Quote:
Originally Posted by Nemo
How do you know?
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If you want to be able to push indefinitely, your motors can't draw more than 40 amps* each while pushing, or else you'll begin to trip the auto-resetting breakers on the PDB. The 160A total current draw across 4 CIMs is a lot, but not enough to immediately (or even quickly) trip a functional 120A breaker. The speed that roughly correlates with traction limited at 40 amps, for an at weight robot using high traction wheels, is ~5.5 feet per second.
You can definitely still push if your drive isn't geared that slowly for a variety of reasons. For one, circuit breakers don't trip immediately. There are also quite a lot of factors in play during each individual pushing match that affect how successful it will be - wheel traction, pre-existing heat in the motors, chassis rigidity, center of gravity, weight transfer between robots, etc. But if you design a two-speed transmission with a low gear that is traction limited near 40A, you can be confident that you'll always be able to push as well as you're able. This is one of the major selling points of two speed transmissions.
*In reality, the snap-action breakers have a huge safety margin, so there's some wiggle room here.