| 摘要 |
Current through a motor (18) is sensed at (26) to create a voltage which is amplified at (30). The amplifier (30) is followed by a high pass filter (38) and a low pass filter (46). This recovers commutator pulses from the motor current, rejecting mains ripple and higher frequency noise. Commutator pulses are counted at (58). Other arrangements could be used for injecting pulses into the motor supply, for counting at a remote position. Various techniques are described for controlling the motor in accordance with the result of counting. |
