Specifications

12
1-800-927-9474
20-14
DC MegaPAC Interface Connections (cont)
of 42V), a fast-blow fuse of 50 Amps is recommended. Start-up inrush current is limited by a
10Ω thermistor and in most cases will be less than nominal line current during operation.
Start-up inrush current can be calculated by I = MaxVin/10 (where MaxVin is the maximum
operating voltage, see Table 1, page 20-16). Example: for a nominal 48V input, the maximum
operating voltage is 60V, therefore, I = 60V/10 = 6 Amps.
NOTE: An input fault clearing device such as fuse F1, or a circuit breaker is required per safety agency
conditions of acceptability.
Signal Ground (J10-1,2,12,15)
Signal Ground on J10-1, 2, 12 and 15 are isolated secondary ground references for all J10
interfacing signals. This is not the same as Earth Ground on input power connector J9.
Enable/Disable (J10)
The Enable/Disable control pins allow ConverterPAC outputs to be sequenced either on or off;
see outline drawing for locations. For DualPACs, both outputs are sequenced together. In
parallel arrays, only the driver ConverterPAC need be controlled. The Enable/Disable pins
should be pulled low to less than 0.7V with respect to Signal Ground to disable the outputs.
They will source 8 mA maximum. These pins should be open circuited or allowed to exceed
4.5V when enabled. Do not apply more than 8V to these inputs at any time. If driven from an
electromechanical switch or relay, a capacitor should be connected to eliminate the effects of
switch bounce.
General Shutdown (GSD) (J10-5)
The GSD control pin on J10-5 allows simultaneous shutdown of all ConverterPAC outputs. This
pin must be pulled low to less than 0.7V, and will source 8 mA maximum to shut down all
outputs. The GSD pin should be open circuited or allowed to exceed 4.5V when not in use, or
when the outputs are to be enabled. Do not apply more than 8V to this input at any time. Normal
open circuit voltage is 1.5 to 3V with respect to Signal Ground. If driven from an electromechanical
switch or relay, a capacitor should be connected to eliminate the effects of switch bounce.
Applications Manual
DC MegaPAC
J9 Input Power Connection
3
2
1
Input: 12, 24, 36, 48 or 72Vdc
+
–
F1
+ Vin
–Vin
Earth Ground
Figure 19.
Input Connector J9
DC MegaPAC
24
1
5
Signal Ground
General Shutdown
Enable/Disable Output 1
J10
Enable/Disable Control
1
0
TTL "1" (OFF)
TTL "0" (ON)
A TTL "1" applied to the base of the transistor turns
output OFF. Pin 24 (or Pin 5 for GSD) is pulled Low
with respect to Signal Ground.
16
Vcc
Figure 20.
Enable/Disable
and General
Shutdown