Four electronic operate from
three-phase supplies between 400V and 500V ac, and provide adjustable
outputs from 24 to 28V dc with ratings of 5, 20, 30 and 40A. All models
have full-load and no-load regulation of better than 2% and all can
sustain loads substantially in excess of their nominal rating for up to
one minute. This avoids having to specify larger (and hence more costly)
power supplies for applications involving high short-term start-up loads.
The power supplies offer a ‘hiccup’ mode, which is automatically engaged
when a short circuit or overload fault is detected, the output voltage
being initially reduced to zero. The output then pulses briefly at
intervals to determine whether the fault condition has cleared. If this
is the case, normal operation is automatically resumed.