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Due to often high starting torque, heavy loads, and changing viscosities, mixing applications can be challenging. But with the right torque vector variable frequency drive (VFD) consistent batching, equipment life, and energy efficiency go hand-in hand. Let’s take a closer look at the features and capabilities that make these drives a solid choice for process mixing applications.

Starting torque: A number of factors can influence the amount of starting torque needed to get agitators in motion. The sheer volume of materials to be mixed, and their density, can place a lot of stress on vessel mixing components. Tank design also influences this – factors such as tank geometry, agitator design, baffle design and geometry, hub arrangement, motor power output, and tank temperature control all can affect the torque needed to begin a mixing cycle. And of course, batch variability also is a critical factor.

Modern vector control drives are capable of providing full torque at zero speed, which not only ensures sufficient starting power but also allows for efficient power consumption during starting. Where high torque isn’t needed, the soft-starting capability of these drives can save significant wear and tear on mixing components and gear boxes.

Mixing dynamics: […]

Today at approx. 1:03pm CST we sent about 30 old Blog posts to our email list. This was a mistake and we are sorry.

We updated our RSS Feed to include older posts and our email broadcast software perceived that the older posts were new posts and sent them to everyone.

Once again, we apologize.

Regards,
John Gierich
Administrator

Last issue, we discussed several factors which can influence the decision regarding the type of VSD – stand-alone module or packaged drive – to utilize for your application. These factors included the configuration of the drive you are seeking to replace (if this is not a new application); available space; ambient conditions in/around the installation site; and peripheral equipment to be connected to the drive.

Other factors can play important roles as well. For instance, safety and code compliance can heavily impact the VSD configuration to choose. For instance, packaged drives which are UL labeled provide assurances that the assembly is properly built, tested, and suitable for its rated output. While not all installations require UL labeling, the assurances it provides can more than offset the nominal cost for obtaining it. And while many stand-alone drives are UL labeled, a packaged unit ensures that the upstream disconnecting means, overcurrent protection, and any associated peripherals are specified and installed in compliance with applicable codes – which can translate to less work by field engineering and installation personnel.

The installation of any VSD requires properly rated disconnecting means and over-current protection installed in conjunction with the drive. (A basic VFD power wiring installation is shown in Fig. 1 below.) […]

There are a number of things to consider before deciding if a variable speed drive (VSD) is right for your application. These considerations can be roughly assigned to one of three groups: energy usage, process/application, and hardware.

Energy Usage:

 With the rising cost of electricity and increasing demands on aging power grids, there are large incentives to reduce power consumption wherever possible. According to US Department of Energy statistics, electric motors consume approximately 68% of industrial energy usage, and a significant majority of these could see energy reductions when controlled by VSDs. Couple this with the fact that nearly 96% of the total lifecycle cost of motor ownership is electricity consumed, and you can see that there can be real cost benefits to VSD use.

There are numerous sources online to assess VSD energy savings. For tools to estimate the energy savings your application might realize, go here or here.

Process/Application:

If the process or application you are considering uses a motor to drive a variable torque load (also referred to as a quadratic torque […]

January 14, 2015

Welcome to the new and improved Joliet Technologies website. This is the look of our new site.

We have converted it to a responsive site design, which means it will be viewable on all devices and the functionality and content will remain the same whatever device you are viewing it on.
It has always been our goal to have the user experience be the best possible on our website and hopefully this new design will do just that. Our new user interface allows you, in most cases and on most devices, to navigate to any page on our site with just one click.

Also we have increased the security of our site by switching to https, so whenever you are on our site anything you do is encrypted. Your connection to https://joliettech.com is encrypted with 256-bit encryption & the identity has been verified by COMODO RSA Domain Validation Secure Server CA.

All the content on our site […]

January 14, 2015

We have completed the process of re-designing our website. This will be the new look of our new site.

We have converted it to a responsive site, which means it will be viewable on all devices and the functionality will remain the same whatever device you are viewing it on.

Also we have increased the security of our site by switching to https, so whenever you are on our site anything you do is encrypted.

All the content on our site should remain the same, some pages may be updated to reflect the current status of our company and our products and services.

If you have any questions and/or comments, please feel free to contact us directly at info@joliettech.com.

The causes and effects of VFD-supplied motor shaft and bearing currents, as well as measures to counteract them, have been exhaustively covered in literature. However, as a drive and motor supplier, we frequently receive requests for information on this topic. So a summary seems in order…

Basically, shaft currents are induced because of the high frequency of the voltage pulses sent to the motor from the VFD. Recall that a pulse-width modulated VFD creates a synthesized sine wave by firing its output transistors many thousands of times per second. These pulses form high-frequency waves sent along the motor cable to the motor. Since impedance is inversely proportional to frequency, the capacitances of the cable and motor present little or no impedance to these high-frequency pulses. As a result, circulating currents can readily flow in the motor shaft. With sufficient magnitude,  and in the absence of corrective measures, these shaft currents can pass through the bearings and races to the motor frame, causing bearing pitting or “fluting” – regular, tightly spaced grooves on the bearing races – via a process referred to as Electric Discharge Machining (EDM). Ultimately, these irregularities will cause bearing failure.