---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 12/25/22: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:35 PM - Master Relay current draw... (andymeyer) 2. 02:37 PM - Re: Master Relay current draw... (Charlie England) 3. 08:39 PM - Re: Master Relay current draw... (user9253) 4. 08:48 PM - Re: Master Relay current draw... (user9253) 5. 10:04 PM - Re: Master Relay current draw... (Robert L. Nuckolls, III) 6. 10:11 PM - Re: Master Relay current draw... (Bob Verwey) ________________________________ Message 1 _____________________________________ Time: 01:35:14 PM PST US Subject: AeroElectric-List: Master Relay current draw... From: "andymeyer" Old master relay in my Long EZ - it's pulling about 2.3 amps - just the relay itself - sounds like it's way high. Any recommendations for a low current replacement? What's the typical draw for one of these and what would cause the high draw? (I don't have the model of relay in front of me, but it appears to be a fairly standard relay) 12V system... Do these relays have a pull-in and a holding circuit, or are they just a single pull-in coil that is energized the entire time the relay is closed? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=509784#509784 ________________________________ Message 2 _____________________________________ Time: 02:37:56 PM PST US Subject: Re: AeroElectric-List: Master Relay current draw... From: Charlie England On 12/25/2022 3:34 PM, andymeyer wrote: > > Old master relay in my Long EZ - it's pulling about 2.3 amps - just the relay itself - sounds like it's way high. Any recommendations for a low current replacement? > > What's the typical draw for one of these and what would cause the high draw? (I don't have the model of relay in front of me, but it appears to be a fairly standard relay) 12V system... > > Do these relays have a pull-in and a holding circuit, or are they just a single pull-in coil that is energized the entire time the relay is closed? Might be a little high; you can download a datasheet from Spruce here: https://www.aircraftspruce.com/catalog/elpages/masterrelay.php Any chance the builder installed a starter relay in the master slot? Starter relays typically have higher coil current to engage quicker, etc. You can spend a bunch more money on a solid state model, but I wouldn't consider it good value. Charlie -- This email has been checked for viruses by Avast antivirus software. www.avast.com ________________________________ Message 3 _____________________________________ Time: 08:39:31 PM PST US Subject: AeroElectric-List: Re: Master Relay current draw... From: "user9253" According to this post: http://www.matronics.com/searching/getmsg_script.cgi?INDEX=117069337?KEYS=.6_amps_warm?LISTNAME=AeroElectric?HITNUMBER=3?SERIAL=18371020034?SHOWBUTTONS=YES A Cole-Hersee contactor draws 1 amp cold and drops to about 0.6 amps warm. Current is determined by the load, the contactor coil is this case. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=509791#509791 ________________________________ Message 4 _____________________________________ Time: 08:48:38 PM PST US Subject: AeroElectric-List: Re: Master Relay current draw... From: "user9253" Bob's Contactor duty cycle controller -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=509792#509792 Attachments: http://forums.matronics.com//files/contactor_duty_cycle_controller_171.pdf ________________________________ Message 5 _____________________________________ Time: 10:04:55 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Master Relay current draw... At 03:34 PM 12/25/2022, you wrote: > >Old master relay in my Long EZ - it's pulling about 2.3 amps - just >the relay itself - sounds like it's way high. Any recommendations >for a low current replacement? Yes, that IS waayyy too high for a battery contactor. It's been suggested that you may have inadvertently installed an intermittant duty contactor. Here's one option for a more appropriate device. https://tinyurl.com/y9nbkhgo See: http://aeroelectric.com/Pictures/Contactors/Battery_Contactor_Temps_1.jpg http://aeroelectric.com/Pictures/Contactors/Battery_Contactor_Temps_2.jpg Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 6 _____________________________________ Time: 10:11:49 PM PST US From: Bob Verwey Subject: Re: AeroElectric-List: Master Relay current draw... Andy the " homebuilt" master relay I purchased from Spruce recently does not even draw 1 amp. While working on the aircraft late one afternoon I forgot to turn it off...the next morning it was warm to the touch but the battery voltage was still in the normal range. On my old Bonanza I noticed that the starter contactor drew higher current than the master contactor, also they are the older style devices.. Best...Bob On 26 Dec 2022 00:39, "Charlie England" wrote: ceengland7@gmail.com> On 12/25/2022 3:34 PM, andymeyer wrote: > > > Old master relay in my Long EZ - it's pulling about 2.3 amps - just the relay itself - sounds like it's way high. Any recommendations for a low current replacement? > > What's the typical draw for one of these and what would cause the high draw? (I don't have the model of relay in front of me, but it appears to be a fairly standard relay) 12V system... > > Do these relays have a pull-in and a holding circuit, or are they just a single pull-in coil that is energized the entire time the relay is closed? Might be a little high; you can download a datasheet from Spruce here: https://www.aircraftspruce.com/catalog/elpages/masterrelay.php Any chance the builder installed a starter relay in the master slot? Starter relays typically have higher coil current to engage quicker, etc. You can spend a bunch more money on a solid state model, but I wouldn't consider it good value. Charlie -- This email has been checked for viruses by Avast antivirus software. www.avast.com ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.