Operation Manual / 4 Product description / A200-L7 Troubleshooting / 7.5 Speed measurement system© Copyright 2018 ABB. All rights reserved. HZTL4036_EN Revision M August 20187.5 Speed measurement systemPossible causes RemedyNo signal orpoor signalamplitudepresentAssembly fault The screw plug for the sensor is fitted with a gasket.This gasket must be removed when the speed sensor is as-sembled. If the gasket has been inadvertently fitted, the distanceof the sensor tip to the sealing disc giving the signal is increased.This reduces the voltage amplitude of the speed signal which canlead to problems with the evaluation electronics.This problem will be remedied by removing the gasket.Sensor defective Contact ABB Turbocharging Service StationMeasuredspeed toohighContamination ofthe sensor tipAs the sensor tip is magnetic, it can attract material particles.This reduces the distance to the auxiliary bearing, which can leadto amplification of the noise component and therefore to falsetriggering.Dismantle the sensor, clean the sensor tip, and fit the sensorback on with the specified tightening torque.Measuredspeed toolow- - Contact ABB Turbocharging Service StationOthercauses ofmalfunction- - If none of the measures described above remedy the malfunc-tion, it is recommended to have the speed measurement systemchecked by an ABB Turbocharging Service Station.Table 26: Malfunctions of the speed measurement systemPage 49 / 108
