Operator`s manual

Rev. 1/99 Vicor 800-735-6200 Westcor Division 408-522-5280 Applications Engineering 978-749-3524 or -3525 Pg. 11
3 Phase MegaPAC Owner’s Manual
Enable/Disable and General Shutdown (GSD)
The Enable/Disable control lines allow ConverterPAC outputs to be sequenced either on or off. For DualPACs,
both outputs are sequenced. In parallel arrays, only the driver ConverterPAC needs to be sequenced. The GSD con-
trol line on J10-5 allows simultaneous shutdown of all ConverterPAC outputs. An internal jumper selects polarity,
either active-high or active-low. Another jumper selects a pull-up or pull-down source for the HCMOS control
inputs.
For standard 3 Phase MegaPACs, the Enable/Disable controls are configured as active-low with internal pull-up;
outputs are enabled when these pins are open-circuited or allowed to exceed 4.5V with respect to Signal Ground.
Outputs are disabled when the Enable/Disable control lines are pulled low to less than 0.7V. The GSD control line
is configured to be active-low with internal pull-up; all outputs are simultaneously inhibited when the GSD control
line is pulled low to less than 0.7V. All outputs are enabled when GSD is open circuited or allowed to exceed 4.5V.
Do not apply more than 5V to these inputs at any time. The E/D and GSD circuits will sink up to 0.6 mA. If dri-
ven from an electromechanical switch or relay, a small capacitor should be connected between the control line and
Signal Ground to eliminate latch-up due to the effects of switch bounce (1µF, typical).
AC Power OK (J10-18)
This signal on J10-18 provides a status indication of the AC input power (see Figure 13). It is active high, TTL
compatible and capable of sourcing 10 mA maximum. This signal switches to a TTL “1” when the high voltage
bus exceeds low-line condition during turn-on, and switches to a TTL “0” 3 ms (minimum) before loss of output
regulation due to the loss of input AC power. This signal can be used to warn external control circuits of an
impending loss of power.
Figure 12. Enable/Disable and General Shutdown
Figure 13. AC OK/Power Fail