> Hello,
>
> we're currently using this gear motor in a servo-type application:
> http://www.casaferreira.com.br/pdf/CEP453042.pdf
>
> 12VDC, 57W, nominal 9Nm/75rpm/18A, stall 36Nm/50A, idle speed 100rpm, gear
> 63:1
>
> There are two problems I need to solve. One is that the stall torque is not
> enough. Ideally it would have 50 Nm. The idle speed is not critical and may
> be lower, so a similar power motor with a different gearing should be ok.
>
> The other problem is that this particular motor has a plastic gear that is
> designed as a "mechanical fuse" to prevent burning out of the motor. The
> connection between that gear and the output shaft sometimes strips off,
> probably when there's a mechanical backlash on the output shaft.
>
> So I'm looking for a gear motor (or a gear + motor combo) in that power
> range (should not be less power, but may be somewhat more) with a higher
> stall torque, a solid gearing (ideally some kind of metal) and an idle
> speed that's at least 80 rpm or so.
>
> The final purpose is to move a push/pull cable back and forth. We generate
> this linear movement through a lever mounted to the motor shaft. So in
> theory a linear actuator could also do it. The problem with most actuators
> we have is twofold: one is the overall length; they tend to be much longer
> than we have space for. We need a total movement of ~70mm and have around
> 160mm space, lengthwise. Linear actuators tend to be longer. The other
> problem is that most of them are much slower. In the current application,
> the mounting point at the lever moves the distance in some 200 ms (at half
> load). But one that fits and that is fast enough could be even better.
>
> And of course I don't have several hundred dollars to spend on that :)  The
> one we're using now costs around $50. Small production quantities (several
> hundred per year). Final destination is USA.
>
> Does anybody know where I can find such a gear motor or gear+motor combo
> (or linear actuator)? I've looked a lot, but they either are made for
> different voltage (24+V or AC), are much slower (<10rpm) or faster (and
> therefore weaker), or much more expensive.
>
> Thanks for any hints,
> Gerhard
>

> Hello,
>
> we're currently using this gear motor in a servo-type application:
> http://www.casaferreira.com.br/pdf/CEP453042.pdf
>
> 12VDC, 57W, nominal 9Nm/75rpm/18A, stall 36Nm/50A, idle speed 100rpm, gear
> 63:1
>
> There are two problems I need to solve. One is that the stall torque is not
> enough. Ideally it would have 50 Nm. The idle speed is not critical and may
> be lower, so a similar power motor with a different gearing should be ok.
>
> The other problem is that this particular motor has a plastic gear that is
> designed as a "mechanical fuse" to prevent burning out of the motor. The
> connection between that gear and the output shaft sometimes strips off,
> probably when there's a mechanical backlash on the output shaft.
>
> So I'm looking for a gear motor (or a gear + motor combo) in that power
> range (should not be less power, but may be somewhat more) with a higher
> stall torque, a solid gearing (ideally some kind of metal) and an idle
> speed that's at least 80 rpm or so.
>
> The final purpose is to move a push/pull cable back and forth. We generate
> this linear movement through a lever mounted to the motor shaft. So in
> theory a linear actuator could also do it. The problem with most actuators
> we have is twofold: one is the overall length; they tend to be much longer
> than we have space for. We need a total movement of ~70mm and have around
> 160mm space, lengthwise. Linear actuators tend to be longer. The other
> problem is that most of them are much slower. In the current application,
> the mounting point at the lever moves the distance in some 200 ms (at half
> load). But one that fits and that is fast enough could be even better.
>
> And of course I don't have several hundred dollars to spend on that :) The
> one we're using now costs around $50. Small production quantities (several
> hundred per year). Final destination is USA.
>
> Does anybody know where I can find such a gear motor or gear+motor combo
> (or linear actuator)? I've looked a lot, but they either are made for
> different voltage (24+V or AC), are much slower (<10rpm) or faster (and
> therefore weaker), or much more expensive.
>
> Thanks for any hints,
> Gerhard
>

