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PORTABLE TEST SET
for Voltmeters
Model VMTS-.4
400
Volt AC voltage source for verification of HV voltmeter or other types of
AC voltmeters, requiring less than 500 microamps. Battery operated solid
state, safe low power AC test source with built-in indicator light and
automatic switch for HV voltmeter test probe application. Indicates either
open or shorted probes or erratic meter or ground lead operation by means
of combination visible light and meter indication.
HV meter with VM25 or VM50
probe should indicate approximately 2 to 4KV on voltmeter capacitance tap
setting or 200-400V on direct line setting when probe is pressed into test
set probe terminal and ground clip is in contact with test set ground
terminal. Visible light on tester indicates at least 60 volts is present
at test set terminal. If meter does not read 4KV when light is on, erratic
operation is indicated in meter, probe or ground lead.
If test set light does not
come on when test probe is applied, erratic operation is indicated in
either meter or test set. Test set can be checked by disconnecting ground
lead from test set ground terminal. If light goes on when probe terminal
is depressed, test set is generating at least 60 volts.
Test can also be run
without ground lead connected to test set. Meter will indicate
approximately 2KV to 4KV (not recommended for precise calibration, because
of variations possible due to effective load capacitances). Test light
will not light below approximately 60 volts or for loads which have lower
than approximately 600,000 ohms resistive, or over approximately 800
Picofarad capacitive.
Voltage will drop off
proportionately with decrease in load resistance (increase in load
current), but will drop only very little if load is pure (wattless)
capacitance until over the 800 Picofarad level. The supply will then
rapidly saturate, reducing the voltage to a very low value.
See also Model VMT-.5-C for
combination voltmeter verifier and capacitance tap verifier--megohm
leakage indicator to 2000 megohms.
Caution:
test sets are capable of several milliamps which can cause slight shocks.
Model VMT-.5 Voltmeter
Tester, Megmeter®
For portable hotstick
operation, this is a combination source of 400V AC and 500V DC voltmeter
tester-megohm leakage indicator in one small flashlight size unit.
Supplies 400V AC to and VM25 & VM50 capacitance tap probes plus 500V
DC megohm indicator which will indicate contamination or leakage on the
capacitance tap or any insulation, even in the presence of an AC voltage
as high as 15KV AC with an ungrounded source. Unit will indicate in the
range of from over 2,000 megohms down to 20 megohms and less by means of a
flashing neon lamp. Critical leakage resistance values in capacitance taps
and most HV insulation are in the order of 20 megohms to over 2,000
megohms, and this unit is designed for this range as well as short
circuits. 400V AC test section is similar to Portable Tester VMTS-.4.
Model VMT-.5C HV Adapter
for Megmeter®
The
hotstick adapted VMT-.5-C is available as a combination 500V DC megohm
indicator 400V AC tester for voltmeters, capable of withstanding up to
15KV AC on capacitance taps or direct AC lines and reading DC leakage
resistance even on the energized capacitance tap or ungrounded high
voltage AC line.
Caution:
With 15KV isolation limiter test set output current is limited to approx
50 microamps at tip but is capable of several milliamps at 400V AC VM test
point which can cause slight shocks.
Caution:
Safety rules apply when using in the possible presence of high voltage.
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