Safety in medical equipment starts with power input

It is imperative that medical equipment does not pose any danger to patients or medical staff. A piece of equipment that causes a short circuit or residual cur rent can trigger a protective system upstream and in doing so shut down other, possibly life sustaining, equipment. Thus, it is necessary to pay special attention to how each unit is supplied with power. Connectors and power entry modules used in the equipment are tested to component standards and if in compliance with these standards can generally be used in most equipment without additional testing. This is especially true for medical equipment, where extensive requirements regarding safety are in effect.

Power feed

Medical devices can be connected directly to the mains or with a detachable power cord. Such plug connections must meet the requirements of Standard IEC 60320. Depending on the application, it is recommended to include a mechanism to protect against any unintentional removal of the plug from the equipment’s power socket. The most common type of protection against inadvertent disconnection is a cord retaining bracket.

Fuse holders

Permanently installed medical electrical equipment comes with its own fuses. If there is a failure in a piece of equipment, a fuse prevents that unit from tripping the circuit breaker and disconnecting other, sometimes life-critical devices, from the mains. Equipment manufacturers must ensure that energized supply leads are protected by a fuse. A few power distribution networks, however, are not polarized. That means that the power plug can be inserted in such a way that the energized conductor can be on either the plug’s left or right pole. As a result, the equipment fuse could be protecting the neutral conductor, which results in no protection against a short circuit to earth. Therefore, it is recommended that all medical electrical equipment be equipped with a double-pole fuse holder It must further be ensured that only authorized personnel can remove or replace fuses. The line switch at the power feed has an important function. Just as with fuse holders, it must be ensured that the equipment is completely disconnected from the power network after being turned off. If only one pole in a non-polarized power distribution network is interrupted, the equipment could still be live. Thus, it is preferable to use a switch that disconnects the power feed on two poles.

Power-line filters

The power-line filter is a central protective element. It protects the equipment from external HF interference and reduces the HF interference radiated by the equipment. A power-line filter is often necessary to fulfill the EMC standards for CE declaration of conformity. Because power-line filters can be under constant voltage, they are subject to strict requirements.

Y Capacitors produce a leakage current to earth whose value depends on the component’s capacitance and the power-line frequency. This fault current can, if too large, trigger the fault interrupter whereby the power supply is shut off. Thus, touch leakage current for medical electrical equipment may not exceed 100µA under nor mal conditions, and for devices with direct patient contact, it even drops down to just 10µA.

Capacitors

The capacitors used in power-line filters must meet strict cr iteria. They are wired directly between the energized conductors (X capacitors) or between the energ ized conductors and earth (Y capacitors). Common equipment standards such as IEC 60950 (IT equipment) require that capacitors between a phase conductor and the neutral conductor be at least Class X2, and capacitors between phases/ neutral and the earth conductor be at least Class Y2. For medical electrical equipment without direct patient contact (MOOP), Class Y2 capacitors to earth are sufficient; for equipment with direct patient contact (MOPP), Y1 capacitors are required. (See IEC 60601-1: 8.5.1.) Capacitors store energy corresponding to their value of capacitance. If you pull a power cable out of a power socket, the stored voltage from the X capacitors is still present on the power pins.

Increased dielectric strength is required for medical applications. An important safety aspect for achieving high dielectric strength consists of the distances between voltages. The base standard for medical electrical equipment, IEC/ UL 60601-1, specifies air and creepage distances of at least 3mm between energized parts of different polarities and 4mm between energized conductors and earth. Care is required here because various UL standards allow a smaller separation in these distances than does the IEC standards. A power socket compliant with IEC 60320 fulfills medical requirements, while sockets compliant with UL 498 do not have sufficient air and creepage distances to meet the requirements of IEC. The UL 498 standard for plugs and sockets specifies only a 1.2mm separation between energized parts of different polarities at a rated voltage of 250Vac max. In contrast, for the same components, IEC 60320 requires 3mm as does the base standard for medical electrical equipment. https://www.schurter.com

As a safety test, the base standard for medical electrical equipment specifies a high-voltage test of 1.5kVac between L and N, as well as between L/N and earth (PE). To PE, the 1.5kVac corresponds to the values of the filter standard and can be met without any problem. However, a filter between L and N should not be tested with 1.5kVac because its capacitors could be damaged. Therefore, here IEC/UL 60601-1 makes an exception for interference suppression capacitors, which can be removed for a high-voltage test if they have been tested to IEC 60384-14.

Stripping Machine Boosts Performance

SCHLEUNIGER https://www.schleuniger.com/ en-us/products/strip/wire-stripping/strip-series-b300

Strip Series B300 delivers fast and reliable stripping of cables with cross-sections from 32 to 8AWG. Repeat accuracy, mechanical precision and short working cycles ensure high productivity in common strip applications. The ergonomic machine design and revised user interface simplifies use. The portable unit opens-up completely new possibilities for fast and at the same time reliable stripping of cables with cross sections from 0.03 to 8mm2 ( 32 to 8AWG). The user interface on the high-resolution 5” color touchscreen has been revised to simplify use.

HIGH REZ SCOPE DELIVERS COMPACT, PORTABLE DESIGN

RIGOL TECHNOLOGIES

DHO800/900 series high resolution oscilloscopes are compact and portable allowing flexible use for both on-site and desktop testing. Units feature true 12-bit resolution with low noise for improved signal fidelity and analysis. Products are available in 125-250MHz bandwidths, 4 channels, 1.25GSa/sec sampling, https://www.rigolna.com/ products/digital-oscilloscopes/ dho800/

1,000,000 wfms/s waveform capture rate and 50 MPts of memory standard. Units offer 70-100MHz bandwidths, 4 channels, 1.25GSa/ sec sampling, 1,000,000 wfms/s waveform capture rate, and 25MPts of memory standard.

