Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: bulkhead on December 18, 2007, 10:35:17 PM

Title: motor has 4 wires...what are they? (new development)
Post by: bulkhead on December 18, 2007, 10:35:17 PM
I have a wheelchair motor that has a plug with 4 wires: 2 black, 1 red, 1 blue. The resistance between the 2 black wires is 60 ohms for both the motors I have, and the resistance between the red and blue wires are 4.5 ohm, 30 ohm, for each motor.  The resistance between either the black wires and either red/blue was > 200 ohms.  The instruction manual says something about the two black wires being for braking.  Any ideas?
Title: Re: motor has 4 wires...what are they?
Post by: airman00 on December 18, 2007, 10:53:23 PM
Yep!

look on my blog for a project I did with wheelchair motors ( link is in my signature)

For robotics applications, you could just ignore the black wires , since the wheelchair is heavily geared. Once you dont give the wheelchair power , it will stop and it is really really hard to turn it then. 

What are you using the wheelchair motors for?




By the way here is a video of that project

[youtube=425,350]hsy11NAPgHc[/youtube]

Notice how it stops abruptly , I just stop giving it power and it does that. No braking whatsoever
Title: Re: motor has 4 wires...what are they?
Post by: bulkhead on December 18, 2007, 11:12:12 PM
Nice robot, having a kill switch is a good idea!

I'm going to use a pair of Victor 883's to control these motors, hopefully 60A continuous is enough.

Just for future reference, the motor whose terminal resistance measured 30ohms, I cleaned the motor brushes and its now within the 1-5ohm range like the manual said it should be.

Thanks for the help.
Title: Re: motor has 4 wires...what are they?
Post by: airman00 on December 19, 2007, 01:05:51 PM
I'm going to use a pair of Victor 883's to control these motors, hopefully 60A continuous is enough.


Yea, 60A continuous is more than enough, my motors draw 15 A continuous each.

Thanks for the help.
No problemo   ;D

Title: Re: motor has 4 wires...what are they? (resolved)
Post by: bulkhead on December 27, 2007, 11:25:19 PM
When I hooked up power the motors barely moved.  Then I came upon this http://books.google.com/books?id=fVqAZmluBAEC&pg=PA102&lpg=PA102&dq=electric+wheelchair+motor+brake+wires&source=web&ots=croBRvOltl&sig=dCjskTB_DXooSSFK3Nkf_d5CCKo

Apparently my motor did have a brake that is engaged unless power is applied to the 2 brake wires.  I took it off and now it coasts freely.  From watching the video it seems like your motors may have the same thing.
Title: Re: motor has 4 wires...what are they? (new development)
Post by: airman00 on December 30, 2007, 08:23:17 PM
THANKS!