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Relay Bounce
As one who's never used a relay before in anything critical I come up
with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
Relay Bounce
On 05/17/2011 12:53 PM, Jim Thompson wrote:
As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? Only if your circuit depends on them not bouncing. I don't know for sure. But I would not only not be surprised if it happened, I would not be surprised if it _didn't_ happen with one brand of relay, and _did_ with another -- so even if you have a dozen on your bench that don't bounce, I wouldn't count on all relays not bouncing. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html |
Relay Bounce
On Tue, 17 May 2011 12:53:00 -0700, Jim Thompson wrote:
As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson They can do. It depends on the relay construction and whether you are talking about normally open or normally closed contacts. Solve the bounce on closing though, and you may have fixed both instances! Quite often mechanical switches are worse than relays. -- Mick (Working in a M$-free zone!) Web: http://www.nascom.info Filtering everything posted from googlegroups to kill spam. |
Relay Bounce
On Tue, 17 May 2011 12:53:00 -0700, Jim Thompson
wrote: As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson --- Yes. -- JF |
Relay Bounce
On Tue, 17 May 2011 16:11:20 -0500, John Fields
wrote: On Tue, 17 May 2011 12:53:00 -0700, Jim Thompson wrote: As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson --- Yes. That's just as well... easier to model ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Romneycare is nothing like Obamacare Except for those parts which are the same ;-) |
Relay Bounce
On Tue, 17 May 2011 14:27:55 -0700, Jim Thompson
wrote: On Tue, 17 May 2011 16:11:20 -0500, John Fields wrote: On Tue, 17 May 2011 12:53:00 -0700, Jim Thompson wrote: As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson --- Yes. That's just as well... easier to model ;-) ...Jim Thompson --- Indeed, and intrinsically safer, since assuming that there will be bounce on break forces the designer to account and compensate for it whether it's there or not. Win-win, yes? -- JF |
Relay Bounce
On Tue, 17 May 2011 17:24:31 -0500, John Fields
wrote: On Tue, 17 May 2011 14:27:55 -0700, Jim Thompson wrote: On Tue, 17 May 2011 16:11:20 -0500, John Fields wrote: On Tue, 17 May 2011 12:53:00 -0700, Jim Thompson wrote: As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson --- Yes. That's just as well... easier to model ;-) ...Jim Thompson --- Indeed, and intrinsically safer, since assuming that there will be bounce on break forces the designer to account and compensate for it whether it's there or not. Win-win, yes? You bet! I'm of the Greek School... why use a 2" x 4" when you have a 2" x 6" ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Romneycare is nothing like Obamacare Except for those parts which are the same ;-) |
Relay Bounce
Jim Thompson wrote: On Tue, 17 May 2011 17:24:31 -0500, John Fields wrote: On Tue, 17 May 2011 14:27:55 -0700, Jim Thompson wrote: On Tue, 17 May 2011 16:11:20 -0500, John Fields wrote: On Tue, 17 May 2011 12:53:00 -0700, Jim Thompson wrote: As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson --- Yes. That's just as well... easier to model ;-) ...Jim Thompson --- Indeed, and intrinsically safer, since assuming that there will be bounce on break forces the designer to account and compensate for it whether it's there or not. Win-win, yes? You bet! I'm of the Greek School... why use a 2" x 4" when you have a 2" x 6" ;-) Real men use at least a 2"x12", and prefer pressure treated. :) -- It's easy to think outside the box, when you have a cutting torch. |
Relay Bounce
On Tue, 17 May 2011 19:20:40 -0400, "Michael A. Terrell"
wrote: Jim Thompson wrote: On Tue, 17 May 2011 17:24:31 -0500, John Fields wrote: On Tue, 17 May 2011 14:27:55 -0700, Jim Thompson wrote: On Tue, 17 May 2011 16:11:20 -0500, John Fields wrote: On Tue, 17 May 2011 12:53:00 -0700, Jim Thompson wrote: As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson --- Yes. That's just as well... easier to model ;-) ...Jim Thompson --- Indeed, and intrinsically safer, since assuming that there will be bounce on break forces the designer to account and compensate for it whether it's there or not. Win-win, yes? You bet! I'm of the Greek School... why use a 2" x 4" when you have a 2" x 6" ;-) Real men use at least a 2"x12", and prefer pressure treated. :) --- Nonsense. Real men use what's appropriate. -- JF |
Relay Bounce
Jim Thompson wrote:
As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson Yes, but nothing at all like the magnitude and duration of the bounce on closing. In general, you worry more about arcing on break and bouncing on make. For example, if you put an RC snubber across the contacts to minimize arcing, the current that was flowing through them keeps flowing when the contacts open - through the snubber. Thus the rest of the circuit is "unaware" that the contacts have opened, and will also be unaware if the contacts re-close on a bounce. The contacts "appear" to be closed during that bounce. Ed |
Relay Bounce
Jim Thompson wrote:
As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson All relays i know of are made in such a way that guarantees there is no bounce on opening. They were not designed to not bounce; it is the design that prevents bouncing on opening. |
