Sense Miswiring Trip; Series Or Parallel Connection With Other Outputs; Over-Voltage Protection - TTI QL Serie Manual De Instrucciones

Sense Miswiring Trip

The output will be tripped off if the voltage between an output terminal and its corresponding sense
terminal exceeds approximately 1V; this will happen if the sense wires are wired at the load to the
wrong output or if an attempt is made to draw power from the sense wires.
If the sense terminals are miswired in this way the display shows the message
the output is turned off. Pressing ESCAPE at this point removes the message and the display now
shows the preset voltage and current limit. When the cause of the trip has been corrected the output
can be turned on again.

Series or Parallel Connection with Other Outputs

The outputs of the power supply are fully floating and may be used in series with other power supply
units to generate high DC voltages up to 300V DC.
The maximum permissible voltage between any terminal and earth ground (
WARNING! Such voltages are exceedingly hazardous and great care should be taken to shield the
output terminals for such use. On no account should the output terminals be touched when the unit is
switched on under such use. All connections to the terminals must be made with the power switched
off on all units.
It should be noted that the unit can only source current and cannot sink it, thus units cannot be series
connected in anti-phase.
The unit can be connected in parallel with others to produce higher currents. Where several units are
connected in parallel, the output voltage will be equal to that of the unit with the highest output
voltage setting until the current drawn exceeds its current limit setting, upon which the output will fall
to that of the next highest setting, and so on. In constant current mode, units can be connected in
parallel to provide a current equal to the sum of the current limit settings.
Note that the output terminals are rated at 15A maximum; if several outputs are operated in parallel
to source higher currents than this the junction should be made at a separate point, not one of the
terminals.

Over-Voltage Protection

Over-Voltage Protection (OVP) can be set from 1·0V to 40V (QL355), 1·0V to 60V (QL564). If the
output voltage exceeds the set OVP the output is immediately shut down (typically within 100µs),
thus avoiding damage to the circuit under test. The OVP circuit will protect against accidental
excessive voltage settings from the front panel or via the remote control interfaces, external voltages
impressed across the output terminals, or a failure in the control circuitry of the instrument itself.
To set OVP press SHIFT, OVP; the 100mV step JOG indicator will start flashing and the jog rotary
control can be used to increment/decrement the OVP setting in 100mV steps. Press OK to confirm
the new setting; to exit without entering a new value press ESCAPE. The factory default setting is
40·0V (QL355), 62·0V (QL564).
If the OVP is tripped the display shows the message
Pressing ESCAPE at this point removes the message and the display now shows the preset voltage
and current limit. When the cause of the OVP has been removed (or the OVP limit changed) the
output can be turned on again.
Note that the OVP setting is not changed when the range is changed (e.g. an OVP setting of 38V
remains valid on the 15V range); it is left to the user to independently change the OVP setting if
required.
Note also that it is possible and valid to set OVP below the set voltage. If the supply is in constant
current mode the output voltage will be below the set voltage; OVP could be set such that is was
above the actual output voltage but below the set voltage. This could be used to trip the output
under a fault condition which caused the load impedance to increase and the actual output voltage to
therefore rise above the OVP point.
and the output is turned off.
OUP triP
and
SENSE triP
) is 300VDC.
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