Quote:
Originally Posted by cbale2000
Out of curiosity, how would a 2CIM + 2 MiniCIM drive compare? I've often wondered if this was a practical weight saving option or if the performance drop would make it not worth the trouble.  |
Do you mean 1+1 on each side compared to 2+0, or 2+2 on each side compared to 3+0?
Edit: I'm going to presume the first, as you're discussing a performance drop. I'll get back to you, but I seem to recall that it was a performance hit, but much closer to 2 CIMs than 1 CIM.
Edit2: By assuming a budget of 100A on one side of the drive train, the 2 CIM can deliver 627W at 3365 rpm, the 1+1 494W at 3638 RPM, and a 0+2 can deliver 425W at 3192 rpm. The output power loss is about 21% for 1+1 and 32% for 0+2. A definite hit, but if you're looking to save weight, it's a viable way to do it without dropping all the way to 1 CIM (247W at 1287 rpm).
- math error!
Edit3: By assuming a budget of 100A on one side of the drive train, the 2 CIM can deliver 627W at 3365 rpm, the 1+1 542W at 3093 rpm, and a 0+2 can deliver 425W at 2648 rpm. The output power loss is about 14% for 1+1 and 32% for 0+2. A definite hit, but if you're looking to save weight, it's a viable way to do it without dropping all the way to 1 CIM (247W at 1287 rpm).
Quote:
Originally Posted by cbale2000
Also, what are the effects of leaving the gearing on an xCIM + xMiniCIM drive identical between all motors? We've always just geared MiniCIMs the same as CIMs hoping to get a few extra RPM out of the drive. Is this practical or is there some downside I'm not seeing?
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The free speeds are only about 10% different, so gearing the same shouldn't be an issue. It's not like you're going to be able to backdrive the CIM at a higher speed than its bushings were designed for, especially after gearbox losses. If you did want to match them even better, you could just use a pinion with one fewer tooth on the mini-CIM.