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kenryan
Joined: 20 Oct 2009 Posts: 424
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Posted: Wed May 23, 2018 9:46 am Post subject: Testing crowbar |
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For initial and periodic testing of the crowbar ov module would it be acceptable to connect two little 9v batteries in series as the power source?
Sent from my Android. Sorry Steve.
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user9253
Joined: 28 Mar 2008 Posts: 1908 Location: Riley TWP Michigan
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Posted: Wed May 23, 2018 10:11 am Post subject: Re: Testing crowbar |
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How about this circuit. Picture attached.
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kenryan
Joined: 20 Oct 2009 Posts: 424
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Posted: Wed May 23, 2018 11:30 am Post subject: Testing crowbar |
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Joe, I should have mentioned that I am still in "kindergarten" regarding electronics. I am just not following your diagram. It looks to me like it shows disconnecting the ground wire from the ov module and connecting it to the negative terminal of a 3-6 volt battery, and then connecting the positive terminal to ground? Somehow I think I cannot be reading it correctly, and even if I am, I am baffled as to how this would test the 16 volt set point for the ov module. Ken
On Wed, May 23, 2018 at 10:11 AM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
How about this circuit. Picture attached.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=480351#480351
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http://forums.matronics.com//files/ov_test_142.jpg
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nuckolls.bob(at)aeroelect Guest
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Posted: Wed May 23, 2018 11:40 am Post subject: Testing crowbar |
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At 12:45 PM 5/23/2018, you wrote:
Quote: | For initial and periodic testing of the crowbar ov module would it be acceptable to connect two little 9v batteries in series as the power source? |
YES
Bob . . .
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user9253
Joined: 28 Mar 2008 Posts: 1908 Location: Riley TWP Michigan
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Posted: Wed May 23, 2018 12:34 pm Post subject: Re: Testing crowbar |
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Ken,
You are reading the diagram correctly. When batteries are connected in series, they are connected negative to positive to negative to positive. When the over-voltage module is disconnected from ground, the loose wire will be positive. If you insert 3 flashlight batteries in series as shown, the voltages add up. 12 volts for the aircraft battery plus 4.5 volts for the flashlight batteries equals 16.5
If you want to trip a 5 amp circuit breaker, "D" cells should do it.
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kenryan
Joined: 20 Oct 2009 Posts: 424
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Posted: Wed May 23, 2018 1:15 pm Post subject: Testing crowbar |
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Thanks Joe. I understand now (mostly). I tried the two 9 volt batteries and that didn't work. I completely forgot about "current" needed to trip the breaker. Also, I guess I didn't really understand how the ov module works. I thought it was just a normally open micro switch that "magically" closes at 16 volts. I would have thought the ground wire of the ov module would be "dead" at less than 16 volts. But now I realize it must be more than that. It must be that current constantly flows through the ov module, but at 16 volts something else happens. I must have read an explanation in the "Connection" but obviously it didn't stick.
Also, I will be tripping a 7.5 amp breaker. The buss will be powered by a 17 amp power supply (max setting is 13.9v). Do you think the three D cells will trip the larger breaker?
Ken
On Wed, May 23, 2018 at 12:34 PM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Ken,
You are reading the diagram correctly. When batteries are connected in series, they are connected negative to positive to negative to positive. When the over-voltage module is disconnected from ground, the loose wire will be positive. If you insert 3 flashlight batteries in series as shown, the voltages add up. 12 volts for the aircraft battery plus 4.5 volts for the flashlight batteries equals 16.5
If you want to trip a 5 amp circuit breaker, "D" cells should do it.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=480356#480356
====================================
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Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
====================================
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
====================================
WIKI -
errer" target="_blank">http://wiki.matronics.com
====================================
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
====================================
|
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ceengland7(at)gmail.com Guest
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Posted: Wed May 23, 2018 2:21 pm Post subject: Testing crowbar |
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Ken,
If you've got Bob's (B&C) OV module with red & black wires, it's effectively "God's own" zener diode, with voltage adjustment. Whenever voltage between red and black exceeds the set point (which you adjust with the little control), then the red & black wires are shorted together.
You can run the test with a 12V light bulb or 12V LED between the 12V battery and the red wire, and the lamp will light when the OV module fires. That would avoid needing enough power to trip a 7.5A breaker.
