Maker Pro
Maker Pro

Need help Converting a variable Speed 12v drill to corded drill - 3rd wire?

Clayt

May 8, 2018
3
Joined
May 8, 2018
Messages
3
I need to convert this 12V Ridgid cordless drill to a corded 12v DC drill to use off my boat's battery supply.

I do not have the original drill battery, only the drill.

After dissembling the drill, there are 3 wires going to the switch from the battery. a RED, BLACK, AND WHITE. There are only 2 wires (red, black) leading from the switch to the motor.

I put 12V directly to the motor to verify the motor operates...it does.

However, when I hook 12V to the red & black wires that lead into the switch, the motor does NOT operate.

I have also tried to hook the white wire to both the + and - side of the circuit with no success.

Can anyone help me with this? What does the white wire do? I cannot find any info online.

The final result will need to be variable speed so direct-wiring the motor is not an option.

See attached pics.


Thanks in advance!
 

Attachments

  • IMG_6969.JPG
    IMG_6969.JPG
    58.8 KB · Views: 86
  • IMG_6968.JPG
    IMG_6968.JPG
    51 KB · Views: 79
  • IMG_6970.JPG
    IMG_6970.JPG
    47 KB · Views: 81
  • IMG_6971.JPG
    IMG_6971.JPG
    47.5 KB · Views: 78

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
Messages
6,514
I don't think the 'switch' you refer to is a switch - it's a variable speed controller that may well be dud hence it not working as you expect.
 

Clayt

May 8, 2018
3
Joined
May 8, 2018
Messages
3
Yes, you are correct. It is not a "switch" but I am using that term to describe the "variable speed controller". I do not believe it is a dud as the whole unit is brand new.
 

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
Messages
6,514
as the whole unit is brand new.
in which case you have the rest of the machine so should know where the wire came from???

It could be current sensing, temperature sensing, voltage tap (from a separate part of the battery) or even something more 'sinister' like a device to stop you using the drill with anything other than the genuine battery......

I'd find an after-market 12V drill trigger and use that in its place.
 

Clayt

May 8, 2018
3
Joined
May 8, 2018
Messages
3
I dont have the rest of it. The 3 wires were soldered to a little plastic plate with 3 metal contact pads that all make contact with the battery when it is inserted.

I was afraid it might be some sort of temperature sensor of some sort!

Any ideas on how to get around this or "hot wire" it? This is a small project with a small budget....

Thanks
 

Bluejets

Oct 5, 2014
6,920
Joined
Oct 5, 2014
Messages
6,920
Two wire variable speed switches are available from Ebay for around $5.00.
I used one to replace a dud switch in an old 7.2v makita as the original replacement speed switch was over $70.00.
Working great for last 12 months.
 

12vdc

Apr 13, 2011
46
Joined
Apr 13, 2011
Messages
46
I am the master of disaster when it comes to corded cordless tools.
I have converted many to muscle build versions by adding UPS 12 v 7ah SLA batteries.

as stated some drills had a 2 speed motor by using a center tap of the battery. (craftsman 7.2v drill)
I was learning and accidentally reversed polarity on the variable speed switch and got smoke. upon use of proper polarity it was dead.

can you disassemble the switch?
 

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
Messages
6,514
I have also tried to hook the white wire to both the + and - side of the circuit with no success.
Not sure why the controller didn't work in the first place but ^this^ could have caused permanent damage anyway....
 
Top