Timeline for Relay contact sticking while driving a capacitive load
Current License: CC BY-SA 3.0
18 events
| when toggle format | what | by | license | comment | |
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| Apr 13, 2017 at 12:32 | history | edited | CommunityBot |
replaced http://electronics.stackexchange.com/ with https://electronics.stackexchange.com/
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| Sep 8, 2016 at 6:34 | vote | accept | Whiskeyjack | ||
| Sep 7, 2016 at 11:19 | history | edited | SamGibson♦ | CC BY-SA 3.0 |
Changed ST BTB16 Triac datasheet link to the shorter one used on their website, to replace the original "bare" URL as I have noticed those URLs sometimes change on the ST website.
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| Sep 7, 2016 at 4:52 | comment | added | Whiskeyjack | @Sam - You are right. Thanks for pointing that out. I was thinking they will deliver 10A at 250VAC. | |
| Sep 6, 2016 at 23:56 | history | edited | SamGibson♦ | CC BY-SA 3.0 |
Added link to relay data on Panasonic website; updated resistive (i.e. max) relay contact rating to correct value (5A at 250VAC). Split long paragraph to improve readability.
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| Sep 6, 2016 at 23:50 | comment | added | SamGibson♦ | @Whiskeyjack - You said: "I am using a Panasonic relay (ALQ105) rated for 10 amps at 250V" - FYI, that's wrong. Those relays are rated (on the N.O. (Normally Open) side of the changeover contacts) for a resistive load of 5A at 250VAC (you might have been confused because they are rated for a resistive load of 10A at 125VAC). For confirmation, see the Panasonic data for those relays on their website here. So if you use those relays, you need to make the inrush current even lower than you originally expected! | |
| Sep 6, 2016 at 19:21 | answer | added | Vince Patron | timeline score: 2 | |
| Sep 6, 2016 at 18:44 | answer | added | soosai steven | timeline score: 0 | |
| Sep 6, 2016 at 17:27 | answer | added | F. Bloggs | timeline score: 1 | |
| Sep 6, 2016 at 17:01 | comment | added | Robert Endl | Power supplies can draw huge currents on power-up. I once tested a 15 W supply that triggered the protection circuit on a 200 W AC power supply. | |
| Sep 6, 2016 at 14:32 | answer | added | Dmitry Grigoryev | timeline score: 4 | |
| Sep 6, 2016 at 14:17 | comment | added | Bimpelrekkie | In some supplies such an NTC is used to limit the inrush current. What is also used is a series resistor (like you suggested) but which is shorted by a second relay a few moments after the main relay closes. | |
| Sep 6, 2016 at 14:16 | comment | added | Whiskeyjack | @spehro - Thanks for the suggestion. Lets see if I am able to find a drop in replacement for the current one. | |
| Sep 6, 2016 at 14:13 | comment | added | Whiskeyjack | @PlasmaHH - I was thinking of a solution which would bring the surge current within the working limits for sure. For ex - Using NTC with normal resistance of 20 ohms (just for example) should bring the surge down to 220/20 = 11 amps. After the surge is gone, the NTC resistance will reduce to some smaller value. Do you think my thought process is correct here? | |
| Sep 6, 2016 at 14:10 | comment | added | Spehro 'speff' Pefhany | As well as reducing the current with some kind of device, you might want to consider using a relay with contacts rated for 'tungsten load'- which are designed (metallurgically) to withstand a large surge without welding. | |
| Sep 6, 2016 at 14:06 | comment | added | PlasmaHH | If you are not sure about the surge current capabilities, then how can we be? | |
| Sep 6, 2016 at 14:06 | comment | added | dim | Maybe it would be worth it to first check with a scope the inrush current duration and peak value. Then you can choose the appropriate device that will be able to switch that, without having to overspecify things. | |
| Sep 6, 2016 at 14:02 | history | asked | Whiskeyjack | CC BY-SA 3.0 |