7
Connection to the Load
The load should be connected to the positive (red) and negative (black) output terminals. Both
are fully floating and either can be connected to ground.
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 (
) is 300VDC.
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.
Ventilation
The power supply is very efficient but nevertheless can generate significant heat at full power.
The supply relies on convection cooling only and it is therefore important that ventilation is never
restricted if performance and safety are to be maintained.
Audible Noise
When the DC output power is reduced to a few Watts at low voltages and/or low current levels the
switched
−
mode stage controller starts to ‘skip’ pulses. This has the effect of bringing the
switching frequency into the audio range and occasionally some audible noise can be heard
because of the electro
−
acoustic action of the transformer. This is entirely normal and does not
affect performance in any way.
