RE: Thermal breakers vs magnetic breakers for telecom
Ran into a similar problem with the thermals - they tripped during the 72 hour 55C operating limit test. Could have gone larger but it had more problems than fitting in the magnetic units. Gary -Original Message- From: John Juhasz [mailto:john.juh...@ge-interlogix.com] Sent: Wednesday, August 07, 2002 11:28 AM To: 'David Heald'; 'EMC_PSTC' Subject: RE: Thermal breakers vs magnetic breakers for telecom Yeah, I had used them . . . once. As they were a lower cost circuit breaker we spec'd them into a telecom system. What we didn't think about was the temperature extremes. For the higher temp tests for NEBS the higher temp breakers were too large and too expensive - for my management anyway. I suppose they could serve a purpose during the fire spread test - power disconnection of chassis. Just a couple of thoughts . . . John A. Juhasz GE Interlogix Fiber Options Div. Bohemia, NY -Original Message- From: David Heald [mailto:dhe...@tellium.com] Sent: Wednesday, August 07, 2002 11:18 AM To: 'EMC_PSTC' Subject: Thermal breakers vs magnetic breakers for telecom Greetings all, In the spirit of the continual quest for cost reduction, I have been asked to look into the use of thermal circuit breakers instead of magnetic ones. It seems like we rejected thermal breakers before for some reason, but now no one can remember why. Does anyone know of any telecom (or general) reasons why thermal circuit breakers may be unacceptable for telecom products? Thanks and Best Regards, Dave Heald --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
RE: Thermal breakers vs magnetic breakers for telecom
RE: Thermal breakers vs magnetic breakers8/7/02 David, One of the reasons they may have been rejected previously is their change in trip point due to temperature changes. The higher the ambient temperature gets the lower the trip point of the thermal device becomes. If they are used side by side in a PDU in a telecom rack they may even generate enough heat to trip with 80% or less of rated current flowing. The trip point of a hydraulic magnetic breaker does not change with temperature. Typically they have a must trip value at 125% of rated current and will hold 100% of rated current. The one thing about magnetic hydraulic breakers at an increased ambient temperature is that the amount of time required to trip at 125% of rated current will be less. In most cases this is not considered a bad attribute. I hope this helps John David Heald wrote: > >Greetings all, > In the spirit of the continual quest for cost reduction, I have been asked >to look into the use of thermal circuit breakers instead of magnetic ones. >It seems like we rejected thermal breakers before for some reason, but now >no one can remember why. > >Does anyone know of any telecom (or general) reasons why thermal circuit >breakers may be unacceptable for telecom products? > >Thanks and Best Regards, >Dave Heald > >--- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > >To cancel your subscription, send mail to: > majord...@ieee.org >with the single line: > unsubscribe emc-pstc > >For help, send mail to the list administrators: > Ron Pickard: emc-p...@hypercom.com > Dave Heald: davehe...@attbi.com > >For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > >All emc-pstc postings are archived and searchable on the web at: >http://ieeepstc.mindcruiser.com/ >Click on "browse" and then "emc-pstc mailing list" John Lach Manager Standards and Test john.l...@carlingtech.com Carling Technologies 60 Johnson Ave. Plainville, CT 06062 860-793-7167 www.carlingtech.com
RE: Thermal breakers vs magnetic breakers for telecom
When I worked on CATV power supplies I had two reasons for using magnetic; 1. Nuisance tripping of thermal breakers during high ambient temperatures 2. Magnetic breakers often carry a higher level of safety rating (UL Listed vs UL Recognized)than thermal and have higher short circuit maximum ratings. Darrell Locke Advanced Input Devices -Original Message- From: David Heald [mailto:dhe...@tellium.com] Sent: Wednesday, August 07, 2002 8:18 AM To: 'EMC_PSTC' Subject: Thermal breakers vs magnetic breakers for telecom Greetings all, In the spirit of the continual quest for cost reduction, I have been asked to look into the use of thermal circuit breakers instead of magnetic ones. It seems like we rejected thermal breakers before for some reason, but now no one can remember why. Does anyone know of any telecom (or general) reasons why thermal circuit breakers may be unacceptable for telecom products? Thanks and Best Regards, Dave Heald --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
RE: Thermal breakers vs magnetic breakers for telecom
Yeah, I had used them . . . once. As they were a lower cost circuit breaker we spec'd them into a telecom system. What we didn't think about was the temperature extremes. For the higher temp tests for NEBS the higher temp breakers were too large and too expensive - for my management anyway. I suppose they could serve a purpose during the fire spread test - power disconnection of chassis. Just a couple of thoughts . . . John A. Juhasz GE Interlogix Fiber Options Div. Bohemia, NY -Original Message- From: David Heald [mailto:dhe...@tellium.com] Sent: Wednesday, August 07, 2002 11:18 AM To: 'EMC_PSTC' Subject: Thermal breakers vs magnetic breakers for telecom Greetings all, In the spirit of the continual quest for cost reduction, I have been asked to look into the use of thermal circuit breakers instead of magnetic ones. It seems like we rejected thermal breakers before for some reason, but now no one can remember why. Does anyone know of any telecom (or general) reasons why thermal circuit breakers may be unacceptable for telecom products? Thanks and Best Regards, Dave Heald --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
Re: Thermal breakers vs magnetic breakers for telecom
Dave Heald wrote: >> Does anyone know of any telecom (or general) reasons why thermal circuit breakers may be unacceptable for telecom products? << Some thought on the matter suggests that thermal breakers may be too variable in their trip current and time over the usual temperature range of -40C to 65C. Cortland --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
