Appliance Design - November 2007 - (Page 39)

Household Appliances (HHA) or Similar Apparatus gory Device Cate QUALITY & STANDARDS IEC 61000-4-4 Electrical Fast Transients (EFT) 4 +/- 4 kV (AC). 4 +/- 4 kV (DC). 4 +/- 2 kV (I/O’s). IEC 61000-4-5 Surge 4 +/- 2 kV Differential Mode (line-to-line). 4 +/- 4kV Common Mode (line-to-ground). IEC 61000-4-6 Conducted Radio Frequencies (RF) 4 10 V rms (AC). 4 10 V rms (DC). 4 10 V rms (I/Os). IEC 61000-4-11 Voltage Dips/Interrupts 4 Dip of 20 percent for 5 sec. 4 Dip of 30 percent for 500 ms. 4 Dip of 60 percent for 200 ms. 4 Interrupt >95 percent for 10 ms. 4 Interrupt >95 percent for 20 ms. IEC 61000-4-13 Harmonics/Interharmonics. 4 Now applicable. For clarity, a comparison of the typical to the increased severity levels can be seen in Table 1. In addition, a flowchart (Fig. 1) is also provided to assist in the process of determining applicability. A protective electronic circuit is defined in the EN 60335-1 standard as an electronic circuit that prevents a hazardous situation under abnormal operating conditions. And, an electronic circuit is a circuit with at least one component in which conduction is achieved principally by electrons moving through a vacuum, gas or semiconductor. In order to determine if an appliance has this type of circuit, one needs to find out whether there are any electronic circuits in a product that function to prevent any type of hazard. One example of where testing would be required is an electronic controller that monitors temperatures within an appliance and turns off the appropriate circuit, or the complete unit, in response to excessive temperatures. Unless the controller has been tested to these increased severity levels, which is unusual, the appliance would need to be tested to these higher levels. An appliance with switches, with an off position obtained by electronic disconnection, would also be tested to these higher severity levels. In order to determine if an appliance has this type of switch circuit, one needs to know how the off position is obtained. If a separate and isolated mechanical switch is used, then this more severe testing is not necessary, unless an electronic circuit is used to initiate and close this switch. One example of where testing would be required is a membrane switch that turns the unit off by electronically sending a signal to other circuitry. If an appliance has switches that can be placed in a stand-by mode electronically, it should also be tested to these higher severity levels. To determine whether an appliance has this type of switch circuit one needs to know how the stand-by mode is obtained. If a separate and isolated mechanical switch is used, then this more applianceDESIGN November 2007 39 No Immunity required, i.e any electronic or solid-state circuitry involved ? Yes Perform EN 55014-2 normal immunity per 2004/108/EC EMC Directive Monitoring for "Degradation of Performance" No Device uses electronic means to prevent a hazardous situation under abnormal operating conditions? Yes Perform EN 60335-1:2002, A1:2004 invoking higher immunity per 2006/95/EC LVD Safety Directive Monitoring for "Hazardous Operation:" i.e. verify electronic circuit prevents abnormal operation No Device have a standby mode? Yes Perform EN 60335-1:2002, A1:2004 invoking higher immunity per 2006/95/EC LVD Safety Directive Monitoring for "Hazardous Operation:" e.g. verify device doesn’t resume operation inadvertently. No Device have an electronic on\off switch, i.e no mechanical switch? Yes Perform EN 60335-1:2002, A1:2004 invoking higher immunity per 2006/95/EC LVD Safety Directive Monitoring for "Hazardous Operation:" e g verify no inadvertent turn on Finished Fig. 1. Flowchart assists in the process of determining which appliances may fall within the new requirements. www.applianceDESIGN.com http://www.appliancedesign.com

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Appliance Design - November 2007 Contents Editorial Shipments/Forecasts News Watch Today’s LEDs are Brighter and More Colorful than Previous Versions, Allowing Designers More Opportunities to Improve and Differentiate Their Products. When Converting from CCFL to LED Backlights in LCD Panels, New Driving Methods are Needed. Electrowetting Technology Allows Displays to be Designed in an Extensive Range of Colors. Noise Problems are Not Always Easy to Find or Fix, but Acoustic Labs Can Help Designers Ferret Out the “Good” Noise from the “Bad.” A New Sanitization Protocol for Clothes Washers Combines the Best of Three Well-Established Provisions to Ensure Efficiency, Quality and Safety. Stricter EMC Requirements Raise the Bar for Appliances with Electronic Controls and Require Testing to New Levels. Despite Added Cost and Complexity, Gas-Modulating Systems have Migrated from Large-Scale Boiler Applications to Smaller Residential and Commercial Furnaces and Appliances. A New Treatment Technology Hardens the Surface of Light Alloys such as Aluminum and Magnesium and Expands Their Potential Applications. DesignMart Advertiser’s Index Association Report: AHAM

Appliance Design - November 2007

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