Jump to content

positive ground to negative ground


frijolito

Recommended Posts

Hello everyone. I'm trying to convert over from positive ground to negative ground. Still keeping it 6 volts. I've read this great article from Fifth Avenue Garage and was wondering if its all I have to do. Any help with changing over or the steps it takes would be helpful. 

 https://fifthaveinternetgarage.blogspot.com/2017/06/changing-your-electrical-system-from.html

Edited by frijolito
Link to comment
Share on other sites

Turn the battery around so you can connect the ground cable to the negative post of the battery. Leave the other cable disconnected while you swap the wires on the ammeter. Once that is done connect the positive post of the battery to the other cable.

 

The article states it is not necessary to switch the wires on the ignition coil. You will get various opinions on this but the coil will function either way.

 

That's it.

  • Like 1
Link to comment
Share on other sites

I noticed the coil was wired backwards on my 51, fixed that but there was no noticeable difference.  Now on a different brand (VW) the spark was so weak it would not fire the engine, corrected that and it fired right up. 

  • Like 1
Link to comment
Share on other sites

The Radio may be polarity sensitive. put a fat (!) bridge rectifier if so.

I don´t know which type of e- motors are used:

E- motors can have the field and armature windings inline or have a permanent magnet (sorry, I don´t know the correct technical terminology).

The heater fan may run reverse, depends on the style.: Try if airstream comes right out

Wiper motors too, which would be irrelevant: but try if they reach the parking position.

 

  • Like 1
Link to comment
Share on other sites

1 hour ago, milo9rat said:

I kept my 6V wiper motor when i changed to 12V neg. and used one of these and wiper works great and parks...

61g7x7QxOaL._AC_SL1100_.jpg

your 6v wiper motor would have worked fine without that step-down transformer. It would just run twice as fast.

Link to comment
Share on other sites

This is what I bought.. It works great, wiper runs at original speed and the park works too.. At $20 bucks, can't go wrong in my opinion....

71kUr8vF51L._AC_SL1500_.jpg

Edited by milo9rat
Link to comment
Share on other sites

8 hours ago, frijolito said:

In 1939 my wiper motors are still vacuum. 

Yes that is correct for the 1939 Plymouth.   The 1939 Chrysler, Desoto and Dodge all came standard with the Autolite electrical wiper motor.

 

The lower line of Plymouth retained the trico vacuum wiper motor system.

 

Rich Hartung

desoto1939@aol.com

Link to comment
Share on other sites

1 hour ago, milo9rat said:

Sniper.. How can it beat the linkage up?? It doesn't run faster, runs at the same speed as it did on 6V....

Not Sniper but, according to your post, the wipers on running on the 6v output of the device (resistor pack) that is installed not 12v.  I ran a 6v motor on 12 once just to try it:  Fast!  and would surely put a strain on mechanical linkages.

Link to comment
Share on other sites

6 hours ago, milo9rat said:

Sniper.. How can it beat the linkage up?? It doesn't run faster, runs at the same speed as it did on 6V....

 

I think you are thinking of how your wiper runs after you put that DC to DC converter in.  Which means your 6v wiper motor is running on 6v as designed.

 

I said running a 6v wiper motor on 12v was a bad idea.,  BTDT.  I ended up building a current limiting circuit to slow it down.  Works good. 

 

A link to what I think you bought

 

https://www.ebay.com/itm/DC-12V-24V-to-6V-20A-120W-STEP-DOWN-DC-DC-Power-Converter-Regulator-/390805682663

  • Like 1
Link to comment
Share on other sites

Yes, 'transformer' is not the correct terminology, however, the DC is converted into an AC source (a square wave by switching the dc 'on and off') then converted to the appropriate voltage, up or down then converted back to DC in these dc - dc converters.

 

If the linkages are free and not binding, I can't see how the extra speed from a small DC motor would damage them.  I have never had any issues running a a 6v wiper motor on 12v, but my wipers have only been single wiper arms.

Link to comment
Share on other sites

Single arm wipers don't have linkages, so any experience with those is not relatable.

 

Whether you can see how it would happen or not is also not relatable, it happens from direct observation and experience.  As they say, theory is fine, till it meets reality.

  • Like 1
Link to comment
Share on other sites

And one failed attempt does not make one an expert.

 

Limiting the current does not slow it down,  voltage level controls the speed.

Link to comment
Share on other sites

Some one wiser than me said you can use the chassis as ground for both positive and negative systems.  If this is indeed the case, 12 volt neg accessories can be powered from a dedicated source like a battery in the trunk, with negative grounded to frame or body sheet metal. Then the accessories can be wired as one normally would from dedicated power through the switch and then either self grounded through the mount r wired to a body or frame bolt.

Link to comment
Share on other sites

On 7/11/2020 at 6:02 PM, maok said:

And one failed attempt does not make one an expert.

 

Limiting the current does not slow it down,  voltage level controls the speed.

 

How about this then, I finished my electronics training in 1984 and have 36+ years experience.  That qualify as an expert for you?

 

It is apparent to me you know little about Ohm's law, the basic foundation of electricity and electronics.

 

What determines Voltage? Current times resistance.  The wiper motor's resistance does not change so in order to change the voltage you have to change the current.  You limit the current, you limit the voltage, period. 

 

So go tell my wipers that limiting current does not work.

 

https://youtu.be/Ip-mtPqGBd4

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use