Relay Bounce
John Fields wrote: On Tue, 17 May 2011 19:20:40 -0400, "Michael A. Terrell" wrote: Jim Thompson wrote: On Tue, 17 May 2011 17:24:31 -0500, John Fields wrote: On Tue, 17 May 2011 14:27:55 -0700, Jim Thompson wrote: On Tue, 17 May 2011 16:11:20 -0500, John Fields wrote: On Tue, 17 May 2011 12:53:00 -0700, Jim Thompson wrote: As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson --- Yes. That's just as well... easier to model ;-) ...Jim Thompson --- Indeed, and intrinsically safer, since assuming that there will be bounce on break forces the designer to account and compensate for it whether it's there or not. Win-win, yes? You bet! I'm of the Greek School... why use a 2" x 4" when you have a 2" x 6" ;-) Real men use at least a 2"x12", and prefer pressure treated. :) --- Nonsense. Real men use what's appropriate. Well, if you can no longer swing a 2"x12", use whatever you can still lift. ;-) -- It's easy to think outside the box, when you have a cutting torch. |
Relay Bounce
"Michael A. Terrell" wrote in message
m... Real men use at least a 2"x12", and prefer pressure treated. :) ....and then burn the scraps (I love the smell of copper arsenate in the morning - NOT) |
Relay Bounce
"Robert Baer" wrote in message
net... All relays i know of are made in such a way that guarantees there is no bounce on opening. They were not designed to not bounce; it is the design that prevents bouncing on opening. Are Mercury wetted contacts still used? That was one way to keep low energy (non - arcing) contacts from bouncing. |
Relay Bounce
Oppie wrote: "Michael A. Terrell" wrote in message m... Real men use at least a 2"x12", and prefer pressure treated. :) ...and then burn the scraps (I love the smell of copper arsenate in the morning - NOT) What scraps? -- It's easy to think outside the box, when you have a cutting torch. |
Relay Bounce
Jim Thompson wrote:
You bet! I'm of the Greek School... why use a 2" x 4" when you have a 2" x 6" ;-) Then you should use a 2" x 3.236" -- Reply in group, but if emailing add one more zero, and remove the last word. |
Relay Bounce
"Jim Thompson" wrote in message ... As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. Relays bounce when you close a contact. If you have a situation where this will cause a problem, put a capacitor across the contacts or buy a mercury wetted relay for really sensitive situations. Shaun |
Relay Bounce
Shaun wrote:
"Jim Thompson" wrote in message ... As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson James E.Thompson, CTO | mens | Analog Innovations, Inc. | et | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | Phoenix, Arizona 85048 Skype: Contacts Only | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. Relays bounce when you close a contact. If you have a situation where this will cause a problem, put a capacitor across the contacts or buy a mercury wetted relay for really sensitive situations. Shaun I don't think they bounce when opening, but for sure, the arc is there, especially with reactive loads. -- David dgminala at mediacombb dot net |
Relay Bounce
On Sat, 28 May 2011 13:12:03 -0500, "Dave M" wrote:
Shaun wrote: "Jim Thompson" wrote in message ... As one who's never used a relay before in anything critical I come up with a dumb question... Do relays "bounce" when they are OPENING enough to re-contact? ...Jim Thompson James E.Thompson, CTO | mens | Analog Innovations, Inc. | et | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | Phoenix, Arizona 85048 Skype: Contacts Only | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. Relays bounce when you close a contact. If you have a situation where this will cause a problem, put a capacitor across the contacts or buy a mercury wetted relay for really sensitive situations. Shaun I don't think they bounce when opening, but for sure, the arc is there, especially with reactive loads. Some things are better measured? Because if there's an arc, there's something more than a simple dry contact opening going on. Grant. |
Relay Bounce
Grant wrote: On Sat, 28 May 2011 13:12:03 -0500, "Dave M" ? wrote: ?Shaun wrote: ?? "Jim Thompson" wrote in message ?? ... ?? ?? As one who's never used a relay before in anything critical I come up ?? with a dumb question... ?? ?? Do relays "bounce" when they are OPENING enough to re-contact? ?? ?? ...Jim Thompson ??? James E.Thompson, CTO | mens | ??? Analog Innovations, Inc. | et | ??? Analog/Mixed-Signal ASIC's and Discrete Systems | manus | ??? Phoenix, Arizona 85048 Skype: Contacts Only | | ??? Voice:(480)460-2350 Fax: Available upon request | Brass Rat | ??? E-mail Icon at http://www.analog-innovations.com | 1962 | ?? ?? I love to cook with wine. Sometimes I even put it in the food. ?? ?? Relays bounce when you close a contact. If you have a situation ?? where this will cause a problem, put a capacitor across the contacts ?? or buy a mercury wetted relay for really sensitive situations. ?? ?? Shaun ? ? I don't think they bounce when opening, but for sure, the arc is there, ?especially with reactive loads. Some things are better measured? Because if there's an arc, there's something more than a simple dry contact opening going on. Yeah. Current flow. -- It's easy to think outside the box, when you have a cutting torch. |
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