Is a CDU constant

Basic electrical and electronics, such as DC/Analog control.
collectors
Posts: 64
Joined: Sun Oct 07, 2018 11:41 am

Is a CDU constant

Postby collectors » Sun Dec 26, 2021 4:51 pm

Hi, i am running a cable under my tracks for the point motors @ 20 volts DC via a CDU. i also have some wi-fi relay boards that work from 7-32v dc. Is it ok to run these relay boards off the same CDU supply. ??? Or has a CDU got some quirk that my relay boards may not like. Thanks

Bigmet
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Joined: Tue Aug 14, 2007 2:19 pm

Re: Is a CDU constant

Postby Bigmet » Sun Dec 26, 2021 5:16 pm

If you intend your wifi relay boards to be supplied by a CDU's output, then they will not work, the CDU only outputs a brief pulse of current on command. Worse yet the wifi relay boards may sustain damage, run them off a constant supply at the rated voltage.

collectors
Posts: 64
Joined: Sun Oct 07, 2018 11:41 am

Re: Is a CDU constant

Postby collectors » Sun Dec 26, 2021 5:54 pm

Bigmet wrote:If you intend your wifi relay boards to be supplied by a CDU's output, then they will not work, the CDU only outputs a brief pulse of current on command. Worse yet the wifi relay boards may sustain damage, run them off a constant supply at the rated voltage.

Many thanks, that saves a mistake. :oops:

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Bufferstop
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Re: Is a CDU constant

Postby Bufferstop » Sun Dec 26, 2021 11:58 pm

That was my initial reaction to what would happen if you attached something that's always on to a CDU, but the only time I've seen it done turned out totally different. The current drawn from the moment it was switched on was higher than the charging current to the capacitor, so it never charged up! Possible destruction might have happened if the load was disconnected then reconnected whilst the CDU was alive.
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