Danfoss VLT Pocket Guide

40 VLT
®
Soft Starter Pocket Guide
Soft starters are much more fl exible than star/delta starters and provide
a smooth start with no risk of current or torque transients.
Star/delta starters cannot accommodate varying load conditions (e.g.
loaded or unloaded starts) and the start torque cannot be adjusted to
match motor and load characteristics. In addition, the open transition
between star and delta connection causes damaging torque and
current transients. Star/delta starters are not capable of providing soft
stop.
Star/delta starters may be cheaper than a soft starter and they may limit
the start current to a lower level than a soft starter when used on an
extremely light load. However, damaging current and torque transients
may still occur.
Star/Delta Starters: How does soft start compare
with star/delta starting?

Danfoss VLT Specifications

General

Frequency	50/60 Hz
Enclosure	IP20, IP21, IP55, IP66
Series	VLT
Control Technique	Flux Vector Control
Output Voltage	0-Vinput
Control Method	Fieldbus
Communication Interface	PROFIBUS, CANopen
Protection Features	Overload, Overvoltage, Undervoltage, Short Circuit, Ground Fault
Cooling Method	Liquid Cooled
Storage Temperature	-25°C to +70°C
Relative Humidity	5-95% non-condensing
Altitude	Up to 1000m (3280ft) without derating, up to 4000m (13120ft) with derating
Operating Temperature	-10°C to +50°C (14°F to 122°F)