2
Description
Description
The test set pictured in Figures 1 and 2 show the Type PTS-
4 Portable Test Set and a typical test set-up.
Rating
Input—120 Volts, 50 or 60 Hz, 15 Amps Maximum. Output—
0 to 120 Volts, 15 Amps Maximum. Maximum continuous
current on high scale 1.0 Amp. Maximum continuous current
on low scale 0.75 Amp. DC output for actuator test—0 to 22
Volts Open Circuit.
Calibration
Using an R.M.S. reading ammeter and sine wave current, the
test set ammeter is factory calibrated on low scale at 0.50
a 1% and on high scale at 3.00 a 1%. The
electronic stop clock is factory calibrated at 300 s
5 seconds.
Construction Details
The test set is basically a variable voltage AC supply, with built
in reactors to smooth the current against the trip device non-
linear impedance. The output of the AC supply is controlled
by a system of relays to start and stop the current. An
electronic stop-clock is used to time the duration of current
flow, and an ammeter to measure its magnitude. The relays
are operated by the output of the trip device under test to stop
the current. A small DC voltage source is built into the tester
for use in testing the magnetic tripping actuator of the circuit
breakers. The output of this small supply is monitored by a
built-in digital voltmeter.