>
> Pearce, AB (Alan) wrote:
>
> >>So I'm looking for a gear motor (or a gear + motor combo)
> >
> > Your local motor vehicle dealer scrap yard?
> >
> > A starter motor initially came to mind,
>
> I think they are too fast and too big. I'd need a gear, for which I don't
> yet have a cheap enough solution.
>
> > but a windscreen wiper motor would do.
>
> Something like this is what we're using now. The problem I'm seeing is
> that
> our torque requirements seem to be just a bit above what most wiper motors
> produce, so I probably have to try many of them until I find one -- if I
> find one.
>
> Anybody knows where to find datasheets of windshield wiper motors? What
> would get me started is stall torque and idle speed... Ideally a list of
> all the motors of one of those replacement parts manufacturers with that
> data :)
>
> Thanks,
> Gerhard
>

> >>So I'm looking for a gear motor (or a gear + motor combo)
> >
> > Your local motor vehicle dealer scrap yard?
> >
> > A starter motor initially came to mind,
>
> I think they are too fast and too big. I'd need a gear, for
> which I don't yet have a cheap enough solution.
>
> > but a windscreen wiper motor would do.
>
> Something like this is what we're using now. The problem I'm
> seeing is that our torque requirements seem to be just a bit
> above what most wiper motors produce, so I probably have to
> try many of them until I find one -- if I find one.
>
> Anybody knows where to find datasheets of windshield wiper
> motors? What would get me started is stall torque and idle
> speed... Ideally a list of all the motors of one of those
> replacement parts manufacturers with that data :)
>
> Thanks,
> Gerhard

>
> Tony Smith wrote:
>
> > What about a winch?  Like on the front of 4-wheel drive vehicles?
>
> Alan Smith already suggested this. What I answered to him is still valid:
>
> "That might be another venue. I started a quick search, and so far
> everything I've seen was way too heavy, way too strong and most of it also
> way too expensive. But there probably are some in the range I'm looking
> for
> -- "just" a matter of finding them :)"
>
> Thanks,
> Gerhard
>

>
> An advise to myself: read before speak :-)
>
> Tamas
>
>
> On 20/10/06, Gerhard Fiedler <listsspam_OUTconnectionbrazil.com> wrote:
> >
> > Tony Smith wrote:
> >
> > > What about a winch?  Like on the front of 4-wheel drive vehicles?
> >
> > Alan Smith already suggested this. What I answered to him
> is still valid:
> >
> > "That might be another venue. I started a quick search, and so far
> > everything I've seen was way too heavy, way too strong and
> most of it
> > also way too expensive. But there probably are some in the
> range I'm
> > looking for
> > -- "just" a matter of finding them :)"
> >
> > Thanks,
> > Gerhard
> >
> > --

>
> Pearce, AB (Alan) wrote:
>
> >> What this site seems to call "high torque" is a magnitude or more below
>
> >> what we need. But checking out robotics sites may lead to something...
> >
> > Maybe what you need are the sort of motors that used to used on reel to
> > reel mag tape units on computers, but all the ones I saw were operated
> > on 24V.
>
> This is what I'm also finding with the robotics sites. Most of them have
> only motors that are way below my specs. (To summarize quickly: 12 V DC,
> stall torque >50 Nm = 450 lbf in = 7200 ozf in, electric power ~60 W,
> stall
> current probably ~50 A, idle speed >80 rpm).
>
> The ones that fall into this range are almost all speced for 24 V or more.
> Which makes sense -- but not in an automotive application :)
>
> Gerhard
>

> Tony Smith wrote:
>
>  
>> What about a winch?  Like on the front of 4-wheel drive vehicles?
>>    
>
> Alan Smith already suggested this. What I answered to him is still valid:
>
> "That might be another venue. I started a quick search, and so far
> everything I've seen was way too heavy, way too strong and most of it also
> way too expensive. But there probably are some in the range I'm looking for
> -- "just" a matter of finding them :)"
>
> Thanks,
> Gerhard
>
>  

>
> Austin wrote:
>
> >> everything I've seen was way too heavy, way too strong and most of it
> >> also way too expensive. But there probably are some in the range I'm
> >> looking for -- "just" a matter of finding them :)"
> >
> > ATV winches.
> >
> > One site I came across with a few specs:
> > http://www.gorillawinches.com
>
> Thanks for the pointer. What I saw was not encouraging, though...
>
> http://tinyurl.com/y84se9 : At $130 that could almost fit into the budget,
> 6 kg might be bearable. The data provided was not too extensive, other
> than
> that it is a 1 hp (750 W) motor. That is plenty for my application,
> actually quite an overkill. I found a bit more data for a sister-winch:
>
> http://tinyurl.com/upxjm : Here they have a load/speed table. I don't know
> the spool diameter, but I estimated with at least 10 cm. This gives an
> idle
> speed of max. 22 rpm -- which is too slow. Probably there are not many
> winches that are much faster: I'd need it around 80 rpm, four times the
> speed.
>
> Am I wrong with this estimation? Are there winches that rotate at 80 rpm?
> I
> don't have a lot of experience with ATV winches.
>
> Thanks,
> Gerhard
>

