Specifications

12
1-800-927-9474
20-11
Three Phase MegaPAC Interface Connections (cont)
For standard Three Phase MegaPACs, the Enable/Disable controls are configured as active-high
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. If driven 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 (1 µF, typical).
AC Power OK (J10-18)
This signal on J10-18 provides a status of the AC input power. It is active high, TTL compatible
and capable of sinking 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 (typical)
before loss of output regulation due to the loss of input AC power. This signal may be used to
warn external control circuits of an impending loss of power.
AC Power Fail (J10-19)
J10-19 is the inverse of AC Power OK, and goes to a TTL “1” when the input AC power is not
OK. It is capable of sinking 10 mA maximum. The fan out is 20.
Phase Fail (Input Overcurrent) (J10-14)
J10-14 is a TTL level active-high signal, that is asserted when the peak input current reaches
30A due to the loss of an input phase, or severe line imbalance. This occurs when one input
phase is lost with approximately 1400W output loading. Maximum current that can be sourced
is 10 mA.
Analog Temperature (J10-4)
J10-4 provides an analog DC voltage between 0V and 10V, representing an inlet air temperature
of 0˚C to 100˚C, respectively. The temperature is monitored close to the fan.
Overtemperature Warning (J10-3)
J10-3 asserts a TTL level “1” if the inlet air temperature exceeds the following factory set
levels. For standard units, the warning trip point is between 65˚C to 76˚C. The recovery point is
1˚C lower than the actual trip point.
Figure 14.
AC Power OK,
AC Power Fail and
Phase Fail
2.49K
Signal Ground
2.49K
AC Power Fail
AC Power OK
19
18
Phase Fail14
2N2222
4.99K
+5V
10K
1, 2, 12, 15
J10
MegaPAC™ Family AC-DC, DC-DC Switchers