Danfoss VLT Pocket Guide

VLT
®
Soft Starter Pocket Guide 25
Key Benefi ts: What are the key benefi ts of soft start?
Soft start enhances motor start performance in many ways.
The gradual application of voltage or current avoids the voltage •
and current transients associated with electro-mechanical reduced
voltage starters.
Acceleration is also smoother, as soft start avoids the torque •
transients associated with electro-mechanical reduced voltage
starters.
Constant current control gives higher torque as motor speed •
increases, resulting in lower start currents and/or shorter start times
Start performance can be adjusted to suit the motor and load, •
including exact control over the current limit.
Soft starting provides reliable performance even with frequent •
starts, or if load characteristics vary between starts (e.g. loaded or
unloaded).
Soft starters also provide a range of features not available from other
reduced voltage starters. This includes soft stop, which helps eliminate
water hammer and DC braking.
Other features such as built-in protection for the motor and
system, and metering and monitoring options, can reduce
the overall installed cost of the equipment and reduce the
long-term maintenance requirement.

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)