May 2023 - MH&W

The Career of Marge Janitschek at MH&W

May 19, 2023 6:03 am Leave a Comment

In April 2023, Marge Janitschek, purchasing manager at MH&W International Corp, celebrated 50 years with the company. As part of a recent Q&A session, Marge shared details about her current position and how her role and the industry have changed over time.

When did you begin working at MH&W?

I joined MH&W back on April 30, 1973.

What does your current role involve?

Right now, I’m responsible for purchasing and supply line management with approximately 10 vendors located in Europe and Asia. These vendors fall under three divisions of MH&W: cores and components, filters and TIM, and gaskets and seals. I’m also involved in receiving operations, as well as entering and processing purchase orders and material transfer orders for value-added orders.

What does a typical day look like for you?

A usual day for me consists of:

Checking the vendor portals for stock availability and in-transit items
Entering new parts into the software databases
Entering and sending purchase orders to vendors
Updating new incoming delivery dates for all open POs
Tracing the whereabouts of in-transit products
Optimizing minimum and maximum inventory levels based on input from the sales division about future use and product history
Replying to customers asking for compliance forms for specific parts, such as RoHS, REACH, etc.

How has your role changed since you started at MH&W?

The most dramatic change was that, starting in order processing, I’ve seen and lived through the transition from manual entries to digital platforms. On average, a manual order took three days to enter, process, and ship, while now an order can ship within the same day. After five years in order processing, I transitioned to inventory maintenance, in which a computer system for purchasing was installed and greatly improved our lead times. From inventory management, MH&W promoted me to purchasing manager, the position I hold today.

Is there anything else you would like to share regarding your experience at MH&W?

MH&W was and is a great place to work, and I’ve experienced the evolving changes in the world and the work environment. New skills were developed and required to keep up with the automation and digitalization of almost all business processes. This is an endless learning process.

I’ve witnessed the evolution of technology in my lifetime. For example, when I started at MH&W, I was working in collaboration with several research facilities, such as Lawrence Livermore and Brookhaven, to provide very large, soft magnetic ferrite rings to create and harness the potential power of fusion. Now, after my 50 years of service and the observation of research and experimentation results, fusion reactors are closer to becoming a reality.

Technology has moved me from an analog to a digital world. In the 1970s, Bell Telephone Labs developed the ability to switch the telephone system from analog to digital. All central switching stations in telecommunications and telephones were converted to digital communication from rotary touch-tone telephones. I was part of the transition in handling the tremendous amount of ferrites used by AT&T, later called Lucent, Northern Telecom, and others.

Also, there’s the commercialization of the cell phone. As part of MH&W, I was instrumental in procuring and selling large amounts of microwave components imported from TDK in Japan for the development of cell phone networks for Motorola and GE.

Learn more about MH&W

Since MH&W’s beginnings in 1964, the company has developed into an industry leader in high-performance nanocrystalline components, magnetic cores, power conversion parts, and noise-filtering and EMI-prevention solutions. Our team of experienced engineers serves clients across North America with inductive and line absorbers, filters, and chokes for EV, VFD, solar, and wind applications. Our goal is to deliver standard and custom products that help our clients be competitive in their various markets. To learn more about MH&W and our capabilities, contact us today.

3 Shaft Grounding Alternatives to Help Protect VFDs

May 18, 2023 2:59 am Leave a Comment

As the demand for automation and energy efficiency increases, many facility managers, building owners, and engineers are switching to variable frequency drives (VFDs). These solutions are among today’s most sustainable technologies, enabling motors to function at reduced speeds without sacrificing torque. VFDs ultimately work to reduce power consumption in electric motors, saving at least 30% in energy costs. At the same time, VFDs often need more protection than other systems.

Common-mode currents induced by VFDs may cause electrical discharge machining (EDM) that can damage electric motor bearings, shortening their service life and compromising the system’s reliability. Many rotational machines like pumps, generators, and motors use shaft grounding rings to mitigate this issue. These rings allow for easier grounding of electrical currents that would otherwise build up on the machine’s rotating shafts, preventing subsequent fluting and pitting on the bearings’ raceways.

The grounding ring channels electrical currents along a ring and brush, redirecting them away from the bearings. In theory, shaft grounding rings effectively reduce voltages, but only until they are contaminated by grease or dust. In addition, the rings don’t reduce the damaging currents—they only divert them to the ground grid, where these currents create electrical EMI issues with any electronic device, such as relays and sensors connected to the same electrical grid.

