Patent ID: 7185528
Filing Date: 2007-03-06
Classification: F04B,F04D,G05D,H02P

Abstract:
1. A gas monitoring apparatus, comprising: a sensor testing gas samples for contaminants; a pump communicating with the sensor, the pump providing the gas samples to the sensor; a motor driving the pump; a motor driver providing drive signals to the motor to control operation of the motor; and a sampling unit sampling motor back electromagnetic force (EMF) during intervals between the drive signals, the motor driver adjusting the drive signals based on the back EMF sampled, wherein the motor driver comprises a controller that, during sampling of the back EMF, at least one of delays the onset of at least one drive pulse of the drive signals, increases an interval between two adjacent drive pulses, reduces a width of at least one of the drive pulses, and eliminates at least one of the drive signals.