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inverters
 Introduction
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Features |
| Principles | Classifications |
| Engineering Data |
Further Information
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| Explanation of Terms | Troubleshooting |
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- inverters
PerformancePerformance
The voltage between the output terminals of an inverter.
The maximum value of a voltage equivalent to the effective value that an inverter can output at the rated input voltage.
The current that flows at the output terminals of an inverter.
The voltage frequency between the output terminals of an inverter.
An external resistor that is connected to an inverter to absorb the regenerative energy generated when a load decelerates or an elevating axis descends.
This resistor prevents overvoltage trip of the inverter.
Braking Function - Glossary of Industrial Automation">Regenerative Braking Function
The Braking Function - Glossary of Industrial Automation">regenerative Braking function uses the built-in or an external regenerative Braking circuit to decrease the internal DC voltage of the inverter by converting the regenerated energy from the motor into heat via external Braking resistors.
This function is enabled only when the inverter is connected with one or more external Braking resistors/external regenerative Braking units.
Regenerative Energy
A load connected to a motor has kinetic energy while it rotates and has potential energy while it stays in a high position. The energy that returns to an inverter when a motor decelerates or a load descends.
This phenomenon is known as regeneration, and the energy is called regenerative energy.
A fan used to cool heating components, such as semiconductors, in the main circuit of an inverter.
Harmonics
The current distortion from the normal current sine wave generated when AC is converted to DC and then smoothed.
Inverters generate harmonics, which can affect electrical equipment and peripheral devices.
Top of pageFunctions
Speed Control (ASR)
A function that controls the rotation speed of a motor.
(Automatic Speed Regulator)
Control Mode
A method to control the motor speed with an inverter including V/f control, vector control, etc.
V/f Control and V/f Characteristics
A method and characteristics of controlling a motor by applying a specific current to the coil to output a specific torque.
Refer to Principles of Introduction for details.
Constant Torque Characteristics
This setting enables the output of a constant torque based on the frequency, according to the V/f characteristics that represent the proportional relationship between the output frequency and the output voltage.
However, the output voltage is proportional from 0 Hz to the base frequency, it is constant independent of the frequency, from the base frequency to the maximum frequency. This setting is suitable for cart, conveyor, overhead traveling crane, and other applications where a torque is required, independent of the motor rotation speed.
Reduced Torque Characteristics
This setting is suitable for fan, pump, and other applications that do not require large torque at low speeds.
It provides high efficiency, reduced noise, and reduced vibration, because the output voltage is reduced in the low speed range.
Special Reduced Torque Characteristics
(Squared Reduced Load Torque Characteristics)
Characteristics that are virtually constant with the square of the speed (i.e., characteristics at which the torque generation curve is a square curve) and require a large torque at low speeds.
The maximum frequency at which a motor can generate the rated torque continuously. An inverter has 50 Hz or 60 Hz as its base frequency.
A control method that corrects the output waveform according to the voltage and current output from the inverter to an induction motor.
Refer to Principles of Introduction for details.
Sensorless Vector Control (Vector Control without PG)
Vector control with no feedback from an encoder.
Refer to Principles of Introduction for details.
Vector control with feedback from an encoder.
Refer to Principles of Introduction for details.
The time required for the output frequency to go from 0 Hz to the maximum frequency.
Deceleration Time
The time within which an output frequency is reduced to 0 Hz from the maximum output frequency.
The frequency at which the inverter starts its output when the RUN signal turns ON.
The maximum value of the frequency that an inverter can output.
An output frequency shown when the minimum value of a frequency setting signal is input (e.g., 4 mA for 4 to 20 mA input).
The condition when the frequency is lower than the minimum output frequency.
A frequency that determines the pulse-width-modulation cycle.
Set a higher carrier frequency value to reduce the metallic noise generated by the motor.
A control method that enables the torque generated by a motor to be equal to a torque reference input.
Starting Torque
The torque that is output when the motor starts.
The motor will not rotate if a load larger than this torque is applied to the motor.
A function that limits the output torque of a motor.
A function that applies a DC voltage to the induction motor for braking control (i.e., firmly stops motor rotation).
The function operates either when the motor starts or stops.
DC Braking at Startup:
DC Braking is used to stop the motor rotating by inertia without regenerative processing before starting it.
DC Braking at Stopping:
DC Braking is used if the load is large or if it will rotate by inertia and not stop with normal deceleration.
Turning OFF the power supply from the inverter to the motor by operating the protection function of the inverter against overvoltage, overcurrent, or other factors.
A function that automatically restarts a tripped inverter.
The status in which the rotor at the motor stator cannot follow the rotating magnetic field because the load applied to the motor is too large or the acceleration or deceleration is too rapid.
The motor loses speed or will be out of step.
The status in which a larger current than the rated output current flows in the circuit.
Overcurrent Suppression Function
function that suppresses the overcurrent caused by a steep current increase due to an impact load etc.
It causes the inverter to stop accelerating when the output current reaches a certain percentage of the rated current.
The status in which more than the rated voltage is applied to a circuit.
Overvoltage Suppression Function during Deceleration
A function that prevents overvoltage trip caused by the regenerative energy from the motor during deceleration.
Two options are available: Automatic deceleration while keeping the voltage rise at a certain level and starting acceleration when the voltage rise exceeds a certain level.
A status in which the power supply voltage is below the rated value.