> >Gerhard Fiedler
>>everything I've seen was way too heavy, way too strong and most
>>of it also way too expensive. But there probably are some in
>>the range I'm looking for -- "just" a matter of finding them :)"
>
> ATV winches.
>
> One site I came across with a few specs:
> http://www.gorillawinches.com
>
> Austin
>
>
> ----- Original Message -----
> From: "Gerhard Fiedler" <TakeThisOuTlistsEraseMEspam_OUTconnectionbrazil.com>
> To: <RemoveMEpiclistTakeThisOuTmit.edu>
> Sent: Friday, October 20, 2006 6:38 AM
> Subject: Re: [EE] Looking for 12VDC high-torque motor
>
>
> Tony Smith wrote:
>
>> What about a winch?  Like on the front of 4-wheel drive vehicles?
>
> Alan Smith already suggested this. What I answered to him is still valid:
>
> "That might be another venue. I started a quick search, and so far
> everything I've seen was way too heavy, way too strong and most of it also
> way too expensive. But there probably are some in the range I'm looking
> for
> -- "just" a matter of finding them :)"
>
> Thanks,
> Gerhard
>

> Lee McLaren wrote:
>
>  
>> Check out the geared 250W motor.
>>
>> http://www.oatleyelectronics.com/motors.html
>>    
>
> If you're talking about the SC250G, it's a 24V motor -- like so many others
> in this class that I've come across. I'm not sure how the torque/speed
> curve behaves when halving the voltage. Does anybody have experience with
> this, or pointers?
>
> Thanks,
> Gerhard
>
>  

> > Largish stepper motors can be had fairly cheaply.  At the
> RPM you're
> > after they'd work nicely.  Downside is you need to make drivers for
> > them.  Not hard, but a bit of a nuisance and pushes the cost up
> > somewhat.  The simplest driver is for unipolar motor (6
> wire) and is 4
> > fets and a bit of logic.
>
> I've trouble finding a stepper motor that can produce 50 Nm
> (7000+ ozf.in).
> The biggest I found have a holding torque of 40 Nm (5700
> ozf.in), which is a bit more than what we have now (as stall torque).
> www.anaheimautomation.com/hightorque.htm
>
> Are there stronger stepper motors?
>  
> How does the holding torque of a stepper motor relate to the
> stall torque of a DC motor? One site says that "dynamic
> torque" is about 70% of holding torque. Is "dynamic torque"
> what I have available to move something? (I know that the
> available torque goes down with speed, but since I'm working
> at around 1 rot/s, it seems that is very slow for a typical
> stepper motor and it develops its maximum torque.)

>
> > > Largish stepper motors can be had fairly cheaply.  At the
> > RPM you're
> > > after they'd work nicely.  Downside is you need to make drivers for
> > > them.  Not hard, but a bit of a nuisance and pushes the cost up
> > > somewhat.  The simplest driver is for unipolar motor (6
> > wire) and is 4
> > > fets and a bit of logic.
> >
> > I've trouble finding a stepper motor that can produce 50 Nm
> > (7000+ ozf.in).
> > The biggest I found have a holding torque of 40 Nm (5700
> > ozf.in), which is a bit more than what we have now (as stall torque).
> > www.anaheimautomation.com/hightorque.htm
> >
> > Are there stronger stepper motors?
> >
> > How does the holding torque of a stepper motor relate to the
> > stall torque of a DC motor? One site says that "dynamic
> > torque" is about 70% of holding torque. Is "dynamic torque"
> > what I have available to move something? (I know that the
> > available torque goes down with speed, but since I'm working
> > at around 1 rot/s, it seems that is very slow for a typical
> > stepper motor and it develops its maximum torque.)
>
>
> Ok, your definition of 'largish' is different to mine :)
>
> There are bigger steppers, the next size up from a NEMA42 is a NEMA66, but
> it starts getting a bit silly.  The body of that is bigger than a CD-ROM!
> You could bolt a gearhead to the stepper, at low RPM you tend not to loose
> too much torque.  Given the prices on this page
> <www.powerdrives.com/superior/order/nema42gearheads_rtplanetary.htm
> >,
> that's probably not an option.
>
> Not sure what they mean by dynamic torque, as you say torque varies with
> speed.  Most steppers have a torque curve that remains fairly flat up to a
> certain speed, and then falls off rapidly, a bit like a knee.  Maybe the
> 70%
> refers to that point.
>
> Looks like your stuck with trading speed for torque, get a motor and gear
> it
> down.  Servos on CNC machines are usually geared down (say 1:5), so
> pulleys
> & belts are common.
>
> 50Nm is a lot of torque, what are you making?
>
> Tony
>