Charlie
On Wed, May 23, 2018 at 4:13 PM, Ken Ryan <keninalaska(at)gmail.com (keninalaska(at)gmail.com)> wrote:
Quote: | Thanks Joe. I understand now (mostly). I tried the two 9 volt batteries and that didn't work. I completely forgot about "current" needed to trip the breaker. Also, I guess I didn't really understand how the ov module works. I thought it was just a normally open micro switch that "magically" closes at 16 volts. I would have thought the ground wire of the ov module would be "dead" at less than 16 volts. But now I realize it must be more than that. It must be that current constantly flows through the ov module, but at 16 volts something else happens. I must have read an explanation in the "Connection" but obviously it didn't stick.
Also, I will be tripping a 7.5 amp breaker. The buss will be powered by a 17 amp power supply (max setting is 13.9v). Do you think the three D cells will trip the larger breaker?
Ken
On Wed, May 23, 2018 at 12:34 PM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Ken,
You are reading the diagram correctly. When batteries are connected in series, they are connected negative to positive to negative to positive. When the over-voltage module is disconnected from ground, the loose wire will be positive. If you insert 3 flashlight batteries in series as shown, the voltages add up. 12 volts for the aircraft battery plus 4.5 volts for the flashlight batteries equals 16.5
If you want to trip a 5 amp circuit breaker, "D" cells should do it.
--------
Joe Gores |
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kenryan
Joined: 20 Oct 2009 Posts: 424
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Posted: Wed May 23, 2018 4:08 pm Post subject: Testing crowbar |
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I rigged up three D cells as Joe suggested and the OV protection system checked out okay. The breaker tripped as expected. Thanks everybody.
On Wed, May 23, 2018 at 2:19 PM, Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:
Quote: | Ken,
If you've got Bob's (B&C) OV module with red & black wires, it's effectively "God's own" zener diode, with voltage adjustment. Whenever voltage between red and black exceeds the set point (which you adjust with the little control), then the red & black wires are shorted together.
You can run the test with a 12V light bulb or 12V LED between the 12V battery and the red wire, and the lamp will light when the OV module fires. That would avoid needing enough power to trip a 7.5A breaker.
Charlie
On Wed, May 23, 2018 at 4:13 PM, Ken Ryan <keninalaska(at)gmail.com (keninalaska(at)gmail.com)> wrote:
Quote: | Thanks Joe. I understand now (mostly). I tried the two 9 volt batteries and that didn't work. I completely forgot about "current" needed to trip the breaker. Also, I guess I didn't really understand how the ov module works. I thought it was just a normally open micro switch that "magically" closes at 16 volts. I would have thought the ground wire of the ov module would be "dead" at less than 16 volts. But now I realize it must be more than that. It must be that current constantly flows through the ov module, but at 16 volts something else happens. I must have read an explanation in the "Connection" but obviously it didn't stick.
Also, I will be tripping a 7.5 amp breaker. The buss will be powered by a 17 amp power supply (max setting is 13.9v). Do you think the three D cells will trip the larger breaker?
Ken
On Wed, May 23, 2018 at 12:34 PM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Ken,
You are reading the diagram correctly. When batteries are connected in series, they are connected negative to positive to negative to positive. When the over-voltage module is disconnected from ground, the loose wire will be positive. If you insert 3 flashlight batteries in series as shown, the voltages add up. 12 volts for the aircraft battery plus 4.5 volts for the flashlight batteries equals 16.5
If you want to trip a 5 amp circuit breaker, "D" cells should do it.
--------
Joe Gores |
|
|
| - The Matronics AeroElectric-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
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user9253
Joined: 28 Mar 2008 Posts: 1908 Location: Riley TWP Michigan
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Posted: Wed May 23, 2018 4:34 pm Post subject: Re: Testing crowbar |
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The over-voltage module normally conducts very little current. I do not know how much but perhaps microamps or a few milliamps. Unless there is a good reason for using a 7.5 amp breaker, I would replace it with a 5 amp so that it will trip sooner. I tested a homemade over-voltage circuit one time and the breaker smoked instead of tripping. Many power supplies will automatically shut down when short circuited.
I do not know the maximum current of a D cell. That 7.5 amp breaker will require more than 7.5 amps for a certain amount of time before it will trip. That is asking a lot out of a D cell.
If you only want to test the O.V. module and not the breaker, disconnect at least one of the O.V. module wires from the aircraft. Connect the O.V. module and your two 9 volt batteries and a 24 volt test light all in series. Make sure battery polarity is correct, positive to red.
Even if the O.V. module works at 18 volts, you will not know if it works at 16 volts.
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user9253
Joined: 28 Mar 2008 Posts: 1908 Location: Riley TWP Michigan
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