The tuned voltmeter
TVM 1058* is specifically designed for use with the LCI unit to detect
58 Hz voltage under very noisy conditions. In some instances,
the residual 50 Hz or harmonic voltages on the earthing/grounding system
or induced in the test circuits may be many times the 58 Hz test signal
level. The TVM is able to filter out unwanted frequencies.
This means very low levels of test voltage may be identified anywhere
on the site under test, even where the background signal level is high.
The TVM has a high
input impedance to ensure accurate reading of prospective touch, step
and transferred voltages. It also has a switchable low input impedance
(1 kO) to simulate a person’s body impedance.
The TVM can also be
used with a diesel genset when it is impractical to use the LCI unit.
*For 60 Hz systems
TVM 1052 is available, and is tuned to 52 Hz ± 1 Hz
Finalist - IEE
Innovation Awards 2005