Flap up limit stop switch - Page 2

N788RV · #11 11-21-2006, 08:57 AM

Larry or Vlittle, I'm planning on mounting my flap switches the same way. Have either of you had problems with it. It looks simple to install I was just worried about the arm moving about the adel clamp over time.
http://bowenaero.com/mt3/archives/2...limit_swit.html

vlittle · #12 11-21-2006, 09:11 AM

I mounted my limit switch on a shop-made bracket screwed to the F902 (RV-9A) bulkhead. Since the limit switch has a long tab actuator, final adjustments were made by bending this tab.

Sorry, no pictures. My camera has gone walkabout.

Vern Little

decathlon737 · #13 09-01-2007, 09:55 PM

I'm about to install a micro stop switch in the flap system to stop motor from running in case I forget to turn it off on my Infinity grip. My question is, once the switch trips and opens the circuit, how do I restart the motor downward with the circuit open? Seems one would need both circuits closed before the motor would operate again. Probably is simple but I'm drawing a blank on this one. Thanks in advance.
Bill Woods
RV8 QB
IO 360 A1B

Stephen Lindberg · #14 09-01-2007, 10:48 PM

Offhand, I suggest wiring a DPST relay into the flap circuit. One set of contacts controls power to the motor. The other set of contacts is wired in series with the relay coil. The relay is held closed while the flap motor is running by wiring the relay coil (in series with a set of relay contacts) in parallel with the flap motor. The end of run switches (either the up or down switch, wire them in series and use one relay) open the relay coil circuit which opens the relay and cuts power to the motor. One set of contacts on the flap switch bypasses the limit switches so the motor can start with a limit switch open. This would require a three pole switch somewhere, I think. That is where I would start. I haven't drawn out the circuit or chased down parts at Mouser, these are just general musings off the top of my head but I think this principle (called a latching relay) could work. I think there are relays made especially for this purpose. I chose not to do this on my project because it adds weight, takes up space, cost money, adds complexity, and adds more points of failure with two modes of failure (flap motor doesn't run or flap motor runs away). Each to his own. Hope this circuit makes sense to you. It barely makes sense to me when I read it, but I have done this type of circuit before and it can be made to work.

az_gila · #15 09-01-2007, 10:57 PM

Quote:

Originally Posted by decathlon737

I'm about to install a micro stop switch in the flap system to stop motor from running in case I forget to turn it off on my Infinity grip. My question is, once the switch trips and opens the circuit, how do I restart the motor downward with the circuit open? Seems one would need both circuits closed before the motor would operate again. Probably is simple but I'm drawing a blank on this one. Thanks in advance.
Bill Woods
RV8 QB
IO 360 A1B

Toys to the rescue again....

How many guys remember Meccano building toys?
Made in Liverpool till they went bust.... and sold out to the French...

This schematic for a reversing motor for toys is essentially the same as our flap circuits, but with up/down limit switches instead of an over-run clutch.

http://internationalmeccanomen.org.u...control2b2.htm

The limit switches are NC, and open when the travel range is reached.

gil in Tucson - liked my Meccano when I was a kid... teaches you a lot about small nuts and bolts....

Stephen Lindberg · #16 09-01-2007, 11:28 PM

Gil: I was a Gilbert Erector Set boy, myself. I think it was similar to Meccano.

Your circuit is simpler and better than the one I dreamed up.

az_gila · #17 09-02-2007, 01:17 AM

Quote:

Originally Posted by Stephen Lindberg

Gil: I was a Gilbert Erector Set boy, myself. I think it was similar to Meccano.

Your circuit is simpler and better than the one I dreamed up.

Yes... the Erector set was a US copy of the original Meccano set.

I was in the UK at that time, and the Meccano factory was near central Liverpool, and visiting it was a school outing.
It was also home to Hornby O and OO trains and Dinky toy cars (predecessor to Matchbox cars, just a little bigger). A great place for a school visit...

http://www.dalefield.com/mwes/history/index.html

gil in Tucson

pierre smith · #18 09-02-2007, 06:24 AM

Quote:

Originally Posted by az_gila

Toys to the rescue again....

How many guys remember Meccano building toys?
Made in Liverpool till they went bust.... and sold out to the French...

This schematic for a reversing motor for toys is essentially the same as our flap circuits, but with up/down limit switches instead of an over-run clutch.

http://internationalmeccanomen.org.u...control2b2.htm

The limit switches are NC, and open when the travel range is reached.

gil in Tucson - liked my Meccano when I was a kid... teaches you a lot about small nuts and bolts....

Hi Bill,
My Air Tractor has two limit switches for up and down stops. I just replaced one because the flaps wouldn't come up. Buy a good one with this part number: BZ-2R5551-A2 from any Air Tractor dealer or maybe Spruce. Don't go Radio Shack.

Regards,
Pierre

decathlon737 · #19 09-02-2007, 07:42 AM

Thanks guys, I get it now.
Bill Woods
RV8 QB

az_gila · #20 09-02-2007, 09:51 AM

This is a copy from another posting of mine. As stated above, you need good switches, especially since the limit switch sees the load current of the motor. A 5 Amp DC rated switch should be OK for us...

------------------

You might be better of using true Microswitches (made by Honeywell) for this application, similar to the gear switches in certified planes.

This is an unsealed version, but should be OK if it's under the canopy away from any possible water entry. Sealed versions are available. Each switch has both NC and NO contacts.

They are not very expensive, and can be bought at Mouser...

http://www.mouser.com/catalog/631/1346.pdf

This Allied Electronics page give the DC contact rating, at 5 Amps it should be able to drive your lamps.

http://www.alliedelec.com/catalog/pf.asp?FN=969.pdf

------------

UPDATE

The Cherry switch part number given in the thread link of the previous post does not seem to have a DC current rating.

Some of the Microswitch parts do, and some are AC only. This Honeywell chart will let you check distributor part numbers for the current rating...

http://sensing.honeywell.com/index.c...c&docId=111781

The AC rated switches may work fine, but if you are buying a new switch, why not buy a correctly rated one since it does switch the fairly high motor current?

hope this helps... gil A