Drives and Control Solutions

Motors, Control Solutions, Power Transmission and Advanced Motion Technology                                                                 

October 19, 2020

In this article, we will discuss a KEB drive feature called Voltage Stabilization.  This post is part of a series that highlights different KEB drive features and how they can be utilized to optimize motor performance. Previous post topics include:


Input Voltage determines VFD Output Voltage

One of the many benefits of using a variable frequency drive (VFD) to control an electric motor is the ability to adjust the voltage output to the motor for optimal efficiency.

A VFD rectifies the AC input voltage to a DC voltage across the DC bus capacitors. The VFD then uses a PWM output to convert this DC power into an AC output to the motor.

When operating the VFD in an open loop mode, the output voltage and frequency is based on a defined Volt/Hz curve in the VFD. The available AC voltage output of a VFD is dependent on the DC bus voltage level. And the DC bus level is dependent on the AC input to the VFD.

87Hz-Motor-Characteristic-Graph-1-1536x862.png

Thus, any fluctuation in the AC input voltage may cause the output voltage to the motor to fluctuate as well. Normal voltage deviation from the nominal input usually does not result in any noticeable effect on motor performance.  However, extreme voltage variations to the motor (undervoltage or overvoltage) can cause extra motor heating and premature failure.

In the cases where large input voltage fluctuations may occur (weak mains, generator power), having the ability to stabilize the output voltage to the motor independent of the input AC main fluctuations, allows the system to run more efficiently and increase the lifetime of the motor windings.

What is Voltage Stabilization?

And when should I use it?

KEB VFDs incorporate a function called Voltage Stabilization into the parameter settings which allows the VFD to stabilize the output voltage to the motor based on the motor requirements.

An example when Voltage Stabilization would be used is if a motor has a rated voltage lower than the input voltage to the drive. The KEB VFD is designed for an input voltage range of 480±10%. Thus, the input voltage may be up to 528VAC. An input voltage near the top end of the voltage range can happen on a voltage system with weak mains.  Maybe the voltage level is closer to nominal while the mains system is loaded, but the voltage can increase when the overall line load is reduced. A typical scenario is when a high voltage fluctuation happens during the evening when most machinery has been turned off.

In this case, if the motor rated voltage is 460VAC (60Hz) and there is no stabilization of the output voltage, when the input voltage increases, this can effectively increase the Volt/Hz curve slope which would increase the output voltage to the motor at a given output frequency. The sub-optimal higher voltage would result in higher motor current which leads to increased motor heating. The increased current and heat can have a negative impact on the lifetime of the motor windings and the performance of the motor.

Voltage-stabilization-example-graph.png

The KEB Voltage Stabilization function allows the user to define what the output voltage to the motor will be at the rated output frequency. The Voltage Stabilization function then keeps the output voltage to the motor fixed to the proper Volt/Hz curve independent of any input voltage fluctuations, and consequently DC bus fluctuations in the drive.  In the case where the input voltage increases above the rated voltage of the motor, the KEB VFD Voltage Stabilization function keeps the voltage output to the motor limited to the Volt/Hz curve based on the entered values in the KEB VFD.

Enabling Voltage Stabilization results in an optimal V/Hz curve even during situations with a high input voltage to the drive.

In the example case above (Figure 72), the output to the motor is set to 460VAC at 60 Hz. Without the voltage stabilization activated, the output to the motor would be increased by the ratio of the input voltage to the rated voltage of the motor. In this case, it would be increased by a ratio of 528VAC/460VAC = 1.15. So if the motor was running at 30 Hz, the output voltage should be 230VAC. Without the voltage stabilization, the output voltage to the motor would be 230VAC*1.15 = 264.5VAC.

The same situation above occurs when running a motor rated at lower voltages than typically found in the United States. For example, a European motor rated at 400VAC/50Hz or 380VAC/60Hz. In this case, the voltage stabilization function allows the user to limit the output voltage at the specified frequency to match the Volt/Hz curve of the motor being controlled by the VFD.

Performance Results

Voltage-stabilization-Accelleration-with-Load.png

When the KEB VFD Voltage Stabilization is activated, the Volt/Hz curve for the motor is defined in the VFD software. If the input voltage drops below the rated voltage of the motor, the VFD will still follow the correct Volt/Hz curve until the output voltage limit is reached. When the required output voltage to the motor equals the input voltage, the output voltage to the motor will remain at this level. If the Voltage Stabilization is not activated, a reduction in the input mains voltage would result in the slope of the Volt/Hz curve being reduced which would result in a lower than required voltage at the motor terminals. The lower voltage can result in increased current and heating of the motor and reduced motor performance.