Although grounding rings may help protect motors from damage, there are some other alternatives available, but only one that is the most effective: Nanotech^® common mode choke cores.

Alternatives to Grounding Rings

The alternatives to grounding rings include shielded cables, insulated bearings, and common mode chokes. Unfortunately, shielded cables and insulated bearings have their own pitfalls as with the grounding ring, leaving the common mode core choke as the best alternative to solving common mode current issues.

Shielded Cables

One alternative to grounding rings is to run shielded cables from the VFD to the motor. The shielded cable acts as a Faraday cage, effectively isolating the VFD and motor from the external environment by providing a direct ground path back to the VFD. Unfortunately, the shielded cable is usually not connected properly, which negates the shielding on the cable. In addition, shielded cables add an extremely high cost to the VFD/motor system. In instances where standard cables are buried beneath the floor, replacement is usually not an option.

Insulated Bearings

Another alternative to grounding rings is to install ceramic insulated bearings, which form a high-impedance electrical barrier for damaging electrical currents, protecting bearings and motors.

As with grounding rings and shielded cables, there are many problems associated with insulated bearings. First is the cost. These bearings cost significantly more than traditional bearings, and they still require maintenance and must be replaced periodically. Secondly, the insulated bearing does nothing to reduce the common mode currents. It only traps the motor’s common mode currents, allowing them to circulate and cause excessive heating in the windings. Finally, the common mode currents can eventually overcome the insulation within the bearing and destroy the bearing.

Common Mode Chokes

The most effective alternative to shaft grounding rings is Nanotech^® common mode chokes. By installing Nanotech^® common mode chokes around the VFD’s output conductors to the motor, the damaging high-frequency common mode current is absorbed in the source of the noise (VFD’s IGBT/SiC/GaN switching) well before the damaging currents reach the motor. As with the other solutions, these common currents are absorbed instead of redirected or blocked.

Advantages of Nanotech^®Common Mode Chokes

There are several advantages to using Nanotech^® common mode chokes over traditional alternatives. Some of the most notable advantages include:

Improved Performance: Nanotech^® common mode chokes provide superior filtering performance, reducing EMI and improving signal quality. In addition, Nanotech^® common mode chokes are the only solution that reduces conducted and radiated EMI interference that affects relays, sensors, and other electronic devices connected to the electrical grid. This becomes extremely important when unshielded cables are used.
Installation: Installation can be done in less than an hour, eliminating long downtimes associated with the other alternatives.
Higher Reliability: Nanotech^® common mode chokes are a permanent, no-maintenance lifetime solution, unlike all the other alternatives. Because they do not rely on physical contact with the shaft, common mode chokes are less susceptible to wear and tear and can provide longer service life.
Cost-Effective: Common mode chokes are typically less expensive than traditional grounding rings, making them a cost-effective solution for improving system performance.

Why treat an electrical problem with a mechanical device when the electrical solution of Nanotech^® Common Mode Chokes is readily available?

Innovative Nanotech^® Cores From MH&W

You can prevent common mode currents from causing damage or interference to your VFDs, allowing for efficient and cost-effective operation. Choose Nanotech^® to reduce electrical noise and ensure your high-power inverter systems continue working as they should. Contact MH&W for more information.

5 Tips for Reducing Electromagnetic Interference (EMI) in VFDs

May 2, 2023 12:58 pm Leave a Comment

Variable frequency drives (VFDs) are widely used in industrial applications to control the speed, start-up, and torque requirements of electric motors. However, VFDs can produce electromagnetic interference (EMI) that can cause problems with other electronic equipment in the vicinity.

Electromagnetic interference, called EMI, is unwanted electrical noise that prevents electronic systems from performing as intended. EMI occurs when an electromagnetic field causes disruptions in the radio frequency spectrum of a communication, analog, or digital electronic system. Since EMI can cause devices to operate poorly and, in some cases, to stop working completely, learning how to reduce electromagnetic interference is very important.

As industry experts with over 50 years of experience, MH&W International Corp. offers reliable solutions for reducing electromagnetic interference in variable-frequency drive systems (VFDs). While our choke products provide a simple and cost-effective method of eliminating high-frequency noise, there are other steps you can take to reduce EMI.

