The Battery Contactor for Experimental AIrcraft

This short video presents important details regarding the selection and operation of a battery contactor, also known as a master contactor or master solenoid as used in an experimental homebuilt aircraft. A comparison is detailed regarding a comparison to the starter contactor or starter solenoid.

[@jeffrey9311]

Very clear -- thanks for taking the time to do this. You are a great instructor!

[@JeffreyinChina]

This UA-cam channel is favourite and quite important to my experimental aircraft educaiton

[@mikesax]

Always clear
Thanks for this one

[@austinbowman1433]

Keep the videos coming! Great work.

[@googacct]

Looking at the 4 post version of the contactor, it looks like there is a diode connected across smaller posts. I am guessing this is to eliminate arcing of the contacts of the master switch.

[@mmeyers111]

Please do a video on the starter relay.

[@superlight47]

@HomebuiltHELP, do they use this system in VLJ aircraft too or this are just designed and intend for piston aircraft? or is there a similar system design only for jet aircraft?

[@hamzalag2006]

Thank you

[@ajscain500]

You mentioned that in your “ next video “ you would talk about the reason for the diode . How to find that video please?

[@HomebuiltHELP]

Learn to use the UA-cam search and life will be much greater! Step 1 - click the circle icon picture next to HomebuiltHELP (that takes you to our channel homepage ) Step 2 - use the search box and enter "Diode" Easy!

[@ajscain500]

Thank you- sorry for being a dummy !😢

[@ajscain500]

Please bear with me . I truly am an electrical dummy : you say the wire
to the master switch / coil takes 1 amp. The electric source is the battery delivering 12V. Using Ohms Law I= V/R and so 1=12/R . Ie R must = 12. So where is the 12 ohm resistance coming from ?

[@HomebuiltHELP]

@@ajscain500 The coil itself has resistance. It uses power to create a magnetic field to engage the internal solenoid switch.

[@thales.tailan2668]

Hello, Does the maximum continuous current of the Master Contactors have to be the same as that of maximum continuous current of Starter Contactors ?

[@jjohnston94]

Is the switch you refer to installing at 5:31 the aircraft master switch?

[@HomebuiltHELP]

Yes! I should have mentioned that in the video. Thanks!

[@qeysqeys8736]

thank you