KEPCO EL Series Quick Start Guide

QUICK START GUIDE

KEPCO

An ISO 9001 Company.

SINGLE- AND DUAL-CHANNEL

ELECTRONIC LOAD

I — INTRODUCTION

SCOPE OF MANUAL. This Quick Start Guide covers

the installation and operation of the Kepco Series EL Elec­tronic Loads. Full specifications are listed in the applicable
Operator’s Manual that can be downloaded from the Kepco
web site:

• www.kepcopower.com/support/opmanls.htm#el

OPTIONS. D option (suffix D added to model number) models are dual-channel units comprised of two completely independent electronic loads in a single chassis. The con­trols, indicators and connections are identical to the single unit described herein, except they are labeled channel A or B; the single POWER switch applies to both channels.

The G option (suffix G added to model number) includes
the GPIB interface. For single units the GPIB interface is in
addition to the standard RS 232 and USB interfaces. For
dual units the GPIB interface replaces the standard RS
232 and USB interfaces.

The E Option (suffix E added to model number) includes
the Ethernet (LAN) interface in addition to the standard RS
232 and USB interfaces.

DESCRIPTION. The Kepco Series EL are modular, air­cooled, electronic loads. Typically these loads are used to test DC power sources, such as batteries, power supplies, generators, chargers, fuel cells, etc.

The Series EL dissipates power from the Unit Under Test
(UUT). The UUT is the source of the electrical energy
tested by the Series EL.

II — SAFETY.

Exercise care in making all connections between the Series
EL and the UUT.
.

WARNINGS

1. Very high voltages may be present when using this
electronic load. EXERCISE PROPER PRECAUTIONS!

Series EL

2. High currents may be present when using an electronic
load. EXERCISE PROPER PRECAUTIONS!

3. Loose connections or insufficiently sized conductors
can become very hot and cause burns. Loose test con­nections between the UUT and the Series EL can also
lead to load instability, erratic operation and equipment
damage.

4. The negative load terminal of this electronic load is elec­trically isolated (d-c) from the control interfaces, how­ever, capacitance between these connections can lead
to coupling of fast transients. Therefore, when operating
this load with external control connections, the user
should ensure there is no transient coupling between
these points to avoid serious damage to the connected
instruments and/or this load.

III — INSTALLATION

UNPACKING. Upon receipt, the Series EL and its

accompanying components should be carefully unpacked
and removed from the shipping container. Separate all
parts from the packing material and inspect for any external
damage. Record packing methods for future re-shipment.

If any dented, broken or loose parts are seen, do not use
the equipment. Notify the shipping company immediately
and follow their instructions for remedial action.

OPERATING VOLTAGE SELECTION. The Series EL is delivered configured for operation from 120V a-c (±10%), 50/60 Hz. If the Series EL is to be operated from a 240V a­c (±10%), 50/60 Hz power source, or the input power range needs to be changed from a previous selection, Refer to the Series EL Operator manual.

CAUTION: Series EL do not automatically switch 120V/
240V line voltage; applying 240V to a unit configured
for 120V will damage the Series EL.

MOUNTING. Mount the Series EL in a standard 19-inch wide rack or use on a bench. Allow sufficient room for venti­lation at front and rear.

WARNING: The unit is very heavy (80 to 90 pounds).
Exercise care when lifting, mounting or otherwise han-

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dling this product. It is recommended that two or
more persons handle the unit.

CAUTION: Refer to the Operator’s manual for optional
slide installation. Failure to use slide and screws
specified will damage the unit and void the warranty.

CONNECTIONS. See Figure 3 for typical test connec­tions. The Series EL is capable of drawing very high cur­rents. Connections between the UUT and the Series EL must be properly sized to carry the maximum current. Additionally, it is extremely important to ensure all connec­tions are tight and corrosion free. See Section II, Safety Warnings. Use low resistance hardware supplied with the unit for connections to ± LOAD terminals. Regular inspec­tion of ±LOAD connection tightness is important.

Connect the Series EL to the UUT using cabling
appropriate for the current expected during testing.