Here are five tips for reducing EMI in VFDs:

Proper grounding: Proper grounding is essential for reducing EMI. Ensure that the system’s VFD and all other electrical equipment are properly grounded according to local codes and standards. One of the first steps to reduce EMI is to properly ground the VFD and other components. Since high-frequency EMI travels on a conductor’s surface, selecting a braided conductor provides increased surface area and a lower resistance path for noise to travel to the ground. Instead of using a solid conductor, consider a multi-strand option.
Shielding: Shielding can help reduce EMI from VFDs. Use shielded cables for power and signal connections and ensure the shields are grounded properly.
Proper wiring: Proper wiring can reduce EMI. Keep the wiring as short as possible and avoid running it parallel to other wiring or metal surfaces. Use twisted pair wiring for control signals. Shielded cables effectively minimize the effect of capacitively coupled EMI between two cables that run parallel to one another. To accomplish this, the shielding must be grounded only at one point: at the noise source or the panel. However, for high-frequency noises above 1 MHz, it’s better to ground the shield at both ends. This method is also applicable to analog cables. High-power DC voltage cables, motor cables, and other lines should be spaced out by at least eight inches when placed parallel to prevent high-frequency couplings. Taking this precaution will be very helpful in preventing signals from coupling with one another and generating noise.
Filtering: Filtering can help reduce EMI. Install filters on the input and output of the VFD to suppress the high-frequency noise. If EMI generation is unavoidable, the next best step is mitigating it at the source or preventing it from entering the system. To achieve this, mount AC line filters on either the grounded frames or the backplane during the design phase. This will prevent EMI from entering the system.

Since input line side cables also produce noise, minimize it by routing input power cables as far as possible from output power cables and other cables in the circuit. Additionally, the AC power’s length should be reduced, and the filter should be properly grounded and installed near the source of EMI.

Distance: Increasing the distance between the VFD and other electronic equipment can also help reduce EMI. If possible, locate the VFD in a separate enclosure or room.

Install Nanotech^® Cores at the Inverter Output

Out of all the previously discussed methods for reducing EMI, proper wiring is the most effective method; if combined with Nanotech^® cores, it is the most simple and effective solution. MH&W Nanotech^® products are common mode toroidal cores made with nanocrystalline material that eliminates high-frequency noise at the source.

Our Nanotech^® cores are so effective that unshielded cables can replace shielded cables, reducing the system’s overall cost. Other key benefits of Nanotech^® cores include:

Effectively reduces radiated emissions
Maintenance-free
Long service life
Easy to install and compatible with existing drive setups
Highly effective in drive systems with long cable runs

The Nanotech^®’s magnetic core captures and absorbs high-frequency currents, eliminating unwanted noise. These products are very beneficial in conducted or radiated EMI applications and unlike filters, Nanotech^® cores have no passive elements, resulting in low losses.

Why Choose MH&W

Reducing electromagnetic interference is critical for any type of VFD. While there are many steps you can take to protect your equipment, installing Nanotech^® cores is the most effective and long-lasting solution. MH&W specializes in providing innovative technology for VFD motor installations. Our products are used globally by major OEM VFD manufacturers and end users to ensure their equipment properly functions.

With engineering and sales operations throughout the U.S., Mexico, and Canada, MH&W International supports the power supply and telecommunications industries with thermal interface materials, powder cores, and other products and services that promote our customers’ long-term goals.

MH&W International is a leading supplier of magnetic components with over 55 years of experience in the industry. Here are some reasons why you may choose MH&W:

Quality: MH&W only sources materials and components from reputable manufacturers to ensure consistent product quality. We also have rigorous quality control processes to ensure that all products meet or exceed customer expectations.
Technical expertise: MH&W has a team of experienced engineers knowledgeable in magnetic materials and their applications. We can provide technical support to customers and help them select the best products.
Customization: MH&W offers customization services to tailor standard products to customers’ requirements. We can modify products such as cores to meet unique specifications.
Global reach: MH&W has a global reach, with sales and distribution centers in North America, Europe, and Asia. This allows us to serve customers worldwide and provide local support in different regions.
Competitive pricing: MH&W strives to offer competitive pricing while maintaining high-quality standards. We have long-standing relationships with our suppliers, allowing them to negotiate favorable pricing for our customers.

Overall, MH&W is a reliable supplier of magnetic components with a strong commitment to quality, technical expertise, customization, global reach, and competitive pricing.

We offer a comprehensive range of choke products, including:

To permanently resolve your EMI and VFD motor problems, contact our team today.