Re: Disconnecting Relay sound like over-kill

Posted by Johno (A) on May 3, 2017 at 03:24:55

In Reply to: Delay Relays posted by Triode_Kingdom on May 2, 2017 at 21:14:51:

You said
"One potential issue with delay relays has to do with the relatively small contacts"

Correct that also includes SS time delay relays.

You said
"The delay relay will power a main relay, and that one will be wired so it latches electrically. In addition, one set of contacts will be wired to disconnect the delay relay. So, once the amplifier is fully operational, the delay relay will power down and cool off. Not only will its contacts only need to pass a few mA to activate the HV, its heater will only be used for a minute or so each time the amplifier is turned on"

The disconnection of the delay relay is simply overkill I've run a similar scenario using 24V/30A relay activated from SS delay mains relay / timer for 10 yrs without fault. You can safely derate the DC current rating by 50% into a inductive load ie transformer and still be well under the DC rating. Relay coil DCR for 12-24V are under 1k ohm so the current requirement are small. But install a diode - reverse biased across relay coil to absorb back EMF on turn on / off. Seriously this configuration has been used in cross bar / step by step electro-mechanical telco exchanges for generations....bullet proof.

Johno

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Follow Ups Full Thread

Topic - New Build- 1625 SE Triode Strapped - Misty - rcollege 12:33:42 05/02/17 (20)

Excellent work! - Triode_Kingdom 21:51:36 05/02/17 (5)

RE: Excellent work! - rcollege 22:50:56 05/02/17 (4)

Transmitter Caps - Triode_Kingdom 08:10:07 05/03/17 (3)

RE: Transmitter Caps - rcollege 09:52:07 05/03/17 (2)

RE: Transmitter Caps - Triode_Kingdom 13:06:12 05/03/17 (1)

Thank You! - rcollege 16:26:55 05/04/17 (0)

Nice job! nt - vinnie2 18:17:25 05/02/17 (0)

RE: New Build- 1625 SE Triode Strapped - Misty - Tre' 16:47:27 05/02/17 (1)

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RE: New Build- 1625 SE Triode Strapped - Misty - Michael Samra 13:53:32 05/02/17 (1)

RE: New Build- 1625 SE Triode Strapped - Misty - rcollege 17:10:55 05/02/17 (0)

RE: New Build- 1625 SE Triode Strapped - Misty - Mr_Steady 13:20:02 05/02/17 (7)

RE: Delay relay Tubes - gusser 13:44:27 05/02/17 (6)

Thank you gusser (NT) - Mr_Steady 16:30:43 05/02/17 (5)

RE: Thank you gusser (NT) - rcollege 17:16:44 05/02/17 (4)

Delay Relays - Triode_Kingdom 21:14:51 05/02/17 (3)

Re: Disconnecting Relay sound like over-kill - Johno 03:24:55 05/03/17 (2)

Re: Disconnecting Relay sound like over-kill - Tom Bavis 07:35:06 05/03/17 (1)

Re: Disconnecting Relay sound like over-kill - Triode_Kingdom 08:32:06 05/03/17 (0)

RE: New Build- 1625 SE Triode Strapped - Misty - rcollege 12:36:37 05/02/17 (0)

Follow Ups

Re: Disconnecting Relay sound like over-kill - Johno 03:24:55 05/03/17 (2)

Re: Disconnecting Relay sound like over-kill - Tom Bavis 07:35:06 05/03/17 (1)

Re: Disconnecting Relay sound like over-kill - Triode_Kingdom 08:32:06 05/03/17 (0)

Re: Disconnecting Relay sound like over-kill

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