Parker Products ViX250AE - Manual (Page 125)

118 VIX AE SERVO DRIVE USER GUIDE
The size of transformer required for a servo drive installation depends very much on the
application and on the maximum shaft power delivered by individual motors.
It is worth noting that in a one-off or low volume application it is usually preferable to be
slightly generous in sizing the transformer, rather than spend a great deal of engineering
effort trying to calculate the minimum possible rating. In low-power systems the potential
savings in transformer cost are not large, although size and weight may also be a
consideration. In a higher volume application the same principles apply to the prototype
installation, but measurements of the supply current drawn under working conditions will give
a useful guide to the final specification required.
Fuses
Fuses should be time delay, high breaking capacity and should be rated for the number of
drives and expected in-rush current.
AC Fuse
The secondary AC fuse is intended to protect power supply components and should have a
value twice that of the bridge rectifier current rating.
Line Fuse
Fit line fuses to protect the transformer primary and associated wiring. If you cannot identify
the live wire, fuse both phase conductors. Calculate the fuse value using:
1.5
× VA
supply volts
in amps, but needs to be a minimum of 2A to cope with the
in-rush current.
Fuse types should be anti-surge HBC (High Breaking Capacity).
Note: If the application requires a power dump, use a Digiplan power supply such as the
PL1100.
CAUTION
Ensure that all power supply components are mounted away from operator access, as
high voltages and hot surfaces are present in normal operation.