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 11-25-2021, 10:41 PM   #21
Mister Moose
Senior Member
 
Mister Moose's Avatar
 
Join Date: Jun 2020
Location: Hartford area, CT
Posts: 374
Default Re: starter amps

Quote:
Originally Posted by Synchro909 View Post
Trouble is, a 12 v starter doesn't do the same job as a 6 v one. It spins the motor faster because it has more power, hence more than half the amps.
I don't follow this. Power and starter speed is not dependent on voltage, it's a function of design, the windings, and enough current at the battery to run it. Of course you could build a 6V starter to be more powerful.

The reason we build 12 volt systems, (and most modern aircraft at 24V, and tugboats at 32V) is to lower the current for the same power. Less resistive losses and as mentioned you can use smaller conductors. But it is not a power limitation.
Mister Moose is offline   Reply With Quote
Old 11-26-2021, 08:17 AM   #22
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 16,346
Default Re: starter amps

I always think of it as current draw. In other words, a load like a series wound electric starter motor will only draw the current it needs to function. The amount of current needed will vary depending on the torque it needs to turn and the condition of the motor. The voltage is just the electromotive force that the current uses to flow. A higher voltage will allow for less current being needed to do the same job even though the current changes same as the voltage so it's not quite proportional. The 6-volt starter will certainly turn faster if not modified to work with the higher voltage but it still won't have to draw as much amperage with twice the amount electromotive force and current available to it. It would have around 4X the power as on 6-volt.

Last edited by rotorwrench; 11-26-2021 at 09:29 AM.
rotorwrench is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 11-26-2021, 04:34 PM   #23
Synchro909
Senior Member
 
Synchro909's Avatar
 
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 7,444
Default Re: starter amps

Quote:
Originally Posted by rotorwrench View Post
I always think of it as current draw. In other words, a load like a series wound electric starter motor will only draw the current it needs to function. The amount of current needed will vary depending on the torque it needs to turn and the condition of the motor. The voltage is just the electromotive force that the current uses to flow. A higher voltage will allow for less current being needed to do the same job even though the current changes same as the voltage so it's not quite proportional. The 6-volt starter will certainly turn faster if not modified to work with the higher voltage but it still won't have to draw as much amperage with twice the amount electromotive force and current available to it. It would have around 4X the power as on 6-volt.
Give the man a prize!
__________________
I'm part of the only ever generation with an analogue childhood and a digital adulthood.
Synchro909 is offline   Reply With Quote
Old 11-27-2021, 12:14 PM   #24
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Largo Florida
Posts: 7,225
Default Re: starter amps

These threads always seem to take on a life of their own. The man asked a simple question and I think we chased him away.
Patrick L. is offline   Reply With Quote
Old 11-28-2021, 08:38 AM   #25
Bob Bidonde
Senior Member
 
Bob Bidonde's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 3,425
Default Re: starter amps

This starting motor data is from Dyke's Encyclopedia, and it applies to a starting motor in new condition:
Terminal Grounded (+)
Normal Armature Speed 1500 RPM
Amperage, Normal 175
Normal Running Torque 3 Lbs-Ft
__________________
Bob Bidonde
Bob Bidonde is offline   Reply With Quote
Old 11-28-2021, 03:44 PM   #26
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Largo Florida
Posts: 7,225
Default Re: starter amps

Sponsored Links (Register now to hide all advertisements)
Just get the little do-hickey Katy shows in post 15 and try it. Only takes a couple seconds. Its a great opportunity to buy another tool.
Patrick L. is offline   Reply With Quote
Reply

Thread Tools
Display Modes

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 12:51 AM.