KEPCO JQE 150-1.5MVPY-26956 Half Rack - Manual (Page 35)

JQE SPECIAL OPR 081111 4-1
SECTION 4 - CALIBRATION
4.1 GENERAL
It is recommended that both output voltage and output current limit calibrations be performed in
sequence, however it is permissible to do only one if the other is known to be calibrated.
Required test equipment is listed in PAR. 4.2.
E
Onom,
I
Onom,
I
Limit “A” and
I
Limit “B”
are listed in Table 1-1 for each model.
4.2 TEST EQUIPMENT REQUIRED
The following test equipment is required to perform the calibration procedures in this section.
a). Resistive load, variable, with ON/OFF and SHORTING SWITCH and capable of dissi-
pating the full output power of the unit under test.
b). Digital DC voltage monitor (DVM), digital voltmeter, or power supply analyzer.
c). External programming Resistor: value in KOhms: E
Onom
/1mA, tolerance: 0.01%.
d). Precision Current Sensing Resistor (Shunt): 0.1 Ohm, ±0.1%, 50W, 20ppm/°C.
e). AC ripple monitor, sensitivity better than 1 mV. Ballantine Model 302C. or Hewlett Pack-
ard Model 400H or Oscilloscope, vertical sensitivity better than 0.1 mV/cm.
4.3 LAG NETWORK ADJUSTMENT
An a-c stability control in the form of a lag network has been provided in this power supply. This
network has been factory adjusted for maximum amplifier stability when operating into a resis-
tive load. Re-adjustment is indicated if components affecting the a-c characteristics of the ampli-
fier must be replaced, or if the load connected to the power supply contains excessive
capacitance or inductance, causing a-c instability (usually indicated by high-frequency oscilla-
tion as observed with an oscilloscope across the power supply load). In such cases, the lag net-
work should be adjusted so that stable operation is resumed. In extreme cases if adjustment of
the lag network should not prove sufficient, twisted load and error sensing wires or decoupling
capacitance directly across the load may provide a solution to the problem.
1. Connect the power supply to the particular operating load using +V and –V terminals of
TB501 at the rear panel.
2. Use an oscilloscope connected across the load to monitor oscillation.
3. Turn on the JQE special power supply and adjust E
Onom
LAG COMP potentiometer
(accessible through top cover) so that the output is free of oscillation while the unit is oper-
ating in Voltage Mode with the designated load.
4. Turn the JQE special power supply off and disconnect load from +V and –V terminals of
TB501 at the rear panel.
4.4 OVERVOLTAGE PROTECTION (OVP) TEST AND ADJUSTMENT
1. Use the VOLTAGE control at the front panel to set the output voltage to a typical opera-
tional voltage as measured by either the front panel voltmeter or by an external DVM.