Toshiba TOSVERT VF-A7 - User Manual

E6581172①
TOSVERT VF-A7/P7
The light-load high-speed operation Manual
This manual is intended only to describe the typical operation and application of the
product. The technical information contained in this manual does not guarantee the
intellectual proprietary rights or other rights of, or grant a license to, the Toshiba
Schneider Inverter Corporation or third parties, for the use of the technical information or
of the product.
© Toshiba Schneider Inverter Corporation 2003
All rights reserved.

Summary

Introduction

Function

Related parameter

Operation

Mode description

Describes the five modes for light-load high-speed operation selection via parameter F330.

Description of F330=1 or 6 (user interface) operation

Explains user interface operation using light-load detection signals for preset-speed commands.

Operation with F330=2, 4, 7 or 9 (automatic mode)

Details automatic light-load high-speed operation modes, including continuous and enabled-terminal effective types.

Operation with F330=3, 5, 8 or 10 (preset-speed mode)

Covers preset-speed mode operations for light-load high-speed function based on F330 settings.

Input;output terminal function

Input terminal function (light-load high-speed operation enabling signals 120 and 121)

Details the function of input terminals for enabling/disabling light-load high-speed operation.

Output terminal function (load detection outputs 106~109)

Explains output terminal functions for light-load and heavy-load detection signals based on F330 settings.

Light-load detection mode

Detailed description of light-load high-speed operation

Overview

1. Function Description
2. Usage Features
3. Maintenance Features

The TOSVERT VF-A7/P7 is an industrial inverter designed to enhance machine operating efficiency, particularly in applications involving light and heavy loads, such as elevators and conveyors. Its primary function is to increase motor speed during light-load conditions, optimizing performance and energy usage.

Function Description

The inverter offers a "light-load high-speed operation" function, which allows the motor to run at higher speeds when the load is light. This function is managed through a series of adjustable parameters, enabling precise control over its behavior.

Key parameters for light-load high-speed operation include:

• F330 (Light-load high-speed operation selection): This parameter determines whether the light-load high-speed operation is enabled or disabled, and specifies the mode of operation (e.g., user interface, continuous automatic, continuous preset-speed, enabled-terminal effective automatic, enabled-terminal effective preset-speed).
• F331 (Light-load high-speed operation switching lower limit frequency): Defines the minimum frequency at which the light-load high-speed operation can be initiated.
• F332 (Light-load high-speed operation load waiting time): Sets a delay before the system begins to detect load conditions for high-speed operation.
• F333 (Light-load high-speed operation load detection time): Specifies the duration over which the load is monitored to determine if it qualifies as a light load.
• F334 (Light-load high-speed operation heavy load detection time): Sets the duration for monitoring heavy load conditions, which can trigger a return to normal speed operation.
• F335-F340 (Load torque current parameters): These parameters define the thresholds for switching load torque current and heavy load torque during forward/reverse run, acceleration, and fixed speed. They allow for independent settings for different operational phases and directions.
• F341 (Automatic light-load high-speed operation frequency): Sets the target frequency for the motor during automatic light-load high-speed operation.
• F342 (Light-load detection mode): Configures how the inverter judges positive and negative torque signs for load detection, allowing for precise differentiation between rolling up/down and light/heavy loads.

The inverter uses the absolute value of torque current to determine whether the load is light or heavy. Light-load detection is performed when the operation frequency is at or above the lower limit frequency (F331) after the motor has achieved its target speed. If a heavy load is detected, or if the directed speed value falls below the lower limit frequency (F331) during high-speed operation, the light-load high-speed operation is canceled, and the inverter returns to normal directed speed frequency operation.

Usage Features

The TOSVERT VF-A7/P7 offers flexible configuration options to suit various application requirements:

• Multiple Operation Modes: Five distinct modes can be selected via F330:

  • User Interface (F330=1 or 6): In this mode, the light-load detection signal can be returned to an input terminal as preset-speed data. High-speed operation continues as long as the input frequency is maintained, even if the directed speed value falls below the switching frequency.
  • Continuous Automatic Mode (F330=2 or 7): The inverter automatically transitions to high-speed operation based on light-load detection and the automatic light-load high-speed operation frequency (F341).
  • Continuous Preset-Speed Mode (F330=3 or 8): When light-load is detected, the inverter operates at a preset high speed. The input terminal S4 can be used for other functions in this mode.
  • Enabled-Terminal Effective Automatic Mode (F330=4 or 9): Similar to continuous automatic mode, but requires an external enabling signal to activate the light-load high-speed function.
  • Enabled-Terminal Effective Preset-Speed Mode (F330=5 or 10): Similar to continuous preset-speed mode, but also requires an external enabling signal. This mode is recommended if high-speed operation needs to be stopped based on the directed speed value.

• Input/Output Terminal Functions:

  • Light-load high-speed operation enabling signals (120, 121): These signals, assignable to input terminals (F, R, ST, RES, S1, S2, S3, S4), allow external control over enabling or disabling the light-load high-speed operation, particularly useful for modes F330=4, 5, 9, or 10.
  • Load detection outputs (106-109): The inverter provides output signals for "Light-load output" and "Heavy load output." These outputs vary based on the F330 setting. In disabled mode (F330=0), simple light-load or heavy load outputs are performed after the load detection time (F333). In enabled modes (F330≠0), even if a light load is detected after a heavy load, no light-load detection output will be performed until a reset command.

• Detailed Load Detection Logic: The system calculates the average load torque current during a specified detection time (F333) after a waiting period (F332). If this average is below the switching load torque current (F335/F338), it's classified as a light load, and high-speed operation commences. During acceleration, if the load torque current exceeds the heavy load torque current (F336/F339) for a duration longer than F334, it's deemed a heavy load, and high-speed operation is stopped. Similarly, during constant speed, if the average load torque current exceeds F337/F340 for the heavy load detection time (F334), high-speed operation is halted.

• Frequency-based Control: If the directed frequency falls below the light-load high-speed operation switching lower limit frequency (F331), the inverter decelerates. If the operation frequency drops below F331, the light-load high-speed operation is reset. However, if the directed frequency is set back to F331 or higher before the operation frequency drops below F331, the high-speed operation will continue.

Maintenance Features

The manual focuses primarily on operational settings and functions, with less emphasis on explicit maintenance features. However, the detailed parameter descriptions and timing charts provide valuable information for troubleshooting and optimizing performance, which indirectly supports maintenance efforts. Understanding the various load detection thresholds and operational modes allows for precise tuning, which can prevent unnecessary wear and tear on the motor and mechanical components by ensuring the inverter operates efficiently under varying load conditions. The ability to monitor load outputs (106-109) can also aid in diagnosing load-related issues.

Toshiba TOSVERT VF-A7 Specifications