Based on both the Model 4040 Frequency Instrument and the Model 4078 AC Strain Gage Instrument, the Model 4K/HP is a two-channel instrument for accurate measurement of TORQUE, RPM, and HORSEPOWER.
Like the analog input of the 4078, the 4K/HP's torque input channel is of phase-sensitive carrier-amplifier design, and accepts a force-measurement signal from a conventional strain gage transducer with a 4-arm bridge of nominal 350 Ω or higher, and a full-scale range of 0.75, 1.50, or 3.00 mV/V.
Like the analog input of the 4040, the 4K/HP's frequency (or RPM) input channel accepts a pulse signal from a tachometer pickup, turbine flowmeter, transistor or logic-circuit driver, "zero-velocity" (true digital output) sensor, or similar frequency-generating transducer.
Reported by a separate data channel, a "live" horsepower value is continuously calculated from the "tared" readings of these two inputs (under the 4K/HP's "standard configuration," the tare offset for the frequency channel is always zero).