CAUTION: Ensure polarity is correct - reversed
polarity will cause immediate and significant damage
to the Series EL and/or the UUT. Contact Kepco if

assistance is needed in selecting the appropriate wire
size, length and physical configuration. Ensure all
connectors are suitable for the current and voltage
expected and that connections are tight. Connections
should be re-checked to ensure continued low-resistance
connections on a regular basis. CAUTION: When

connecting the Series EL to the UUT be very careful
not to accidentally short the UUT output while
connecting the wiring. Best practice is to make the
connection to the UUT Positive (+) output connector
the last connection.

Refer to the EL Operator manual for connections required
for remote control.

IV — OPERATION

Operation is either from the front panel (local) or via com­puter control (remote). For remote operation, refer to the
EL Operator manual.

CONTROLS AND INDICATORS. Figure 2 shows the location of front panel components described in Table 1.

STARTUP.

1. After all connections are completed, turn on system by
setting ON/OFF switch to ON.

4. When ready, the LOAD switch-indicator lights green.
The VOLTS display shows the voltage of the source
under test. AMPS and KW displays indicate zero.

TABLE 1. FRONT PANEL FUNCTIONS

SEE

FIG. 1

COMPONENT FUNCTION

1 AMPS display Displays the load test current in Amps

On (solid) indicates Constant Resistance

2 CR indicator

3 CI indicator

4CV indicator

5CP indicator

Power ON/OFF

6

7 LAN indicator

8 LOCAL indicator On indicates Local mode is active.

9

10

11 K W dis pla y

12 VOLTS display

switch

CONTROL

rotary control/

pushbutton switch

LOAD

pushbutton

switch/indicator

Mode; factory default set to 1000 Ohms. On
(blinking) indicates Constant Conductance
Mode; factory default set to 1mS (0.001
siemens, I/E).

On to indicate Constant Current Mode
(factory default setpoint: 0A. After use, the
last used setpoint is retained).

On to indicate Constant Voltage Mode
(factory default setpoint: maximum load
voltage).

On to indicate Constant Power Mode (factory
default setpoint: 0 kilowatts).

Rocker switch: press top half to turn power
on, bottom half to turn power off.

On indicates optional LAN connection is
active.

When LOCAL is active, three functions are
available as follows:
a. Select Mode: Press, hold (at least 3
seconds) and rotate knob to select mode
indicated by the CI, CR, CV and CP
indicators (see Table 2).
b. Set Value: Rotate knob to adjust the level
of the controlled parameter: current, voltage,
resistance, conductance or power (see Table

3). Rotate clockwise to increase,
counterclockwise to decrease. Settings are
stored and will be available at next power-up.
c. Select Digit: Momentarily press knob to
select one digit (blinks). Convenience
function allows adjustment of one digit at a
time.

Indicator lights to show load status: green
(ready to operate), amber (load is engaged)
or blinking red (fault condition exists). Press
switch to engage/disengage load or clear
fault indication.

Displays the power (Amps x Volts) being
dissipated by the load in kilowatts. Also
momentarily indicates resistance (in Ohms)
or conductance (in Siemens) setting.

Displays test voltage from UUT applied to the
load in Volts.

SET SETPOINT ADJUSTMENT RESOLUTION.

2. After warming up for about 15 seconds, the unit begins
the power-up self-test.

1. Momentarily press the CONTROL knob a number of
times to select the digit representing the resolution
needed for adjustment during test (selected digit

3. Set the desired Mode (see steps 1 and 2 of “Changing

blinks).

Settings.” on page 4).

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2. For example, if 1A per click of adjustment is desired,
select the most significant digit (MSD), which yields 1
Amp per click. If finer resolution is desired, select a less
significant digit such as 100mA or 10mA per click (see
Figure 1). NOTE: Leading zeroes are suppressed.
Therefore from 0A to 9A, the MSD shows units of Amps.
From 10A to 99A the MSD shows 10A per digit. Clicks
can be set to a maximum of 10A/click. The adjustment
is continuously variable up to the maximum value for
the selected mode. Choosing a less significant digit
increases the number of turns x 10 per digit.