> we're currently using this gear motor in a servo-type application:
> www.casaferreira.com.br/pdf/CEP453042.pdf
>
> 12VDC, 57W, nominal 9Nm/75rpm/18A, stall 36Nm/50A, idle speed 100rpm, gear
> 63:1
>
> There are two problems I need to solve. One is that the stall torque is not
> enough. Ideally it would have 50 Nm. The idle speed is not critical and may
> be lower, so a similar power motor with a different gearing should be ok.
>
> The other problem is that this particular motor has a plastic gear that is
> designed as a "mechanical fuse" to prevent burning out of the motor. The
> connection between that gear and the output shaft sometimes strips off,
> probably when there's a mechanical backlash on the output shaft.
>
> So I'm looking for a gear motor (or a gear + motor combo) in that power
> range (should not be less power, but may be somewhat more) with a higher
> stall torque, a solid gearing (ideally some kind of metal) and an idle
> speed that's at least 80 rpm or so.
>
> The final purpose is to move a push/pull cable back and forth. We generate
> this linear movement through a lever mounted to the motor shaft. So in
> theory a linear actuator could also do it. The problem with most actuators
> we have is twofold: one is the overall length; they tend to be much longer
> than we have space for. We need a total movement of ~70mm and have around
> 160mm space, lengthwise. Linear actuators tend to be longer. The other
> problem is that most of them are much slower. In the current application,
> the mounting point at the lever moves the distance in some 200 ms (at half
> load). But one that fits and that is fast enough could be even better.
>
> And of course I don't have several hundred dollars to spend on that :)  The
> one we're using now costs around $50. Small production quantities (several
> hundred per year). Final destination is USA.
>
> Does anybody know where I can find such a gear motor or gear+motor combo
> (or linear actuator)? I've looked a lot, but they either are made for
> different voltage (24+V or AC), are much slower (<10rpm) or faster (and
> therefore weaker), or much more expensive.

> > is not enough. Ideally it would have 50 Nm. The idle speed is not
> > critical and may be lower, so a similar power motor with a
> different gearing should be ok.
> >
> > The other problem is that this particular motor has a plastic gear
> > that is designed as a "mechanical fuse" to prevent burning
> out of the
> > motor. The connection between that gear and the output
> shaft sometimes
> > strips off, probably when there's a mechanical backlash on
> the output shaft.
>
>
> My current thought is to use a normal 12VDC ~60W motor and
> drive a threaded bolt, making a custom linear actuator. The
> linear actuators I found that work this way are usually too
> slow. I'll see whether there's a reason for that... I need at
> least 10 cm/s, ideal would be 20 cm/s.
>
> Another possibility would be to continue using my gear motor
> and drive a belt. That would also get me more force on the
> cable than I have now.
>
> Gerhard

> > As a complete aside on simple ideas, I recently discovered how the
> > tracks are kept taut on bulldozers, not that I'd ever wondered.  On
> > most motorcycles, to remove slack in the chain you loosen the rear
> > axle, slide the wheel back, and re-tighten.  On a
> bulldozer, it's hydraulic.
> > Rather than pressure being applied by air or springs, it's
> by grease.
> > When the track becomes loose, you just pump in more grease.  The
> > grease can't be compressed, so the tension is maintained.  Rather
> > neat, I thought.  I've contemplated making this work on a bike.
>
> Calling a grease-driven mechanism "hydraulics" is stretching
> it a bit :)
>
> On a bike, you'd probably have the problem of having to
> synchronize the movement on both sides of the axle. Not a
> problem for bulldozers.
>
> Gerhard