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| Re: Canarsie CBTC (98944) | |||
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Tue Jun 14 21:57:22 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Tue Jun 14 21:13:06 2005. Control of the torque and speed of an induction motor doesn't require tach feedback. It can be done easily through current sensing. Vector (position) control is tougher to do this way (although reasonably practical if you have an accurate model of the motor's characteristics).I do remember the R142 description on Bombardier's website mentioned closed loop control for the AC traction motors. Tach outputs are pretty cheap, so it seems the logical way to go. Then again, the TA did have the vendors change the propulsion package during the R142 acceptance tests after some trains were caught speeding. I wonder :=) One problem with using only current feedback is that you can no longer account for variability between motors. |
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