FIGURE 1. ADJUSTING RESOLUTION

MODE

INDICATOR

Only CI on

(solid)

Only CR on

(solid

Only CR on

(blinking)

Only CV on

(solid)

Only CP on

(solid)

CI, CR, CV and

CP all blinking

CI, CR, CV and

CP all off

FIGURE 2. FRONT PANEL CONTROLS AND INDICATORS

TABLE 2. MODE SELECTION

MODE SELECTED

CI (Constant Current) mode.

CR (Resistance) mode.

CS (Conductance) mode.

CV (Voltage) mode.

CP (Constant Power) mode.

Short mode (lowest resistance possible), maximum
current. USE CAUTION prior to setting,

Modes off: Load will not engage, no setpoints are
active and load will not conduct current.

MODE

INDICATOR

Only CI on

(solid)

Only CR on

(solid

Only CR on

(blinking)

Only CV on

(solid)

Only CP on

(solid)

CI, CR, CV and

CP all blinking

CI, CR, CV and

CP all off

TABLE 3. LOCAL ADJUSTMENTS

SETPOINT ADJUSTMENT

when LOAD switch shows green

CONTROL sets constant current level in Amperes
as viewed on AMPS display.

CONTROL sets resistance in Ohms as viewed on
KW display.

CONTROL sets conductance in Siemens (I/E, I in
Amps, E in Volts) as viewed on KW display.

CONTROL sets voltage in Volts as viewed on
VOLTS display.

CONTROL sets constant power level in kilowatts as
viewed on KW display.

Short mode; no adjustment. USE CAUTION prior to
setting.

Modes off; no adjustment. Pressing LOAD switch
causes indicator to blink green, then CONTROL
used to view model, serial number, IP information,
etc.

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RUN TEST. To run a test proceed as follows: If the test is run immediately after unpacking and installing the unit without changing the factory default settings, the mode will be CI mode and setpoint at 0 Amperes). To change the settings before running the test, see CHANGING SET­TINGS below. Once the settings are changed, the new settings will be saved when the unit is turned off, and will be restored when the unit is powered up.

1. Set desired mode (see steps 1 and 2 of “Changing
Settings.” on page 4) and resolution (see “Set Setpoint
Adjustment Resolution.” on page 2).

2. Press the green LOAD button to engage the load. The
LOAD indicator changes from green to amber, indicat­ing the load is engaged with the source under test.

3. The load will respond according to the default settings
or to your prior memorized settings

4. If the load has not been previously set up, then it will
be in the CI mode and will engage at 0 Amperes

5. Turn the multi-turn CONTROL knob to the desired cur­rent.

CHANGING SETTINGS. Prior to engaging the load you may preset the load to a given set of conditions. After presetting conditions, you may need to fine tune the actual values depending on your test conditions. (see EL Operator manual for details.)

1. Depress and hold the CONTROL knob until the Green
LOAD button turns off (~ 3 seconds), indicating you
may rotate the knob and select the desired mode.

2. While holding the knob in, rotate it until the desired
mode is selected as indicated in Table 2, then release
the knob. The mode indicators will illuminate in the
order shown in Table 1.

3. To adjust the value (setpoint) for the selected mode,
rotate the CONTROL knob (without depressing); see
Table 3. To make the adjustment easier adjust resolu­tion as desired (see “Set Setpoint Adjustment Resolu­tion.” on page 2).

4. When satisfied with the setting, press the green LOAD
button to begin (engage) the test. The LOAD indicator
changes from green to amber to show the load is
engaged.

6. At the completion of the test, press LOAD switch to
disengage the load; LOAD indicator changes from
amber to green.

5. The selected mode setpoint value may be changed
during the test by rotating the CONTROL knob (see
Table 3).

6. At the completion of the test, press LOAD switch to
disengage the load; LOAD indicator changes from
amber to green.

FIGURE 3. TEST SETUP, TYPICAL

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