KEPCO, INC.
131-38 SANFORD AVENUE
FLUSHING, NY. 11355 U.S.A.
TEL (718) 461-7000
FAX (718) 767-1102
http://www.kepcopower.com
email: [email protected]
020316
228-1768
5
3.5. COOLING.
The components in the ATE-DMG
power supply rely on forced air cooling.
CAUTION: SIDE
PANEL AND REAR PANEL OPENINGS AND THE TOP
OF THE CASE MUST BE KEPT CLEAR FROM ALL
OBSTRUCTIONS TO ENSURE AIR CIRCULATION.
Peri-
odic cleaning of the interior of the power supply is recom-
mended. When the ATE-DMG is rack-mounted or installed
into confined spaces, care must be taken that the ambient
temperature (the temperature immediately surrounding the
power supply) does not rise above 50°C (~122°F). Derate
power by 10% if ambient temperature exceeds 55°C
(~131°F).
IV — OPERATION
Turn the unit on using the front panel a-c
POWER
ON/OFF
switch/circuit breaker (see CAUTION, PAR. 4.3).
The ATE-DMG power supply is delivered for “slow mode”
operation (see PAR. 1.2). Refer to full Operator Manual
(see PAR. 1.1) for converting the ATE-DMG power supply
to “fast mode” operation.
4.1. OVERVOLTAGE CROWBAR SETUP AND
CHECK.
The overvoltage crowbar circuit protects the load
from momentary or long-term overvoltages. The crowbar
SCR conducts across the power supply output, and the a-c
power switch/circuit breaker is tripped if overvoltages
occur. The front panel
LEVEL
control determines the
threshold between the actual operating voltage of the
power supply and the level at which the crowbar circuit will
be activated. The
LEVEL
control can be set from 3 volts to
110% of the rated output voltage. The
LEVEL
control may
be adjusted very close to the operating voltage (minimum
threshold = 2% of rated output voltage or 0.5 volt, which-
ever is greater). The operation of the crowbar circuit can be
checked as follows without actually triggering the crowbar.
All operating controls are accessible at the front panel (see
Figure 1).
1. Without connecting the load to the power supply turn
Crowbar LEVEL control fully clockwise.
2. Turn a-c
POWER
switch/circuit breaker on. Press
V SET
key, then use the keypad to enter the desired
value at which the crowbar must trigger (NOT the actual
operating voltage), then press
ENTER
.
3. Depress the
DISABLE
button (and keep it depressed)
white turning the
LEVEL
control counterclockwise, until
the
CROWBAR
indicator energizes (simulated crowbar
action).
4. With the
DISABLE
button still depressed, press
V SET
key, then use the keypad to enter the actual operating
voltage and press
ENTER
key. Release the
DISABLE
button.
NOTE: This last adjustment established the threshold, i.e.,
the difference voltage between the output voltage
and the voltage at which the power supply will
crowbar. For minimum false triggering use the larg-
est threshold your load can tolerate.
5. To check the adjusted crowbar trigger level, depress
DISARM
push button. Press
V SET
key, then use the
keypad to enter the voltage trip point, minus 1%, then
press
ENTER
.
6. Depress the
key and note the voltage at which the
CROWBAR
indicator lamp energizes. Correct
LEVEL
adjustment as described above if necessary. Use
V SET
to reduce power supply output voltage to its
operating value.
NOTE: Readjustment of the
LEVEL
control may be
required after load and power supply have reached
thermal equilibrium.
If an exact crowbar point at a remote load must be
established, remote error sensing, as described in
PAR. 3.4.3 must be used.
4.2. LOCAL MODE (KEYPAD) OPERATION.
The
front panel keypad is comprised of 24 key, 13 dedicated to
command functions, 5 dedicated to data functions, and 6
keys that have both command and data functions When
the power supply is in command entry status the command
functions are effective; when the power supply is in data
entry status the data functions are effective.
4.2.1. COMMAND ENTRY STATUS.
Indicated by a blink-
ing colon (:) on the bottom line of the LCD. The power sup-
ply is waiting for a command to be entered; data will not be
accepted (accompanied by brief audible buzz). The LCD
indicates the actual voltage and current at the output termi-
nals. When the output is disabled (LCD bottom line reads
Output OFF
), the power supply is in Command entry sta-
tus even though the blinking colon is not visible.
NOTE: Blinking colon is indicated by in this manual.
4.2.2. DATA ENTRY STATUS.
Entered automatically
when data entry required. Indicated by blinking equal sign
(=) on bottom line of LCD; the power supply is waiting for
data to be entered. A command will not be accepted
(accompanied by brief audible buzz). Enter new value (the
