- 9 -
4000 4 334_EN- 02/09
ENGLISH
4 - WORKING PRINCIPLE
4-1 WORKING LIMITS
Temperature shutdowns can appear in case of fan defect.
- DC current output falls to 0 Volt and 0 Amp (temperature control on the heat sinks)
- The power supply completely switches off (internal shutdown by transformer).
4-2 REMINDER ON RECTANGULAR CHARACTERISTICS
A power supply that can work with constant voltage or constant current is said rectangular characteristics (D. 2).
The transition from «constant voltage»operation towards «constant current»operation is automatic according to the
adjustments of Vs and Is and to the load applied to the output.
If load resistance RL is superior to the Vs/Is ratio, the power supply works in constant voltage for the output voltage
value chosen and with a current limit to Is.
If RL varies from infinite to Vs/Is, I can vary from 0 to Is (example I1) and output voltage is constant.
Thus, to make the power supply works in constant voltage, the output current should be inferior to the selected limit
current.
In the contrary case, the power supply changes its way of operation and passes in constant current.
If load resistance RL is inferior to Vs/Is ratio, the power supply works in constant current, for a selected current value and
with a voltage limit to Vs.
If RL varies from 0 to Vs/Is, V can vary from 0 to Vs and Is = constant (example V1). Thus, to make the power supply
works in constant current, the output voltage adjustment must be at the maximum of the specified values.
Caution
, when the adjustments of the output limit voltage and current are such as the load resistance is equal to
the ratio Vs/Is, this can lead to an instability of operation.
5 - WORKING
5-1 MOUNTING AND PLACING OF THE INSTRUMENT
For an optimal operation, the power supply must stand on its 4 rubber thrusts. The
back panel must be widely cleared not to block the air flow of the fan.
Unfold the main power cord of its housing and connect it to a 230 V AC socket, your
instrument is ready to work.
5-2
USE
Push on the
«I»
of the ON/OFF switch [
1
], the indicators light up, your power supply
is working.
The voltage value and current value available on the DC output [
4
] are adjustable
thanks to the knobs [
5
] [
6
] [
7
] and displayed on [
2
] and [
3
].
Constant voltage use
Adjust the current to max or to a max value desired with [
5
].
Adjust the voltage to the desired value with [
6
] [
7
] on the display [
2
].
Connect the load on the sockets [
4
].
Control the voltage regulation by the enlightened green LED and the current consumed by the display [
3
].
Constant current use
Adjust the voltage to max or the max desired value by [
6
] and [
7
].
Do a short-circuit on the sockets [
4
] and adjust the current to desired value with [
5
] on display [
3
].
Take off the short-circuit and connect the load on the sockets [
4
].
Control the current regulation by the enlightened red LED and its value on the display [
3
].
5-3 Precautions
Always adjust the power supply before connecting the load.
Connect the load with sufficient diameter (1mm²) insulated cord.
Disconnect the load before switching off the ALR3003.
Avoid dust for the storage of the instrument.
A temperature control circuit controls the fan, it works only when necessary.
6 - MAINTENANCE
No particular maintenance is required for this instrument. Avoid dust, humidity, shocks : your instrument will
be grateful to you for that. For cleaning, please use a smooth duster :
If indicator does not light up when plugging, check :
- if ON/OFF switch is activated
- the connection to the main input voltage
- Main voltage presence
RL=Vs/Is
RL>Vs/Is
V
Vs
V1
D.2
RL<Vs/Is
I1
Is
I
