All DC motors are all unidirectional - its merely a case of reversing the
polarity wires - AC motors are wound so they need a rectifier to reverse the
field, so basically, by generic design, a DC motor actually can't be
designed as such to only go one way... the mechanicals coming off it of
course - now theres a different story... something abstract - for the US
citizens you may be familiar with the old Lionel toy trains - they were AC
wired and needed a seperate reverser coil to reverse the field polarity to
run backwards - the small modern stuff just reverses the polarity i.e
positive becomes negative and vice versa...
thanks
Muir (60 Crown)
>From: 72.lebaron@xxxxxxxxxxxxxx
>Reply-To: mailing-list@xxxxxxxxxxxxxxxx
>To: mailing-list@xxxxxxxxxxxxxxxx
>Subject: Re: IML: Reversing Moroso Window Motors
>Date: Wed, 15 May 2002 13:39:11 -0700
>
>
>> If these Moroso jobs are brush motors and are run off of D.C, as they
>>are
>>in this case, then the polarity can be reversed to make them run
>>backwards.
>>This is basically the function of the window motor switch and relay
>>anyhow.
>
>Pardon my ignorance about such matters.. I don't claim to be an automotive
>electrician by any stretch of the imagination. I recently replaced the
>window lift gears in my '72 Imp and noted, as in my '64 Merc and '76
>Eldorado that the window lift motors have two wires, one for up and one for
>down. The negative ground is accomplished by a ground strap at the base of
>the motor. When positive voltage is applied to one of the wires, the motor
>is activated. When positive voltage is applied to the other wire, the motor
>runs the opposite direction.
>
>Isn't it a bad thing when polarity is reversed on a DC motor that's not
>designed for such a function?
>
>DD <---Still trying to figure out something for my Merc!
>
>
>
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