Thread: Batteries
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Old October 28th 16, 12:23 AM posted to sci.electronics.repair
Michael A. Terrell Michael A. Terrell is offline
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Default Batteries

wrote:
On Monday, October 10, 2016 at 9:55:49 AM UTC-4, Chris Jones wrote:

That could happen if the motor controller is very crude, but a good
motor controller would incorporate current limiting, and the current
limit should be set below the fuse blowing current.


Bluntly, I would be surprised if the motor controller is anything more than a primitive SCR speed control and a fuse as a last-resort. These go-buggies are just short of a racket, with a very few genuine exceptions. And a brush-type DC motor will pull current even when not turning right down to a dead-short when the voltage drops below what is necessary to turn the motor against the load - and THAT is what blows the fuse.




I would be surprised to see an SCR that worked in a DC circuit,
unless it was a GTO type. All of the controllers that I've had on the
bench were PWM, with sets of PowerFETs for each motor. Each motor was
driven by a high power H bridge. All of the controllers that I've had on
the bench were built with International Rectifier components.


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