Page 19 of 23
17150 issue 17, October 2018
Vega DC Handbook
Cooling
Option
Max
Ambient
Input Voltage
Max
Power
Max AT
(total)
Module
Current Rating
F
50
34
344
140
100%
36
360
140
100%
44 - 75
450
180
100%
R
50
34
300
145
100%
36
320
145
100%
44 - 75
420
165
100%
C
50
See Customer Air Cooling section for ratings
Power and AT (Ampere Turns) ratings may be interpolated.
Ampere Turns is the sum of (output amps x secondary turns)
Customer Air Cooling (option C):
The following method must be used for determining the safe operation of PSUs when C option (Customer Air)
is fitted, ie fan not fitted to PSU.
For PSUs cooled by customer supplied airflow the components listed in the following table must not exceed
the temperatures given. Additionally ratings specified for units with an internal fan must still be complied with,
eg mains input voltage range, maximum output power, ampere turns, module voltage / current ratings and
maximum ambient temperature. To determine the component temperatures the heating tests must be
conducted in accordance with the requirements of IEC60950-1 Clause 4.5. Consideration should also be give
to the requirements of other safety standards.
Test requirements include: PSU to be fitted in its end-use equipment and operated under the most adverse
conditions permitted in the end-use equipment handbook/specification and which will result in the highest
temperatures in the PSU. To determine the most adverse conditions consideration should be given to the
end use equipment maximum operating ambient, the PSU loading and input voltage, ventilation, end use
equipment orientation, the position of doors & covers, etc. Temperatures should be monitored using type K
fine wire thermocouples (secured with cyanoacrylate adhesive or similar) placed on the hottest part of the
component (out of any direct airflow) and the equipment should be run until all temperatures have stabilised.
Circuit Ref.
Description
Max. Temperature (°C)
-
Power transformer primary, secondary and core
130
T1, TX101, TX201 Module current transformer windings
127
XQ1, XTR1
E, EV, F & FV Primary option transformers
90
L1, XT601
Choke winding
127
L4, T2
Choke winding
117
Various
All other choke & transformer windings
140
Various
All X capacitors and electrolytic capacitors
105
Input Connections:
Input Screw Terminals: 6-32 screws with 8.25 spacing between screw and head centres.
Srew head diameter is 6.6mm.
Output Connections:
Single slot, single output modules (B,C,L): Two 6.35mm fast-ons per output each rated
18A or M4 screw terminals rated 35A. Single slot, twin output maodules (H): One 6.35mm fast-on per output
rated 18A or M3 screw terminals rated 15A. Dual slot, single output (D, E): Two 9.5mm fast-ons per output
each rated 32A or M5 screw terminals rated 90A.
Maximum Torque Settings for Output Screw Terminals:
M3 - 0.5 - 0.6Nm,
M4 - 1.1 – 1.3Nm,
M5 - 2.4 – 2.6Nm
