Nice 12vdc gearmotors available
Posted by
arcstarter
on 2002-02-08 11:00:56 UTC
List,
I recently located a few interesting types of gearmotors for sale at
the local junk store. They sell mail order.
I'm planning on using one or two of these for rough power feed
control. Bought some 1/2-10 ACME rod and nuts etc... Here's what I
found:
The first sort is a pair of car door window motors for $25/pr:
http://www.meci.com/default.asp?
cat_to_search=&searchall=&partno=&description=&topsearch=&mode=getitem
s&curpage=2
(motor part number 420-0538 or search www.meci.com for that number)
These contain a square steel output shaft. Case cover retained via
T-20 screws. Not bad power: 12vdc 3 amp 56rpm 50 in*lb torque.
Internally - the worm is steel but the wormgear is plastic. Frame is
not electrically connected to the motor. Two leads. Reversable (of
course). Aluminum case. Shaft only extends out one side, but you
should be able to bore through behind the wormgear for an extended
shaft arrangement. For my project I turned a steel bushing with
setscrew which slides over the motor's square output stub. Torque is
transmitted via the setscrew - seems to do the job well enough...
The second is a car windshield motor for $16:
http://www.meci.com/default.asp?mode=getitems&category=254
(look for motor number 420-0578 about 2-3 pages down)
This motor is heavier and has more shaft power than the above
windshield motors. Speed on 'high' is 106rpm or thereabouts. Frame
is 'hot' - ie- frame is the return path. (This might complicate your
mounting arrangement.) Two motor leads - one for fast, one for
slow. Output shaft appears to have some sort of interference spline
on it - with a steel crank arm pressed down into the spline with a
retaining nut behind it. Might be difficult to adapt. The motor I
have will run backwards if you power it backwards, but I've heard
rumors that some of the windshield wiper motors lack proper internal
thrust bearings for extended reverse running. "...You takes your
chances..."
I would think a windshield wiper motor would be rated for continuous
duty - as opposed to a window up/down motor - which might be only
intermittant duty etc.
Speed could be controlled in any number of ways. I'd probably go
with the tried and true 555 + big FET approach for an open loop PWM
controller... Or a variac + transformer + rectifier would also do it.
Sorry if anyone thinks this is 'spammy' - but I thought some folks
might be looking for this sort of thing. IMO the price is right on
both of these parts. Standard disclaimers.
-Bill (Sr. Staff Mad Scientist)
I recently located a few interesting types of gearmotors for sale at
the local junk store. They sell mail order.
I'm planning on using one or two of these for rough power feed
control. Bought some 1/2-10 ACME rod and nuts etc... Here's what I
found:
The first sort is a pair of car door window motors for $25/pr:
http://www.meci.com/default.asp?
cat_to_search=&searchall=&partno=&description=&topsearch=&mode=getitem
s&curpage=2
(motor part number 420-0538 or search www.meci.com for that number)
These contain a square steel output shaft. Case cover retained via
T-20 screws. Not bad power: 12vdc 3 amp 56rpm 50 in*lb torque.
Internally - the worm is steel but the wormgear is plastic. Frame is
not electrically connected to the motor. Two leads. Reversable (of
course). Aluminum case. Shaft only extends out one side, but you
should be able to bore through behind the wormgear for an extended
shaft arrangement. For my project I turned a steel bushing with
setscrew which slides over the motor's square output stub. Torque is
transmitted via the setscrew - seems to do the job well enough...
The second is a car windshield motor for $16:
http://www.meci.com/default.asp?mode=getitems&category=254
(look for motor number 420-0578 about 2-3 pages down)
This motor is heavier and has more shaft power than the above
windshield motors. Speed on 'high' is 106rpm or thereabouts. Frame
is 'hot' - ie- frame is the return path. (This might complicate your
mounting arrangement.) Two motor leads - one for fast, one for
slow. Output shaft appears to have some sort of interference spline
on it - with a steel crank arm pressed down into the spline with a
retaining nut behind it. Might be difficult to adapt. The motor I
have will run backwards if you power it backwards, but I've heard
rumors that some of the windshield wiper motors lack proper internal
thrust bearings for extended reverse running. "...You takes your
chances..."
I would think a windshield wiper motor would be rated for continuous
duty - as opposed to a window up/down motor - which might be only
intermittant duty etc.
Speed could be controlled in any number of ways. I'd probably go
with the tried and true 555 + big FET approach for an open loop PWM
controller... Or a variac + transformer + rectifier would also do it.
Sorry if anyone thinks this is 'spammy' - but I thought some folks
might be looking for this sort of thing. IMO the price is right on
both of these parts. Standard disclaimers.
-Bill (Sr. Staff Mad Scientist)