Electric RPM Question

[MacPhreak]

hey guys,

got a good question for y'all.

I have a Clod Buster and will be buying 2 modified motors for it. Now
the thing that concerns me is how the hell do I manage to adjust the
motors so they are timed exactly the same are at least real close. Also
is there a Tachometer out there that I could use to calibrate them
keeping in mind that one motor will be reversed rotation.



MacPhreak

[Jonathan Hodgson]

On Wed, 01 Mar 2006 21:48:03 -0500, MacPhreak wrote:

> I have a Clod Buster and will be buying 2 modified motors for it. Now
> the thing that concerns me is how the hell do I manage to adjust the
> motors so they are timed exactly the same are at least real close. Also
> is there a Tachometer out there that I could use to calibrate them
> keeping in mind that one motor will be reversed rotation.

Personally, I don't think it would matter that much. Since both motors
will be driving the truck forward, they'll both be dragged well below
their no-load speed, and I don't see that it makes a difference if one's
pulling slightly more current than the other.

In fact, you might even *choose* to have different characteristics at
each end - after all, when you accelerate the weight will transfer to
the rear wheels, and if you brake or reverse then the front wheels will
be doing more of the work...

Jonny

[MacPhreak]

Jonathan Hodgson wrote:
> On Wed, 01 Mar 2006 21:48:03 -0500, MacPhreak wrote:
>
>
>> I have a Clod Buster and will be buying 2 modified motors for it. Now
>>the thing that concerns me is how the hell do I manage to adjust the
>>motors so they are timed exactly the same are at least real close. Also
>>is there a Tachometer out there that I could use to calibrate them
>>keeping in mind that one motor will be reversed rotation.
>
>
> Personally, I don't think it would matter that much. Since both motors
> will be driving the truck forward, they'll both be dragged well below
> their no-load speed, and I don't see that it makes a difference if one's
> pulling slightly more current than the other.
>
> In fact, you might even *choose* to have different characteristics at
> each end - after all, when you accelerate the weight will transfer to
> the rear wheels, and if you brake or reverse then the front wheels will
> be doing more of the work...
>
> Jonny

It's not a question of current. It's all about the speed.

I tend to differ on front to rear difference where if the rear is slower
than the front then it will constantly be in skid mode. This would wear
out the tires faster and make the truck harder to control. i have tried
to install motors with a fixed timing and therefore the rear one was
slower being run in reverse. It literally looks like the rear is being
dragged around. While somewhat entertaining to a point it is also very
annoying when trying to actually drive it correctly. On an other note it
may not be a big deal if they are only slightly off but considering the
precise visual adjustment guides that electric motors have (Sarcasm) and
the tendency for them to be slightly different from one motor to an
other I would think it would be difficult to get them reasonably close
in timing. Reasonably being +/- 300 rpm and even that would be an issue
to me.

It would be the same as running different sized tires on front and back
on any 4WD vehicle unless of course you have a center diff to
compensate. But this would mean your diff would be working overtime as well.


I may just have to make a Tachometer myself.


MacPhreak

[sonofabitchsky@hotmail.com]

MacPhreak wrote:
> Jonathan Hodgson wrote:
> > On Wed, 01 Mar 2006 21:48:03 -0500, MacPhreak wrote:
> >
> >
> >> I have a Clod Buster and will be buying 2 modified motors for it. Now
> >>the thing that concerns me is how the hell do I manage to adjust the
> >>motors so they are timed exactly the same are at least real close. Also
> >>is there a Tachometer out there that I could use to calibrate them
> >>keeping in mind that one motor will be reversed rotation.
> >
> >
> > Personally, I don't think it would matter that much. Since both motors
> > will be driving the truck forward, they'll both be dragged well below
> > their no-load speed, and I don't see that it makes a difference if one's
> > pulling slightly more current than the other.
> >
> > In fact, you might even *choose* to have different characteristics at
> > each end - after all, when you accelerate the weight will transfer to
> > the rear wheels, and if you brake or reverse then the front wheels will
> > be doing more of the work...
> >
> > Jonny
>
> It's not a question of current. It's all about the speed.
>
> I tend to differ on front to rear difference where if the rear is slower
> than the front then it will constantly be in skid mode. This would wear
> out the tires faster and make the truck harder to control. i have tried
> to install motors with a fixed timing and therefore the rear one was
> slower being run in reverse. It literally looks like the rear is being
> dragged around. While somewhat entertaining to a point it is also very
> annoying when trying to actually drive it correctly. On an other note it
> may not be a big deal if they are only slightly off but considering the
> precise visual adjustment guides that electric motors have (Sarcasm) and
> the tendency for them to be slightly different from one motor to an
> other I would think it would be difficult to get them reasonably close
> in timing. Reasonably being +/- 300 rpm and even that would be an issue
> to me.
>
> It would be the same as running different sized tires on front and back
> on any 4WD vehicle unless of course you have a center diff to
> compensate. But this would mean your diff would be working overtime as well.
>
>
> I may just have to make a Tachometer myself.
>
>
> MacPhreak

Get a tach. Seems like you won't be happy unless they are dialed in.
Problem will be as the brushes wear, the motors will start to you out
of sync.