Danfoss VLT, Pocket Manual, Page: 13 / 64

VLT ® Soft Starter Pocket Guide 13
AC53 utilisation codes describe the current rating for soft starters
under specifi ed operating conditions.
The utilisation code determines the maximum motor size the soft
starter can be used with, under the specifi ed conditions. The current
rating may change under diff erent operating conditions.
AC53a: Non-bypassed soft starters
The rating depends on the number of starts per hour, the length and
current level of the start, and the percentage of the operating cycle
that the soft starter will be running (passing current).
AC53b: Bypassed soft starters
The rating depends on the number of starts per hour, the length and
current level of the start, and the amount of time the soft starter will be
off (not passing current) between starts.
Danfoss soft starters provide a relay output, which can be
used to control the main contactor. Ensure that the inrush VA
rating of the contactor coil does not exceed the rating of the
soft starter’s relay input.
AC53 Utilisation Codes: What are AC53 Utilisation Codes?