Banebots RS-775 Case Short

[Bochek]

This is all very scary to read. We just ordered 4 of these motors. And where planing on using 2 on the robot.

Gonna have to test them out heavily before competition.

Has anyone experimented with trying to fix the shorts?

- Bochek

[Tom Bottiglieri]

Originally Posted by Dale(294engr]

(theoretical remedy: electrically isolate each motor to pass inspection, but problem will likely escalate as more turns shorted draws higher current & produces less torque; high localized heating leads to catastrophic smoke)

This is a pretty important point. Just isolating the motors won't fix all of the issues. These motors do get worse over time and will fail, regardless if they are shorted to your frame.

[team222badbrad]

I shipped two of the four defective ones received back to BaneBots. We are awaiting the replacements. Once we get them we will let you know the prognosis.

Let's hope the these motors can at minimum spin...

I'd say it's pretty bad when you get a motor that can't even spin. I wouldn't doubt it was caused by poor packaging as our four 775's were shipped in a USPS small flat rate box.

Also we have noticed over the years that BaneBots enjoys "throwing" components in small flate rate Priority mail boxes. If I recall they shipped our planetary gearboxes last year like this with no padding and the box was bulging because they barely fit.

Poor quality control, long lead times (at least for us last year), and poor packaging. I don't blame anyone who has or is considering not using BaneBots as a robot part supplier. The same applies in the real world.

[Tristan Lall]

Originally Posted by team222badbrad

I'd say it's pretty bad when you get a motor that can't even spin. I wouldn't doubt it was caused by poor packaging as our four 775's were shipped in a USPS small flat rate box.

Brilliant work, BaneBots. You've obviously figured out how to make a shipping box larger on the inside than on the outside.

An RS-775 motor is Ø1.85 in. A USPS small flat rate box is for items up to 1.625 in thick. That leaves -0.113 in for padding on each side of the motor.

Let's see if BaneBots owns up to the packaging error, and provides free (working!) replacements in a timely fashion.

[Jeff Rodriguez]

WE got two 775s in and both of them are good. No signs of any defects.

[R.C.]

Originally Posted by Karthik

Four brand new motors arrived today. All shorted. I'd call this the first sign of trouble...

http://desmond.yfrog.com/Himg736/sca...=640&ysize=640

We will not be using any RS-775 motors this year.

We ordered 2 775's and 15 550's. 550's were all good, both 775's were bad. We are definitely not using 775's this year.

My kids followed your lead and did the same...

We used 775's all last year and had zero issues till the offseason and offseason presentations. Its pretty embarrassing when your robot won't work in front of a sponsor who donates over ($5,000) a year due to case shorts... We fixed the issue by swapping to a new 775.

Chris and others, 550's are some awesome motors and the cimulator/p60's are awesome as well. Don't rule out a supplier because of one issue, I know its a big issue but 550 are very good motors.

-RC

[Jared Russell]

A manufacturing issue resulting a large number of defective motors is understandable; it happens to every supplier at one point or another. But continuing to sell the defective products to teams a full year later is just unbelievable.

I am very happy that the 2012 parts utilization rules make building a high-performing robot without BaneBots products an option.

[MrForbes]

Originally Posted by Jared341

But continuing to sell the defective products to teams a full year later is just unbelievable.

That's where I'm coming from

[Ether]

Originally Posted by Karthik

at the first sign of trouble they'll be introduced to our arbor press.

Instead of crushing them, could I talk you into frying them instead? Hook them up to 12 volts and let us know how long it takes to release the factory smoke. That might be a useful bit of data for folks who are considering using them on drivetrain.

[Mrpalmere]

The RS-775 motors have a know issue with a short to thr frame. The easy fix is to run 12v from terminal to frame. Do this independently from the other terminal. If there is indeed a short to the frame, it won't be after you do this process. We had this issue last year and shorted each terminal, independently, to the frame of the motor and ran those motors all season with no problem.

[Ether]

Originally Posted by Mrpalmere

We had this issue last year and shorted each terminal, independently, to the frame of the motor and ran those motors all season with no problem.

I'm sure you meant "applied 12 volts between" instead of "shorted".

[Karthik]

Originally Posted by Ether

Instead of crushing them, could I talk you into frying them instead? Hook them up to 12 volts and let us know how long it takes to release the factory smoke. That might be a useful bit of data for folks who are considering using them on drivetrain.

We locked the motor and hooked it up to a 12V battery. The magic smoke was released approximately 0.5 seconds after stall, perhaps less.

[Ether]

Originally Posted by Karthik

We locked the motor and hooked it up to a 12V battery. The magic smoke was released approximately 0.5 seconds after stall, perhaps less.

Thank you.

[theprgramerdude]

Originally Posted by Karthik

We locked the motor and hooked it up to a 12V battery. The magic smoke was released approximately 0.5 seconds after stall, perhaps less.

Do you happen to have a spare RS-550 laying around to test the same thing with?

[Ether]

Originally Posted by theprgramerdude

Do you happen to have a spare RS-550 laying around to test the same thing with?

The 775-18 is 273 watts at stall at 12 volts.

The 550 is 254 watts at stall and is much less massive than the 775-18.

Read this thread:
http://www.chiefdelphi.com/forums/sh...7&postcount=34