Tacho-Generator Replacement

Tacho-generators were fitted to many older gas generators such as RR Avon and Olympus engines to measure shaft speed. These devices are three phase generators that produce a low-frequency, low voltage output. This signal can be difficult to read using digital counter modules for the following reasons:

• The low frequency causes resolution problems and inaccuracy in speed measurements.
• The amplitude is low at low speed and might not reach the trigger level of the module. This is particularly critical for measurement at turbine barring speeds.
• The signal is extremely susceptible to electromagnetic interference, causing a fluctuating speed reading.
• The connectors of these devices have proved extremely unreliable and the electrical connections break down in the harsh industrial environment of a Power Station.

We produce a replacement device that utilises a phonic wheel and magnetic pick-up (MPU). This picks up the same drive as the existing tacho-gen, but the phonic wheel and MPU produces a higher frequency and amplitude AC output.