Deceleration-of-high-inertia-drive-graph.png

In this case (Figure 73), the use of Voltage Stabilization results in lower current utilization.

Voltage stabilization provides an optimal voltage output, especially with overhauling loads (see Figure 74).

Improve Motor Shaft Performance

By utilizing the KEB VFD Voltage Stabilization function, applications can be set up to run at the highest efficiency possible. Increasing motor performance and lifetime allows machine builders and end users to get the most out of their investments.

Source


Editor's Pick: Featured Article


Motor Disconnect SwitchesMotor disconnects are more than simple on-off devices to satisfy lockout-tagout requirements. They have become an integral part of the motor control circuit as disconnects increasingly offer control functions, such as auxiliary contact interface, added selector switches and push buttons.

Disconnects can be fusible or non-fusible and can have different pole arrangements and environmental ratings. Multiple disconnects can be packed into one enclosure, saving space and cost while allowing you to address varied requirements, including harsh food processing or washdown applications.

Read More


 

Advanced Sensing Solutions for Cost-Effective Machine Building

Omron IOLinkSensing technology has a major presence in manufacturing machinery. It provides the foundation for maintaining consistent quality and detecting any lapses in machine performance. If subtle changes in the physical properties of a machine can cause it to fail, then the sensors responsible for detecting those changes can save manufacturers lengthy downtime and repair costs.

In addition to helping cut maintenance costs, sensors also present an opportunity to make the machines more cost-efficient. Whether through their resistance to harsh chemicals or their ability to reduce the overall machine footprint, the right sensors can make a huge difference. 

Read More

 

Product News

  • Prev
The New eSMART Series HMI products from Exor combine state-of-the-art features and top performance ...
The VLX-60 is a new member of the VLX series of Electric Encoders a product line based on Netzer ...
Siemens presents the Simatic Robot Library for the Simatic Robot Integrator - a new universal robot ...
With Sinamics PCS, Siemens presents a new power conversion system for battery storage applications. ...
With “Control Panel Design” Siemens Smart Infrastructure has integrated new electrical planning ...
Having the ability to effectively inspect, diagnose, and document trouble spots is crucial for ...
Advancing gripping technology is essential for promoting new uses for automated systems. Festo’s ...
Yaskawa Solectria Solar has joined the Tigo Enhanced initiative, aimed at providing customers with ...
Toshiba Industrial Products Canada (TIPCA), a wholly owned subsidiary of Toshiba International ...
Hatch has recently launched an all-in-one software called PneuCalc 7.0.0 that will enable engineers ...

New Product


Flir Thermal and Visible VideoscopeFLIR Systems, Inc. recently announced the FLIR VS290-32, an industry-first, videoscope that combines thermal imaging and a visible camera specifically designed for safer and more efficient.

inspections of hard-to-reach underground utility vaults. The VS290-32 is the company’s first industrial-grade, electrical safety-rated, flexible dual-sensor videoscope on a replaceable, two-meter-long camera probe. For use in the most demanding environments, the VS290-32 is CAT IV 600 V safety rated for electrical inspections, along with an IP67-rated camera tip and IP54 base unit to protect against dust and water. 

Read More


 

Latest News

  • Prev
The solution will mitigate the environmental impact of building a major dam and hydroelectric ...
In May 2020, ABB’s Motion business area announced that it was reviewing how it served customers in ...
The 18th annual Motor & Drive Systems 2021 virtual program has been unveiled.
Yaskawa, a manufacturer of motion control, robotics, and variable speed drives and Phoenix Contact, ...
PC-based control and TwinCAT provide a foundation for advanced Industrie 4.0 and Internet of Things ...
Join ABB for an in-depth look at how variable frequency drives assist in aeration applications for ...
Leading Canadian forest product company, Chantiers Chibougamau, has selected ABB to help overhaul ...
ABB Motion Canada alongside our HVAC Partners nationwide has introduced a special program for our ...
Brock Solutions is pleased to announce the recent award by the Region of Peel of the Clarkson and ...
Kerrwil Publications Great Place to Work. Certified December 2019 - December 2020

538 Elizabeth Street, Midland,Ontario, Canada L4R2A3 +1 705 527 7666
©2020 All rights reserved

Use of this Site constitutes acceptance of our Privacy Policy (effective 1.1.2016)
The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Kerrwil