Danfoss VLT Pocket Guide

22 VLT
®
Soft Starter Pocket Guide
Inside delta Connection:
What is “inside delta” connection?
With inside delta (six wire connection), the soft starter SCRs are in series
with each motor winding so that the soft starter carries only phase
current, not line current. The soft starter can thus control a motor with
greater full load current than normal.
Inside delta connection is only possible with motors that allow each
end of all three motor windings to be connected separately, and not
all soft starters can be connected using inside delta. A line contactor or
shunt trip MCCB must always be used to disconnect the motor and soft
starter from the supply in the event of a trip.
Inside delta connection simplifi es replacement of star/delta starters
because the existing wiring can be used. In new installations, inside
delta connection may reduce the size and cost of the soft starter, but
there are additional costs for the line contactor/shunt trip MCCB and
extra cabling.
MCD 200 soft starters cannot be installed using
inside delta connection.
MCD3000 soft starters can be installed using an inside
delta connection (models MCD3185 ~ MCD3800 only; an
additional installation kit is required).

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)