[PSES] Cooling fan safety query

This is a question for the safety testing engineers. We have products that contain 12V/24V DC cooling fans that cool either the PSU or processing circuits. The fan speeds are reduced with basically a series resistor to reduce audio noise. The safety testing agency demands to know the exact

Re: [PSES] Cooling fan safety query

In message 80f690de07894e049b221728b4a99...@dbxpr07mb206.eurprd07.prod.outlook.com , dated Fri, 13 Dec 2013, McBurney, Ian ian.mcbur...@allen-heath.com writes: We have to use alternative fans due to supply issues and this incurs considerable test agency costs as the agency won?t accept a

Re: [PSES] Cooling fan safety query

John; I believe the fans are listed for the flammability of the plastic body but I may be wrong. Ian McBurney Design Compliance Engineer. Allen Heath Ltd. Kernick Industrial Estate, Penryn, Cornwall. TR10 9LU. UK T: 01326 372070 E: ian.mcbur...@allen-heath.com -Original Message-

Re: [PSES] Cooling fan safety query

In message ed08bb5be2d841e0a1b0ca499f924...@dbxpr07mb206.eurprd07.prod.outlook.com , dated Fri, 13 Dec 2013, McBurney, Ian ian.mcbur...@allen-heath.com writes: I believe the fans are listed for the flammability of the plastic body but I may be wrong. It would surely be worthwhile to check

Re: [PSES] Cooling fan safety query

Hi Ian, The last company I was with used to specify a single manufacturer's fan in the UL report including supply voltage / current / CFM) and then (with UL's agreement) include the words or any recognised equivalent component. During the factory inspections, if a fan was being fitted from a

Re: [PSES] Cooling fan safety query

Ian I think the critical factor may be the airflow rates at the reduced voltages as this may well vary between various ostensibly similar fans of the same nominal voltage. The actual airflow patterns from the outputs of the various fans may also differ due to differing blade profiles, etc.

Re: [PSES] Cooling fan safety query

John; I agree the airflow rates will vary with applied voltage and blade profile but if the product continues to function safely with a stalled rotor why does it have to be listed in the critical component list. Regards; Ian McBurney Design Compliance Engineer. Allen Heath Ltd. Kernick

Re: [PSES] Cooling fan safety query

Ian That's a very good question! The only other things that I can currently think of are: - The agency does not (want to?) accept the UL Recognition (not Listing, I suspect) for business political reasons because UL is a competitor (and AFAIK, there is no compelling legal reason why they have

Re: [PSES] Cooling fan safety query

In message ff0018ae2af54a2b95bfa760f8747...@dbxpr07mb206.eurprd07.prod.outlook.com , dated Fri, 13 Dec 2013, McBurney, Ian ian.mcbur...@allen-heath.com writes: but if the product continues to function safely with a stalled rotor why does it have to be listed in the critical component list.

Re: [PSES] Cooling fan safety query

John; I have often asked for the reasoning to many similar problems and get directed to an ambiguous clause in the standard that I read one way and the agency reads the other way and because there is no independent arbiter I end up acquiescing as the whole process slows down and I am on a

Re: [PSES] Cooling fan safety query

A locked rotor test is considered an abnormal and measured temperatures are allowed to exceed the limits for normal operation. If that happens, then it proves a minimal amount of airflow is required to maintain safe temperatures and minimal CFMs become required. That said, I've never seen a

Re: [PSES] Cooling fan safety query

In message c8225bb6612e4cf382ba4b073e71d...@dbxpr07mb206.eurprd07.prod.outlook.com , dated Fri, 13 Dec 2013, McBurney, Ian ian.mcbur...@allen-heath.com writes: I have often asked for the reasoning to many similar problems and get directed to an ambiguous clause in the standard that I read one

Re: [PSES] Cooling fan safety query

Agreed on both counts! John Allen Sent from my Fonepad "Brown,William" wrote:>A locked rotor test is considered an abnormal and measured temperatures are allowed to exceed the limits for normal operation. If that happens, then it proves a minimal amount of airflow is

Re: [PSES] [External] Re: [PSES] Cooling fan safety query

Additionally, most agencies have a process to repeal or elevate a decision beyond the engineer that you are directly working with. Josh -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Friday, December 13, 2013 8:53 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject:

Re: [PSES] Cooling fan safety query

Will is correct. I have gotten around this type of fan issue in the past by simply running the normal heating test with the fan disconnected. If you can pass normal temperature rise limits without the fan then your argument becomes easier as the fan is no longer critical, it is simply a

Re: [PSES] Cooling fan safety query

Ian It doesn't function safely with the stalled rotor, it functions not dangerously. In fact the standard doesn't really care whether it functions, just whether it's unsafe. Do you need the fans to meet maximum temperature limits in normal operation, or just to lower temperatures and prolong

[PSES] WEEE Directive - user information

Article 14 of the new WEEE Directive requires manufacturers to provide information to product users on the process and benefits of dealing with WEEE in accordance with the Directive (as opposed to just thowing it away with other household waste). This requirement is not new - it was

Re: [PSES] Cooling fan safety query

Ian - Another consideration, since you have more than one fan, is that you can disable *all* fans simultaneously to demonstrate that no cooling is necessary for safety reasons. This is a multiple fault scenario, but it's at your discretion to do so to prove your case and eliminates the need for

[PSES] DC Boat Motor

Hi Group, I am a bit confused about what standard may apply for DC powered Boat Motor. I am being told that EN55012 applies. I am not convinced. Thoughts? Thank you , Mark Schmidt - This message is from the IEEE Product Safety

Re: [PSES] DC Boat Motor

Hi Mark, One more clarification please. Is this for a Toy Boat, either remote controlled or otherwise? Or is it something like a tolling motor for a real boat? thanks, –doug Douglas E Powell doug...@gmail.com http://www.linkedin.com/in/dougp01 From: Mark Schmidt Sent: Friday, December

Re: [PSES] DC Boat Motor

In message 119fa9545c6e264b830c4582886d11908871b...@quimby.dw.local, dated Fri, 13 Dec 2013, Mark Schmidt mark.schm...@dornerworks.com writes: I am a bit confused about what standard may apply for DC powered Boat Motor. I am being told that EN55012 applies. I am not convinced. Thoughts

[PSES] Country specific product regulations

Fellow Product safety professionals, I have a product with harmonized tariff code 8504.50.4000http://hts.usitc.gov/Table%2085.xml#8504.50.4000, I need to find out what regulations [EMC/product safety/restricted material/testing/product registration/etc.] that may apply to this product for

Re: [PSES] DC Boat Motor

I am not testing the boat just the motor. Other things is defined by combustion engines only that can be used in residential areas not DC electrical motors. -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Friday, December 13, 2013 1:30 PM To:

Re: [PSES] Cooling fan safety query

Hello Ian: The first question is whether or not the fan is necessary to meet the temperature requirements of the standard. If yes, then the fan and its alternates must be tested to prove that the end-product meets the temperature requirements. A UL-certified fan should reduce the testing

Re: [PSES] DC Boat Motor

In message 119fa9545c6e264b830c4582886d11908871b...@quimby.dw.local, dated Fri, 13 Dec 2013, Mark Schmidt mark.schm...@dornerworks.com writes: I am not testing the boat just the motor. Other things is defined by combustion engines only that can be used in residential areas not DC electrical

Re: [PSES] Country specific product regulations

1. My employer also makes 'ganged' chargers, and this is not the HTC that my customer used. See if the ITC can advise on your HT code. 2. Japan, Korea, and Taiwan have their national versions of 60950 and CISPR. 3. Talk to the International Approvals office of your friendly neighborhood one-stop