide up to 5,000 hours of usage in standard mode, allowing for extended intervals between lamp replacements. Additionally, the ECO mode can further enhance the lamp life, extending its longevity while reducing energy consumption.

The CP-X200 is equipped with a variety of connectivity options, including HDMI, VGA, and composite inputs, allowing users to easily connect it to various devices such as laptops, DVD players, and other multimedia systems. The inclusion of USB and RS-232 interfaces ensures compatibility with different control systems, making it a flexible choice for diverse setups.

Another significant feature is the projector's built-in 10-watt speaker, which provides decent audio output, eliminating the need for external speakers in smaller venues. The speaker system enhances presentations, ensuring that audio and visuals are cohesive, promoting better audience engagement.

Portability is another key aspect of the Hitachi CP-X200, which weighs just around 3.5 kg (approximately 7.7 lbs), allowing for easy transport between locations. Its compact design makes it suitable for both fixed installations and mobile use, catering to professionals who require a projector that adapts to various environments.

The user-friendly interface and robust remote control enhance the projector's operability, providing easy access to essential functions. Additionally, features such as auto keystone correction adjust the image to maintain consistent quality even when the projector is not perfectly aligned with the screen.

In summary, the Hitachi CP-X200 is a feature-rich projector that embodies reliability, performance, and ease of use. Its combination of high brightness, various connectivity options, long lamp life, portability, and integrated audio makes it an excellent choice for education and business professionals seeking a dependable presentation solution.
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