A status in which the output torque is higher than the rated value.
A function that detects that the estimated motor output torque value exceeded the set level and output the overtorque signal.
A function that detects that the estimated motor output torque value fell below the set level and output the underorque signal.
Electronic Thermal Function
A function that prevents a motor from overloading and burning.
Motor Overload
The status in which a load that is higher than the rated torque is applied to a motor.
The status in which the inverter overload protection has been operated by an electronic thermal.
A function that enables an inverter to internally have the characteristics data of the motor and to internally perform calculations during operation to protect the motor.
A function that detects phase loss in the input power supply.
Detection is performed using the fluctuation in the main circuit's DC voltage. Detection can thus also be performed using the power supply fluctuation and unbalance or degradation in the main circuit capacitor.
A function that detects phase loss in the inverter output terminals. Detection is performed using the values of the currents flowing at the output phases.
Drive Mode
A mode in which operation commands can be received.
A unit used to operate an inverter and provide display.
A digital operator can be removed from the inverter body and installed on a control panel. It can be also used for remote control.
A reference provided by the frequency of the power supply to a motor.
A frequency reference of an inverter that is set with an analog signal.
Analog signal: A signal that expresses continuous quantities through the size of the signal. 0 to 5 V, 0 to 10 V, 4 to 20 mA, etc.
A command that stops a motor via an inverter using the digital operator or a contact input.
It enables either a free-run stop or a deceleration stop.
A function that decelerates a motor at a certain ratio until the motor stops.
Free-run Stop
A method of shutting off the inverter output to stop the motor rotation.
Executing the free-run stop function causes the motor to fall a free-run state, in which it decelerates due to the load and friction forces exerted on the motor and/or machine and comes to a stop.
Multi-function Input
The functions, such as RUN commands and STOP commands, can be allocated to the multi-function input terminals to use them.
Multi-function Output
The functions, such as a signal during RUN, can be allocated to the multi-function output terminals to output signals.
AVR (Automatic Voltage Regulator) Function
A function that has the inverter automatically compensate for the output voltage to the motor even if the incoming voltage fluctuates.
It is useful as a preventive measure against low output torque to the motor or overexcitation.
Note, however, that the inverter cannot output voltage exceeding the incoming voltage to the inverter.
Multi-step Speed Operation
A function that sets RUN speeds using multi-step speed references and switches the set speeds via external signal input.
A function that allows you to determine and fine-tune the motor stop position.
PID Control
A control method that matches a feedback (detected) value to a set target value by combining proportional (P), integral (I), and derivative (D) operations that control the flow rate, air volume, pressure, and other processes.
Proportional (P) Operation:
In this operation, the control volume is proportional to the deviation (difference between the target value and the current value).
Integral (I) Operation:
In this operation, the control volume is proportional to the time integral value of the deviation.
The P operation is less effective as the current value approaches the target value due to smaller deviation, taking a long time to reach the target value. The I operation compensates this disadvantage.
Derivative (D) Operation:
In this operation, the control volume is proportional to the percentage of change in the deviation.
Because using only the PI operation is time-consuming, the D operation is used to effectively compensate for the disadvantage in responsiveness.
Auto-tuning
A function to automatically measure and record the circuit constants of a motor, including the constants of motor coil or amount of moment of inertia.
Auto-tuning is generally used for vector control.
There are two measuring methods: measurement using a rotating motor and using a motor that does not rotate.
A frequency that is set to maintain a stable output by not changing the output frequency to within a specified frequency zone and thus avoid a resonance frequency of a machine.
Restart During Momentary Power Interruption
A function that allows selecting tripping or retrying (i.e., restarting) when the power is momentarily interrupted or there is an undervoltage.
A function that raises the output torque if it is not sufficient at low speeds.
The inverter provides two torque boost options: Manual torque boost for manual torque adjustment and torque boost - Glossary of Industrial Automation">Automatic torque boost for automatic torque adjustment.
A function that automatically controls the output voltage by detecting an output current of an inverter to increase the torque when it is insufficient at low speeds.
Automatic Energy-saving Operation Function
A function that automatically adjusts the inverter output power to a minimum during constant speed operation.
This is suitable for the load of reduced torque characteristics, such as a fan and pump.
Controlling the rotation speed of a motor.
The difference between the value of a set speed and the rotation speed of a motor.
A function that calculates the output torque from the output current to compensate the output frequency.
A function that increases the output torque when an increase in the motor load is detected.
A limit that restricts the torque during vector control if the maximum motor torque is insufficient or to prevent outputting excessive torque.
Others
A motor that rotates a rotor by means of electromagnetic induction. An induction motor uses AC to supply current to the inner coils of the motor.
The number of magnetic poles in a motor.
It is equivalent to the number of magnetic poles wound on the shaft generating torque.
Motor Ratings
The limit within which a motor can be used under specified conditions. The motor ratings include the current, voltage, torque, etc.
The torque that operates in the direction that prevents motor rotation.
The output torque of a motor. That is the moment of force generated by the rotating shaft.
The torque required for the motor to operate the load.
The load torque fluctuates according to the speed.
Load Ratio
The percentage of load current or load torque to the rated current or torque.
A value that indicates the magnetic field that is leaked to the environment or given off as heat (core loss) without generating torque. It is usually given as the inductance (coil) component that generates the magnetic field.
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