The Chadwick-Helmuth Photocell System is used to accurately
measure rotational position for determining phase relationship between elements
of rotating devices such as propellers, rotor blades, fans and shafts at
repetition rates of 0.2 to 830 pulses per second. The Photocell Kit No. 10252
is used with the Chadwick-Helmuth Series 8500 Balancer/Analyzer, 192A Spectrum
Analyzer and Velocimeter Balancers.
The Photocell System measures repetition rates for rotating
devices, without affecting balance, tracking or vibration characteristics of
the rotating device. The retro-reflective tape is attached to the surface of
the rotating device to provide a reflective target for the Optical Probe. The
Optical Probe is attached to a stationary mounting near the target so that the
light transmitted from the Optical Probe is reflected back
each time the rotating target passes. The light that is reflected back to the
Optical Probe is sent to the Photocell Processor for signal processing.
The Photocell System signals are unaffected by external light
such as sunlight, strobe or pulse light, and other ordinary lighting sources.
