Risks for electrical equipment in installations are often only noticed by listening carefully.
This is also the case here, although it is not uncommon in the metalworking industry. The cause of the extreme voltage distortions shown above in a broad frequency spectrum up to slightly above 20 kHz are powerful converters in the presses. A common disturbance pattern is disturbingly loud whistling tones in open circuit breakers, through which the largest proportion of the causing clock frequency currents must flow. Rightly Read more
https://i0.wp.com/pq-as-a-service.com/wp-content/uploads/2020/11/singende_leistungsschalter.png?fit=1477%2C691&ssl=16911477Frank Strobelhttps://pq-as-a-service.com/wp-content/uploads/2025/08/Icon_PQ_knowledge.jpgFrank Strobel2020-11-25 13:23:502021-01-26 15:20:46Singing circuit breakers in the metalworking industry
Potential equalisation currents, often referred to as vagrant currents, are not only a problem in industrial plants. Currents can also have a disruptive effect on equipotential bonding in commercial and even residential buildings.
Cause: Leakage currents frequency inverter
The picture shows the cause of an annoying whistling in the speakers of a home stereo system. These are leakage currents of an inverter drive that must flow back to the transformer star point due to their characteristics. They always occur when a corresponding filter on the inverter is missing or defective. Common-mode voltage distortions of the phase-to-earth voltages then occur at the clock frequency at the inverter output. These clock frequency currents are then detectable at the equipotential bonding of the entire building and also at the disturbed audio system.
Solution
Retrofitting and EMC-compliant installation of an effective filter.
Impressum
PQ Professionals GmbH
Landsberger Straße 4
04157 Leipzig
vertreten durch den GF Dipl.-Ing. (FH) Frank Strobel
https://i0.wp.com/pq-as-a-service.com/wp-content/uploads/2020/11/Stereo.png?fit=400%2C250&ssl=1250400Sascha Engelhttps://pq-as-a-service.com/wp-content/uploads/2025/08/Icon_PQ_knowledge.jpgSascha Engel2020-11-23 14:09:482021-01-26 15:20:17When the audio system whistles
The topic of power quality is rapidly gaining importance in the context of the energy transition and smart grids and smart metering. As a result, the question marks of the supposedly affected and involved parties are piling up to the same extent. What does this mean for the distribution grid operator, the authorities, the industrial companies, the electrical inspectors, the electrical contractors, the professional associations, the infrastructure companies such as airports, railways, etc.?
Bringing more light into the dark
For stakeholders, whether already familiar with the topic of power quality today or not, the new Read more
https://i0.wp.com/pq-as-a-service.com/wp-content/uploads/2020/11/xxxx-1.png?fit=2704%2C1069&ssl=110692704Sascha Engelhttps://pq-as-a-service.com/wp-content/uploads/2025/08/Icon_PQ_knowledge.jpgSascha Engel2020-11-13 15:03:012021-01-26 15:19:29PQaaS: The Power Quality as a Service website goes live
Certified power quality monitoring and fire protection enhancement
Preamble
The volume of digital data continues to increase rapidly and steadily. Not least caused by cryptocurrencies, such as Bitcoin (XBT), Ether (ETH), Litecoin (LTC), etc. or, for example, by the blockchain process, a quasi-type database that works on various networked servers. The increasing demand for data exchange also increases the need for data centres, which are planned, built and maintained on a large scale globally. However, data centres in the electrical energy context are subject to complex challenges that can influence (legally) secure 24/ operation.
The basic requirements
When planning the energy supply of a data centre, many demands must be taken into account:
Secure location in terms of energy supply and environmental conditions
High energy efficiency to minimise operating costs
Maximum availability (Uptime Insitute Tier 1-4) through use of redundancies, e.g. UPS, generators
High security (fire protection, access, defence against cyber attacks)
System stability and reliability of the operating resources used
Scalability
The problem description
Various studies show that power quality problems cost billions each year. Read more
Data centres are not only found in stand-alone form around the world, but are also found in many other sectors. These include banks, insurance companies, industrial enterprises, hospitals, airports, energy suppliers, public authorities, etc. It is not only the enormous energy demand that poses major challenges for data centre operators and energy suppliers. Additional factors that can lead to ad-hoc problems and serious damage are coming more and more into focus.
Investment in more security for 24/7 operation
As listed in this use case, HuiShang Bank Hefei / Anhui Province in China has chosen to invest further in Read more
In a large urban city, the technology for supplying fresh water is getting old. Although the pumping stations and the infrastructure are in good condition, the maintenance and repair costs are continuously and extremely increasing. Electrical monitoring of the entire system is only available to a limited extent, and if so, only partially. Read more
https://i0.wp.com/pq-as-a-service.com/wp-content/uploads/2020/10/Frischwasser.png?fit=785%2C333&ssl=1333785Sascha Engelhttps://pq-as-a-service.com/wp-content/uploads/2025/08/Icon_PQ_knowledge.jpgSascha Engel2020-10-27 13:54:032021-01-26 15:16:30System for power quality, energy management and pump automation
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Problem: Potential equalisation currents