SEALED ANTI-VANDAL PUSHBUTTON SWITCHES OFFER LED OPTIONS

CARLING TECHNOLOGIES https://www.carlingtech.com/ pushbutton-switches-av-avh-series

AVH-Series sealed anti-vandal pushbutton switches are available with dependent LED illumination, which can be configured in one of two ways. The first is to have the ring-style LED on whenever the specified output is on. The second is to have the LED on whenever the mechanical latching switch is on. Devices are suitable for use in security panels, public transit systems, traffic signals, emergency phones, industrial controls, and marine and outdoor applications.

HIGH TEMP ADHESIVE IS DURABLE,

Loctite 402 medium viscosity, 20 gram, high temperature, durable and fast-setting instant adhesive is suitable for a wide range of substrates. Product provides reliable performance under extreme operating temperatures up to 135°C. It bonds quickly and strongly to a wide range of plastic, rubber, and metal substrates – including difficult-to-bond materials. With patented formula and reduced hazardous ingredients, product joins small parts in high-speed production applications as well as quick, on-the-go repairs. https://www.henkel-adhesives. com/sk/en/product/instant-adhesives/loctite_4020.html

Professional Heat Gun Kit Boosts Results

S-P INTERNATIONAL https://s-pintl.com/featuredproduct-steinel-heat-gun-electronics-kit/

STEINEL HG 2320 E professional heat gun electronics kit delivers cutting-edge technology and is designed for power and results. Product generates 1,600 watts of power and delivers hot air between 120 and 1,200°F. With a variety of professional grade features, gun works well on heat-sensitive objects. Product features higher durability (+20%); optimized weight balance; toggle controlled temperature change for total precision; LCD display & residual heat indicator; heat build-up warning and 4 settings.

INDUSTRIAL STT-MRAM DELIVERS 4MB CAPACITY

Everspin Technologies

EMxxLX industrial, high-density STT-MRAM product family is a high-performing persistent memory device, suitable for electronic systems where data persistence and integrity, low power - latency, and security are paramount, such as industrial IoT, network/enterprise infrastructure, process automation and control, aeronautics/avionics, medical, gaming, and FPGA configuration. The commercially available persistent memory delivers a full read and write bandwidth of 400 megabytes per second via eight I/O signals with a clock frequency of 200MHz. www.everspin.com

Modularized Data Acquisition System Comes With 3 Slots

GWINSTEK

DAQ-9600 Data Acquisition System is modularized, customizable with flexibility and precise performance. A built-in precision 6 1/2 digital DMM is the core of the unit, while the mainframe can receive up to three optional modules to match datalogging needs by choosing appropriate collection modules that make data-gathering simple, fast and reliable. Five module choices can meet tasks in R&D, product perfor- mance characteristics, system test-in, and fault diagnosis. https://www.gwinstek.com/ en-global/products/detail

Illuminated Pushbutton Switch Has Ip66 Rating

E SWITCH https://www.e-switch.com

PB66 Series illuminated pushbutton switch with an IP66 rating is easy to operate and protected against dust and strong jets of water. Illuminated and non-illuminated options are available, and it also comes with a laser etched power symbol on the round actuator.

Amazon Enters Supply Chain Arena

Global e-commerce giant Amazon has unveiled Supply Chain by Amazon, an endto-end, fully automated set of supply chain services that provide sellers with a complete solution to move products directly from their manufacturers to customers around the world. The new platform enables sellers to benefit from Amazon’s advanced logistics, fulfillment, and transportation capabilities to keep products in stock, ship faster and more reliably, and significantly lower costs.

With Supply Chain by Amazon, the firm will pick up inventory from manufacturing facilities around the world, ship it across borders, handle customs clearance and ground transportation, store inventory in bulk, manage replenishment across Amazon and other sales channels, and deliver directly to customers. Sellers can now focus on building great products for their customers and growing their business, while Amazon handles the logistics, reduces costs, and improves delivery speed.

SAMTEC OPENS CABLE, CONNECTOR FACILITY

Samtec Inc. recently opened a new manufacturing facility in Royersford PA that will specialize in the production of coaxial cables and RF connectors, serving such industries as aerospace/defense, medical de vice, datacom, automotive, computer semiconductor, instrumentation, and consumer electronics.

The state-of-the-art facility joins more than 40 other global locations. The 24,000-square-foot property is developing next-generation precision RF cable assemblies that deliver improved stability and flexure over time and address common industry concer ns of phase length, delay, loss, and shielding effectiveness.

AMD TO ACQUIRE OPEN-SOURCE AI SOFTWARE EXPERT NOD.AI

AMD has signed a definitive agreement to acquire Nod.ai, providers of open AI software. The addition of Nod.ai will bring an experienced team that has developed an industry-leading software technology that accelerates the deployment of AI solutions optimized for AMD Instinct data center accelerators, Ryzen AI processors, EPYC processors, Versal SoCs and Radeon GPUs to AMD. The agreement strongly aligns with the AMD AI growth strategy centered on an open software ecosystem that lowers the barriers of entry for customers through developer tools, libraries and models.

“The addition of the Nod.ai team accelerates our ability to advance open-source compiler technology and enable portable, high-performance AI solutions across the AMD product portfolio,” said Vamsi Boppana, senior VP, AI group at AMD. “Nod. ai’s technologies are already widely deployed in the cloud, at the edge and across a broad range of end point devices today.”