Globe Motor Durability Versus RS-545

[de_]

Just wondering what everyone's experience with Globe motors is, preferrable in comparision with the RS-545. Some old data says the Globe is a 55w motor versus what some say is a 100w RS-545. However the Globe may be extremely conservatively rated given it is intended for applications that required 10+ year life. It does not have even a slot for air cooling of its brushes but maybe its brushes are way bigger and more rugged than usual.
Anyone pushed these motors at 8amp, 12 amps or higher ? Burnt any out ?

My experience with the RS-545 is if you start running close to 100w continously (8+ amps), you should have a cooling fan pointed at the brushes and you probably shouldn't expect a motor (brush) life of too long. But then a complete regional might only put on 40 minutes total use on the motor.

[AdamHeard]

Originally Posted by de_

Just wondering what everyone's experience with Globe motors is, preferrable in comparision with the RS-545. Some old data says the Globe is a 55w motor versus what some say is a 100w RS-545. However the Globe may be extremely conservatively rated given it is intended for applications that required 10+ year life. It does not have even a slot for air cooling of its brushes but maybe its brushes are way bigger and more rugged than usual.
Anyone pushed these motors at 8amp, 12 amps or higher ? Burnt any out ?

My experience with the RS-545 is if you start running close to 100w continously (8+ amps), you should have a cooling fan pointed at the brushes and you probably shouldn't expect a motor (brush) life of too long. But then a complete regional might only put on 40 minutes total use on the motor.

Completely unscientific, but based on my use of both motors; The globes can take a beating compared the the 545's. It may be because every time I've used the globes they are gearred down a LOT compared to the few times I've used the 545's. I've stalled globes a lot, even had them stalled the entire match more or less controlling an arm (not at full voltage though).

The 545's on our conveyor (a pair are geared with a pair of Fisher Prices) are stalled for a brief moment each match, and usually run on the free speed half of their curve, are somewhat damaged after a regional.

[martin417]

We have burned up at least one of each. Our intake roller was prone to jamming, and we burned up an RS545 in practice. After that, we put a speed sensor on the roller, and some code that would automatically reverse the roller in the event of a jam. Our shooter hood is driven by a Globe. The pot came unplugged, and the software was trying to drive the hood to a certain value, no one noticed, and after several minutes, a plume of smoke signaled the death of the Globe.

Both failures were the result of stalling the motor for an extended period. The Globe lasted much longer than the RS545.

[de_]

Thanks for the update.
I took a globe apart and yes, the brushes are pretty heavy duty, materially bigger, wider than what is on RS 54x motors I believe.

I forget the First rules. Are you allowed to put a different gearbox on a globe (though not easy with its big shaft) ? How about modify a globe gearbox to take out a gear set or 2 ? I really needed a ~25/1 globe. I believe it is currently a 117/1 planetary ?

Has anyone seen the KV, Io etc specs on the Globe ?

[MrForbes]

it's in the rules...somewhere...oh here...

<R53> So that the maximum power level of every ROBOT is the same, motors and servos used on the ROBOT shall not be modified in any way, except as follows:
A. The mounting brackets and/or output shaft/interface of the motors may be modified to facilitate the physical connection of the motor to the ROBOT and actuated part.
B. The gearboxes for the Fisher-Price and Globe motors are not considered “integral” and may be separated from the motors.

is what you want in here?

[Al Skierkiewicz]

The transmission is not considered part of the motor so it may be modified/removed.

[AJ R]

It is legal to modify the gearbox on the globe motor. Post 8 in this thread has the gear ratios calculated out.
http://www.chiefdelphi.com/forums/showthread.php?t=42539&highlight=globe+stage
There are other threads that explain how to modify them.

[ajlapp]

Since the introduction of the globe motor in 2000 or 2001 I've never seen one failed or ever had a single issue with the motor or gearbox!

I have the same motor, or a very similar version on my 1999 S-10 4wd transfer case......it has performed flawlessly for 188,000 miles.

[Lil' Lavery]

I've never used the 545, but I have used the globe motor.
While I've never attempted to modify the transmission on the globes, my teams have used them multiple times without a single problem (issues with shock loads on our post-transmission gearing cropped up well before the globe motors themselves had issues).
The only thing close to a problem was the d-shaft, and an improperly machined gear that was attached to it.

[AndyH]

Team 1098 has been to 2 regionals and have burned up 3 545s. We have run several matches with a globe stalled and even had it smoking a little (practice day at the first regional). We had someone run to the van and get an extra globe and never used it. We are still running "smokey" and it is still working great.

[nahstobor]

In my 4 years of first I have had a Cim fail, multiple Fisher prices fail, a Denso fail but NEVER a Globe. I'm sad I couldn't find a use for the globe motor this year though, it would be the last thing on the robot that could fail.

[Jimmy Cao]

In my experience, all the banebots motors do not do well once they are stalled (esp at high voltages). Our floorload roller is powered by a 545, and they smoke really quickly if there is a jam and if the motor keeps trying to pull balls in, causing it to stall. After destroying a good 3 or 4, we decided to use a FisherPrice motor on our practice robot, to save some money.

Globe motors, however, have always been very durable, in my experience with them. I am yet to destroy one, even damage one. However, I do believe that they are not quite as powerful as the 545s.

[MrForbes]

We've never been able to find an application for the Globe motor, with our limited machining ability. Now that AndyMark sells shaft adapters, its more likely we could use it sometime...

We have used the Banebots motors, and as long as you don't put them where they can be stalled, and don't work them too hard, they do fine. We have two on the robot this year and they haven't cause any problems. One turns a small roller that slips if a ball gets stuck on it, the other turns the turret with a V belt, which slips when the turret hits the mechanical stop.

Sounds like the OP is looking to use the motors where they might be iffy, so Globe should be the way to go, assuming the transmission can be modified appropriately.

[Richard Wallace]

Originally Posted by squirrel

We've never been able to find an application for the Globe motor, with our limited machining ability. Now that AndyMark sells shaft adapters, its more likely we could use it sometime...

Thanks to Jabba the Hutt, we didn't need to wait for AndyMark to offer a solution. However, the AM part is more versatile.

Seriously, I have never seen a Globe fail. Smoke, yes; fail, no. We've used them in stock condition, with threads cut on the shaft-stub, and with one gearing stage removed.

I even tried to get the team to use one for extreme torque by chaining it to a rachet, but they haven't found a mechanism that can use that solution (yet).

[Adam Freeman]

67 modified a globe gearbox to speed up our conveyor system that feeds the "shooter". In this modified condition, the globe did not have enough torque to overcome our drivers aggression to load many balls into the conveyor quickly. The motor would become stalled and the drivers would have to reverse it to correct the issue. The globe motor never burned up even though it was stalled many times during practices.

We then replaced the globe with a RS-545 and a P60 64:1 gearbox. We competed at Cass Tech, then went to Lansing and lost a RS-545 during practice on Thursday b/c we stalled it out trying to pickup to many balls. We replaced the motor, competed at Lansing, then went to Troy and lost the RS-545 when we tried to pickup to many balls. We replaced it again and competed at Troy without issue.

The morale of the story is to not stall the RS-545 or you will be replacing it. Luckily, we have failed these motors at opportune times so far. I am sure we will lose another one before we are done with this robot. Odds are, sometime on Thursday at MSC.

We realize that we are asking this motor to do a little more than it is capable of, and we may burn it up if exercised too aggresively. Given the cost ($6/motor) and weight we are comfortable with the risk we are taking.

The P60 gearbox though is top notch! Light weight and compact.