Uses for New x1688a Power Functions Train Motor?

[DLuders]

Can anybody think of a possible use of the new x1688a "Electric, Train Motor 9V RC Train with Integrated PF Attachment, Orange Wheel Holders" ? If used with the 64227 "Electric, Power Functions IR Speed Remote Control Unit" (shown below), perhaps the train motor could be used in the upper part of an excavator's digger arm to rotate liftarms? It's small and the two axle holes might come in handy to raise the roof on a Technic Supercar, open gullwing doors, etc.

The characteristics of the train motor are shown on Philo's 9V Motor Comparison Page. It turns at 1900 RPM , weighs 57 grams, has a Stalled Torque of 3.6 N.cm , and a Stalled Current of 1.3 Amps. It COULD BE USEFUL in Technic applications. Any ideas?

[Pauger]

Frankly it seems quite useless to me; it's rpm is way to high and torque to low, it's to big and not suitable for studless building. And I assume the two axles can't be controlled independently?

I might be wrong though.

Edited July 29, 2010 by Pauger

[andythenorth]

Windscreen wipers

[CP5670]

Frankly it seems quite useless to me; it's rpm is way too high and torque too low, it's too big and not suitable for studless building.

This is sometimes a good thing actually. There are situations where a high RPM is useful, and it's more efficient to gear down a fast but weak motor than to gear up a slow but powerful one. Although the shape of this motor is indeed clunky for Technic models.

[Pauger]

There is abselutely no situations as i know of where you need 1900rpm, and where such a low amount of torque is sufficient... except for maybe if you're trying to build a LEGO smoothie machine?

Hmmm... i wonder if anyone has ever done that?

[Silcantar]

There is abselutely no situations as i know of where you need 1900rpm, and where such a low amount of torque is sufficient... except for maybe if you're trying to build a LEGO smoothie machine?

Hmmm... i wonder if anyone has ever done that?

It could be useful for a twin-motor airplane. You don't need much torque to turn propellers.

[CP5670]

There is abselutely no situations as i know of where you need 1900rpm, and where such a low amount of torque is sufficient... except for maybe if you're trying to build a LEGO smoothie machine?

Hmmm... i wonder if anyone has ever done that?

There are times when the PF XL and M motors are too slow and need to be geared up. You probably won't need 1900 RPM but the point is that it's more efficient to get, say, 1900 RPM down to 700 RPM rather than 275 RPM up to 700 RPM. I'm thinking of cases where the final speed of whatever you want to operate is low, but a high speed is needed at some intermediate point in the geartrain. For example, the 8043 excavator has an issue where moving the turntable a lot also causes the treads to move slightly. If the model had faster motors along with more gear reduction in the base, it would minimize this effect.

A smoothie machine would be interesting though.

[dr_spock]

You could make a Lego cake batter mixer with it.

[andythenorth]

The PF XL motor will happily destroy transmission components like gears and universal joints. A stalled PF XL motor has enough torque to visibly bend liftarms.

A motor with higher RPM and less torque, geared down massively at the final stage will put less stress throughout the model. I'm not suggesting that makes the train motor useful for Technic, it's just an extra comment :)

[Silcantar]

Probably less useful than the E-Motor in any case, though. It does have more than double the RPM of the E-motor and 80% of the torque, though. The greater power may make up for the larger size and awkward shape.

Edited July 30, 2010 by Silcantar

[DLuders]

@ Silcantar: I didn't even know that a Lego "E-Motor" even existed! From the link you provided above, "The E-Motor is a 9V motor with an internal gearbox. Its 9.5:1 gearing ratio provides a maximum torque of 4.5 Ncm and approximately 800 rotations per minute without load. It also functions as a very efficient generator." It must be new, because neither of the "W979670" or "979670" part numbers are in the Bricklink or Peeron catalogs, and the Lego Education Store website says that they're out of stock.

[Pauger]

It could be useful for a twin-motor airplane. You don't need much torque to turn propellers.

Aha! didn't think about that, still a very awkward shape though.

There are times when the PF XL and M motors are too slow and need to be geared up. You probably won't need 1900 RPM but the point is that it's more efficient to get, say, 1900 RPM down to 700 RPM rather than 275 RPM up to 700 RPM. I'm thinking of cases where the final speed of whatever you want to operate is low, but a high speed is needed at some intermediate point in the geartrain. For example, the 8043 excavator has an issue where moving the turntable a lot also causes the treads to move slightly. If the model had faster motors along with more gear reduction in the base, it would minimize this effect.

Gearing down from such a high speed would use a lot of space and create more friction. However I agree there might be some situations where such a solution would work good.

[Burf2000]

Anyone got a e-motor yet? I do want to get that set!

[Mortymore]

E-motor comparison with other PF motors

The following information about XL and M motors was collected from Philos website

XL-Motor (8882): 40 N.cm / 220 rpm

M-motor (8883): 11 N.cm / 405 rpm

E-motor (W979670): 4.5 Ncm / 800 rpm

cumps

[Burf2000]

Well does anyone know if they hit bricklink yet?

[Silcantar]

Well does anyone know if they hit bricklink yet?

They aren't on Bricklink yet, and they're temporarily sold out at Lego Education US.

[DLuders]

You can buy them at Shop.Lego.com: http://shop.lego.com/ByTheme/Product.aspx?p=8866&cn=87&d=328 . For non-US customers, just change the "Country" in the dropdown menu on that website. Cost = USD 10.99 .

[CP5670]

They're referring to the E-motor, not the train motor.

You can alternatively just try the 9V RC motors, which are still widely available on Bricklink. They run at 900RPM and actually have a bit more mechanical power than the XL motors. They have an odd shape that's hard to fit into models compared to the PF motors though.

Edited August 5, 2010 by CP5670

[DLuders]

On this TechnicBRICKS Blogspot post, Conchas wrote about the 9760 Lego E-Motor. Amongst other things, he wrote,

"On the other way this one shouldn't be very useful as a LEGO Technic motor (unless for instance to build an high-speed fan) exactly because of its characteristics (low-torque/high-speed), when what we demand is exactly the opposite (high-torque/low-speed) - Eventual characteristics, for the the so desired S-motor...

"It shouldn't be a coincidence that...this new E-motor is not marketed as a Power Functions motor, like the M and XL versions on the same page, are! The prefix 'E' (Energy) is not suggesting any alignment with the other ones, which use size prefixes (M and XL). Also the 4x6x4 form factor, curved only at the topside, suggests a very specific use like in the Wind Power Generators."