Wayne Kerr AP10030, Руководство пользователя и обслуживания

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30 Wayne Kerr AP 1kW Power Supplies • Issue 2
h) Setting The Output Voltage And Current Of Series Combination
The output voltage of this combination is set by controlling the master unit output
voltage. This can be done by the front panel potentiometer or by remote programming.
The total output voltage is a multiple of the master unit output voltage. The multiplying
factor is determined by the choice of resistor dividers X and Y described previously. The
current limit is determined by the master unit setting. The current limit settings of the
slaves should be set above the maximum load current required. This avoids interference
with the master.
6.5. Line Impedance Test
WARNING - This test necessitates operating the unit with covers removed and should
only be performed by qualified personnel. Hazardous voltages are present within the unit
and can remain for up to 15 minutes after removing the input power.
Low Mains Potential
This a.c. line impedance test should be performed if the unit is operating near to the
minimum rated input voltage. With normal line impedances, the unit should work
correctly down to the minimum a.c. input. If the a.c. line impedance is high the unit may
be incapable of supplying full output power or may overheat when delivering full output
power. High a.c. line impedance can be due to poor mains wiring, long extension leads or
poor connections somewhere in the system. Measuring the a.c. line voltage is an
insufficient test due to the peak-clipping effect of the power supply.
Procedure
WARNING - Hazardous voltages are involved in this test and all safety precautions
should be taken.
To perform the a.c. line impedance test, proceed as follows:
a) Switch off instrument, disconnect from the mains and wait 15 minutes before
removing top cover as described in section 5.1.
b) Connect a d.c. voltmeter, capable of reading up to 500V, across the two series
connected large line capacitors (C401, red wire and C402, black wire) and monitor
the voltage.
c) Connect a load capable of taking the maximum output current and power of the unit
(i.e. on AP6050, say 50A at 20V).
d) Connect the unit to the mains and switch on.
e) Switch ‘output enable’ to the ‘ON’ position and adjust for the required output
voltage (i.e. 20V on AP6050). Turn current limit fully clockwise.
f) Adjust the load to draw maximum specified output from the supply, checking the
unit is still in CV mode.
g) Observe the reading on the voltmeter. The mean d.c. voltage across the line
capacitors should be greater than 270V. Readings may fluctuate due to the presence
of a 100Hz ripple of several volts magnitude across the capacitors. If the voltage
measured is less than 270V either the mains supply is too low or the impedance is
too high.