Film-Tech Forum ARCHIVE: Air-Sensing switch suitable for blower failure notification

This is topic Air-Sensing switch suitable for blower failure notification in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=007713

Posted by Brad Allen (Member # 470) on 12-26-2005, 03:36 PM:

I'd like comments about using this Grainger Air Switch to alert us to the fact that a lamphouse blower fails or didn't start.
I would insert the sensor into the pipe just above the lamphouse. Which would place it between the blower and the lamphouse.
Comments, good, bad, ugly?

I feel that maybe this is a better solution than putting a sail switch in the stack.

Posted by Mark Gulbrandsen (Member # 72) on 12-26-2005, 04:44 PM:

That is not unlike the air pressure switch thats used in the older Christie 3/4kw lamphouses. It appears that its made to work with a positive air pressure though so inserting it in the output side of an exhaust blower would be a must.

I feel that sail switches are also pretty reliable though and its pretty easy to install one in just about any lamphouse stack and wire it back in series with the safety circuit. Christie makes a sail switch update kit for their lamphouses that includes the switch, sail, bracket and hardware. It is also pretty inexpensive and very universal.

Mark

Posted by Monte L Fullmer (Member # 2797) on 12-27-2005, 12:29 AM:

I've seen some places that the exhaust fan switch closed a relay - both to the fan and to the 110v to the rectifier contactor circuit.

No fan on, no ignition.

Wish that STRONG would have installed some better sailfin switches that goes over the blowhole that shoots the air on the cathode pin for those older X-90 consoles.

Then, they got smart with the enclosed plenum for the cathode, but the muffin fan thingey for the anode pin is something else on the later X-90 consoles.

-Monte

[ 12-27-2005, 05:40 AM: Message edited by: Monte L Fullmer ]

Posted by Mark Gulbrandsen (Member # 72) on 12-27-2005, 07:54 AM:

quote: Monte L Fullmer
Wish that STRONG would have installed some better sailfin switches that goes over the blowhole that shoots the air on the cathode pin for those older X-90 consoles.

Then, they got smart with the enclosed plenum for the cathode, but the muffin fan thingey for the anode pin is something else on the later X-90 consoles.

They all work just fine if kept clean. All lamphouse blowers should be removed and the squirel cages, pipes, elbows, etc. cleaned and lubed (if needed) once a year. Blowers will last just about forever if you do this. Some blower motors need to be turned so their oil cups are facing up..... most new blowers don't have them at all.....Christie has switched to a giant all ball bearing motor in its latest console incarnation [thumbsup]

.

Mark

Posted by Monte L Fullmer (Member # 2797) on 12-27-2005, 01:19 PM:

Yep, did all of that and check those inlets once a month when I visit these 32, X-90's.

Boy, got that right about Christie consoles: loved that motor that sits over the plenum and even the older sleeved ones.

Like a windstorm inside of those units-especially the Reference consoles with the two blowers.

Posted by Steve Scott (Member # 630) on 12-28-2005, 01:27 PM:

We used the original switches in question at Lakeville, and they were wired to general alarm buzzers in the ceiling near their respective groups of machines. They will certainly make management get around to fixing blower motors when the alarms go off continuously.