Quote:
Originally Posted by squirrel
But I would be even more concerned that "fixing" a shorted winding will melt the wire and open it, so the motor will only be running on 80% of it's windings.
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This is worth a test.
And if it comes back that that's how the fix works—by severing a winding—then BaneBots should damned well have disclosed that fact. (Not knowing is negligence, not an excuse. I want to give them the benefit of the doubt: maybe their supplier was lying to them about the presence of debris, or maybe this one motor is not representative of the failure mode that they'd encountered. But if BaneBots came up with the fix, it's their responsibility to explain the issue and resolution accurately and completely.)
I don't know the nature of BaneBots supplier arrangement with FIRST;* if they're donating the parts for free, or heavily discounting them, then I understand that we shouldn't ask too much of them. But if FIRST is a paying customer, I think that it would be reasonable to forward BaneBots a summary of the motor rules, with the explanation that all FRC teams are very strictly limited as to what they can and can't do, and that if BaneBots wants to do business, they need to provide somewhat better service. (
Aside: actually, I support the idea of being able to repair parts in principle, so the recent team update was a good result. There are too many high-value or high-lead-time items that can fail and seriously disadvantage a team. As long as it's clear the repairs don't rise to the level of a significant functional change, I'm on board.)
This is not to minimize the impact of the corrective actions BaneBots has taken in the past with regard to their products—I'm sure that resolving those issues was stressful and complicated, not to mention costly. But the fundamental flaw those times was misspecification: for example, they hadn't provided accurate information on how to safely use the gearboxes. (Granted, in the case of the bad CIM boxes, if they'd done so, they wouldn't have sold any for drivetrains, because they would have had to publish specs indicating their parts were unlikely to be up to that task.)
In fact, let's consider the problems associated with BaneBots products in FRC applications (am I missing or mischaracterizing anything?):
- 2007: Failures reported on BaneBots high-reduction planetary gearboxes (36 mm & 42 mm sizes); BaneBots has since updated their specifications to warn against high-torque load cases, and released new lines of gearboxes that are apparently more durable
- 2007: BaneBots CIM gearboxes with defective planet carrier plates; BaneBots designed replacement (more durable) carriers
- 2009: Without advising purchasers, BaneBots substituted RS-545/RS-385 motors that didn't match the ones depicted on their website (listed as FIRST-legal), and more importantly, were different from the RS545PH-5125F model in the KOP; never explicitly resolved, but hopefully never happens again (we never found out what the specs on the plastic-endcapped RS-545 motors were)
- 2011: RS-775 motors are frequently defective as supplied
- 2011: Lead times of up to 3 weeks on some gearboxes
So what's the root cause here? Want to bet that it has something to do with not testing their products adequately for FRC applications? And maybe there's some unfamiliarity with just what they're being asked to provide, as an FRC supplier—e.g. have enough stock of the right motors (or be able to get them fast), and communicate with FRC HQ when your supply chain breaks down (instead of trying to pass off non-compliant materiel, or delaying shipments). (It's possible that FRC HQ hasn't communicated these expectations, perhaps because they see things differently; if that's the case, I'm interested in their position on the matter.)
Part of being in business is managing inventory and deliveries—and while it's a company's prerogative to choose to keep low inventory and impose long lead times, it's their customers' prerogative to not choose that company the next time they have a critical project. Similarly, while their low prices are great, I'm certain that the majority of FIRST teams are willing to concede that a little extra cost to ensure quality in a critical component like a motor or gearbox is a good thing. After all, isn't that a big reason why AndyMark products are so popular, despite their often-higher prices? (Along with excellent service and innate familiarity with FRC.) Isn't that why people will pay $25 to $28 for a CIM motor that virtually never fails?
Maybe BaneBots needs to concentrate on being a little more like AndyMark or IFI, or else consider taking a step back from their current role as a critical FRC supplier?
*
Why don't I know this? Is there really any harm in disclosing this fact? After all, the benefit of disclosure is that it calibrates the community's expectations.