Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 10-05-2024, 08:14 PM   #1
Tom Bellfoy
Senior Member
 
Tom Bellfoy's Avatar
 
Join Date: Oct 2010
Location: Cumberland, ON
Posts: 255
Default recommended current through 6 volt coil primary

Can anyone tell me what the recommended current (amps) should be running through a 6 volt ignition coil primary circuit in order to provide long life on ignition points on a model A ford. I can calculate the resistance just need the suggested amps
Tom Bellfoy is offline   Reply With Quote
Old 10-05-2024, 10:16 PM   #2
P.S.
Senior Member
 
Join Date: Jul 2012
Location: Hazzard County
Posts: 1,922
Default Re: recommended current through 6 volt coil primary

Should be around 3 amps
__________________
2024-2025 MAFCA Technical Director
P.S. is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 10-06-2024, 08:10 AM   #3
Badpuppy
Senior Member
 
Join Date: Dec 2017
Location: Guthrie, OK
Posts: 1,247
Default Re: recommended current through 6 volt coil primary

Long life is mostly provided by a properly functioning capacitor (condenser) to counter the inductance of the coil. Current/voltage varies with generator output @ rpm.
Badpuppy is offline   Reply With Quote
Old 10-06-2024, 10:11 AM   #4
Tom Bellfoy
Senior Member
 
Tom Bellfoy's Avatar
 
Join Date: Oct 2010
Location: Cumberland, ON
Posts: 255
Default Re: recommended current through 6 volt coil primary

ok I willgo with three amps
Thank you
Tom
Tom Bellfoy is offline   Reply With Quote
Old 10-06-2024, 10:33 AM   #5
katy
Senior Member
 
katy's Avatar
 
Join Date: Jun 2015
Location: Red Deer, Alberta
Posts: 5,716
Default Re: recommended current through 6 volt coil primary

Current should be measured w/the engine idling. Current when engine is not running will be a higher.
__________________
If you don't hear a rumor by 10 AM, start one!.
Got my education out behind the barn!
katy is offline   Reply With Quote
Old 10-06-2024, 11:08 AM   #6
P.S.
Senior Member
 
Join Date: Jul 2012
Location: Hazzard County
Posts: 1,922
Default Re: recommended current through 6 volt coil primary

Sponsored Links (Register now to hide all advertisements)
Quote:
Originally Posted by katy View Post
Current should be measured w/the engine idling. Current when engine is not running will be a higher.
The peak current won't be lower, the RMS (average) will be lower. In that case, it will depend on the cam lobe shapes (which changes dwell time). The simple answer to OP's question was in static amps with the circuit energized. So, I went that route.
__________________
2024-2025 MAFCA Technical Director
P.S. is offline   Reply With Quote
Old 10-07-2024, 08:09 AM   #7
Badpuppy
Senior Member
 
Join Date: Dec 2017
Location: Guthrie, OK
Posts: 1,247
Default Re: recommended current through 6 volt coil primary

Primary has dc resistance of 1.5 ohms, minimum battery of 6 volts gives 4 amperes, times dwell of 90%(?) is average 3.6 amps. But only if you believe the math.
Badpuppy is offline   Reply With Quote
Old 10-07-2024, 08:23 AM   #8
JoeCB
Senior Member
 
JoeCB's Avatar
 
Join Date: Nov 2018
Location: Farmington MI
Posts: 366
Default Re: recommended current through 6 volt coil primary

I was waiting for it .... eventually we would get to Mr. Ohm and E=!R (V=IR)
Joe B
JoeCB is offline   Reply With Quote
Old 10-07-2024, 08:29 AM   #9
old31
Senior Member
 
Join Date: Jan 2016
Posts: 2,461
Default Re: recommended current through 6 volt coil primary

Oh, my head hurts.
old31 is online now   Reply With Quote
Old 10-07-2024, 08:33 PM   #10
JoeCB
Senior Member
 
JoeCB's Avatar
 
Join Date: Nov 2018
Location: Farmington MI
Posts: 366
Default Re: recommended current through 6 volt coil primary

Quote:
Originally Posted by old31 View Post
Oh, my head hurts.
Oh, not that bad, could be worse, like E=MC˛
JoeCB is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 02:01 PM.