Rather than having to add on an airflow sensor of some ilk, there are two
other options that might be easier:
1. Use fans that have a fail indication lead. Most fans, especially the PC
variety, have a third wire that is used as a tachometer. Most give two
squarewave pulses per rotation. If your SCADA system can deal with that,
great. If not, a simple RC circuit used as an integrator, perhaps in
conjunction with a comparator, would be simple enough to build. Aside from
the tachometer types, there are other fans with locked-rotor indicators
instead of the tach, and others that have a low-speed warning indicator. If
you do a few searches, you can probably find a fan with the appropriate
status output(s) to do whatever you want.
2. Rather than relying on detection of the fan rotation/airflow, why not
use a thermostat instead (Klixon variety). That way you know if your PA is
actually in the danger zone due to either a fan failure or site HVAC failure
or other condition that causes the temperature to go above the limit.
--- Jeff
> -----Original Message-----
> From: [email protected]
> [mailto:[EMAIL PROTECTED] On Behalf Of Adam C. Feuer
> Sent: Monday, July 23, 2007 11:21 AM
> To: [email protected]
> Subject: [Repeater-Builder] Recommendation - Vane Switch
>
> Hello All,
>
> I'm looking for information from anyone who has experience and could
> recommend a good vane switch to be installed on several repeaters.
> Some of my machines are 2 1/2 hours from my house so visiting them
> often just doesn't happen.
>
> I would like to install a vane switch to monitor the PA Fan and
> connect the output of the switch into the sites SCADA system.
>
> Manufacturer, model #, price, and opinion would be greatly
> appreciated.
>
> Thanks!
>
> Adam N2ACF
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
> No virus found in this incoming message.
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> Version: 7.5.476 / Virus Database: 269.10.14/912 - Release
> Date: 7/22/2007 7:02 PM
>
>
