Speedfax 2017

Reduced Voltage Heavy Duty Starters
Features and Benefits
Revised on 03/31/20
General
Siemens manufactures the three commonly
used electromechanical reduced
voltage starters. Each one is designed
for specific application requirements
and consists of auto transformer,
wye-delta and partwinding starters.
The reduced voltage starter:
b Reduces inrush current
b Provides smoother acceleration of the
load
b Reduces starting torque
b Reduces stresses on mechanical
linkages
Combination and non-combination
reduced voltage starter sizes range
from 0 to 6 including Siemens exclusive
motormatched half-sizes. Enclosure
types include 1, 3R/12, 4 painted and
4/4X stainless steel. UL listed file
#E14900 (class 36); file #E185287
(class 37). CSA certified file #LR 6535
(class 36 & 37).
NEMA & General
Purpose Control
17
CONTROL
PRODUCTS
Auto Transformer Starter
b Maximum torque per amp
b Three coil auto transformer for balanced
starting currents
b 50, 65 and 80% voltage taps
b Closed circuit transition
b Adjustable starting time
b Solid-state OLR overload as standard
b CPT supplied as standard
b Wide range of factory modifications
Wye-Delta Starter
b Lowest starting torque
b Closed or open circuit transition
b Adjustable starting time
b Solid-state OLR overload as standard
b CPT supplied as standard
b Wide range of factory modifications
Various Methods of Electro-Mechanical Reduced Voltage Motor Starting
—A General Comparison
Part-Winding Starter
b Simplest design – most economical
b Adjustable starting time
b Solid-state OLR overload as standard
b CPT supplied as standard
b Wide range of factory modifications
Autotransformer Part-Winding Wye-Delta
50% 65% 80%
Characteristic Tap Tap Tap 2 step
Starting current drawn from
line as % of that which would 25% 42% 64% 65% 33%
be drawn upon full voltage
starting
Starting current drawn by the
motor
50% 65% 80% 65% 58%
Starting torque developed as
25% 42% 64% 40% 33%
% of that which would be
Increases slightly
developed on full voltage
with speed
starting
Smoothness of acceleration First in order of Third in order of Second in order of
Smoothness Smoothness Smoothness
Allowable accelerating times 15 seconds at 200HP
(typical) max. or 30 seconds on 5 seconds max. 5-60 seconds
200HP based on Limited by motor Limited by motor
NEMA medium duty design design
transformers
Starting current and torque Adjustable within limits
and adjustments
of various taps
Fixed
Fixed
17-34
Siemens Industry, Inc. SPEEDFAX Product Catalog