Cutler Hammer, Div of Eaton Corp DS6 Application Information

Application Data AP03900001E

Effective June 2010

How to select the correct size
DS6 soft starter for standard
duty applications

Application

The DS6 is a two phase control soft starter utilized
to accomplish motor starting using the reduced
voltage method. Typically, the motor horsepower
or kW rating is used to determine the required size
of the soft starter. This document addresses other
factors that require consideration in accomplishing
the proper match of soft starter to the load.

Overview

Soft starter sizing is typically determined by the
horsepower or kW rating of the motor, coupled
with the mains operating voltage. Using this
information, a table or graph is consulted to deter­mine the minimum size of the soft starter for the
application. If the application is considered to be
severe duty, it is commonplace to select the next
size larger soft starter to accommodate the higher
load currents.

The initial graphs and tables published for the DS6
are based on an inrush value of 300% FLA of the
motor. If the actual inrush current approaches a
value of 400% FLA, the maximum allowable ramp
times are significantly affected. Additionally, the
ramp times also must be considered indepen­dently, as when the ramp times are increased
even though the inrush current does not change,
the maximum allowable current capacity is
reduced. When selecting the size of the DS6 soft
starter, Tables 1– 4 may be used if the anticipated
ramp times are 10 seconds or less. Please note
that either 300% or 400% current limit refers to
the maximum anticipated start current in terms
of motor FLA (3x or 4x). The DS6 does not have
a current limiter function. If the ramp times are
expected to be longer, Tables 5 –12 should be
reviewed to ensure that the soft starter is not
subjected to excessive current resulting in
SCR failure. The size of the soft starter may
be required to be increased specifically due
to a longer ramp time.

ote:N The DS6 soft starter may be incorrectly sized

if based solely on motor horsepower or kW rating and
mains voltage alone.

The DS6 soft starter requires that specific
attention is given to two factors:

Ultimate load—the maximum inrush current
that the soft starter will transmit anytime during
the start process.

Ramp time—the expected, or required,
ramp time required for the motor to achieve
synchronous speed.

Example 1—30 hp motor (40A FLA) @ 460V
application, maximum current 300% FLA with
an estimated start ramp time of 8 seconds,
4 starts per hour. Consulting Table 1, the
DS6-34DSX041NO-N soft starter shows an
acceptable maximum motor size of 30 hp.
Consulting Table 5, the maximum allowable start
current is listed as 121A. Under these conditions,
a DS6-34DSX041NO-N soft starter is the
appropriate selection for this application.

Example 2—With the same operating conditions
as in Example 1, it is determined that the ramp
time must be extended to 12 seconds for the
motor to achieve synchronous speed. Consulting
Table 5, the maximum allowable start current
@ 12 seconds is listed as 104A, less than the
required 120A. Table 6 for the next higher size soft
starter lists the maximum allowable start current
@ 12 seconds as 140A. Under these conditions,
the DS6-34DSX041NO-N soft starter would not
be an appropriate selection. The next size higher
soft starter, DS6-34DSX055NO-N, is the suitable
choice, as the maximum allowable start current for
these conditions is sufficient for proper operation.

Example 3—With the same operating conditions
as in Example 1, it is determined that the inrush
current requires a 400% current limit. This operat­ing condition will also require a larger capacity
soft starter (DS6-DSX055NO-N) to accommodate
the higher operating current during the start ramp.

Application Data AP03900001E

Effective June 2010

How to select the correct size

DS6 soft starter for standard

duty applications

Table 1. 10 Second Ramp, 1 Start per Hour,
300% Current Limit @ 40°C

300%
Current Limit
10 Second Ramp

Catalog Number 200V 230V 460V Fuse

DS6-34DSX041NO-N

DS6-34DSX055NO-N

DS6-34DSX068NO-N

DS6-34DSX081NO-N

DS6-34DSX099NO-N

DS6-34DSX134NO-N

DS6-34DSX161NO-N

DS6-34DSX196NO-N

a

Maximum values are higher than allowed per NECT 430.52 and ULT 508A 31.1.

Rated
Current
(A)

40 10 10 30 HFD3150L 150A Class RK5

52 15 20 40 HFD3200L 200A Class RK5

65 20 25 50 HJD3250 200A Class RK5

77 25 30 60 HKD3300 300A Class RK5

96 30 30 75 HKD3350 350A Class RK5

124 40 50 100 HKD3350 500A Class RK5

156 50 60 125 HLD3450 500A Class RK5

180 60 75 150 HLD3500 500A Class RK5

Motor Power (hp)

Breaker

4/hr @ 40°C

a

Table 2. 10 Second Ramp, 1 Start per Hour,
400% Current Limit @ 40°C

400%
Current Limit
10 Second Ramp

Catalog Number 200V 230V 460V Fuse

DS6-34DSX041NO-N

DS6-34DSX055NO-N

DS6-34DSX068NO-N

DS6-34DSX081NO-N

DS6-34DSX099NO-N

DS6-34DSX134NO-N

DS6-34DSX161NO-N

DS6-34DSX196NO-N

a

Maximum values are higher than allowed per NEC 430.52 and UL 508A 31.1.

Rated
Current
(A)

27 7.5 10 20 HFD3150L 150A Class RK5

34 10 10 30 HFD3200L 200A Class RK5

40 15 15 30 HJD3250 200A Class RK5

52 15 20 40 HKD3300 300A Class RK5

65 20 25 50 HKD3350 350A Class RK5

80 30 30 75 HKD3350 500A Class RK5

96 30 40 75 HLD3450 500A Class RK5

124 40 50 100 HLD3500 500A Class RK5

Motor Power (hp)

Breaker

4/hr @ 40°C

a

Table 4. 10 Second Ramp, 1 Start per Hour,
400% Current Limit @ 40°C

400%
Current Limit
10 Second Ramp

a

Catalog Number 230V 400V Fuse

DS6-34DSX041NO-N

DS6-34DSX055NO-N

DS6-34DSX068NO-N

DS6-34DSX081NO-N

DS6-34DSX099NO-N

DS6-34DSX134NO-N

DS6-34DSX161NO-N

DS6-34DSX196NO-N

a

Maximum values are higher than allowed per NEC 430.52 and UL 508A 31.1.

Rated
Current
(A)

28.8 7.5 11 HFD3150L 150A Class RK5

37.5 11 18.5 HFD3200L 200A Class RK5

46 11 22 HJD3250 200A Class RK5

56 15 30 HKD3300 300A Class RK5

68 18.5 37 HKD3350 350A Class RK5

90 22 45 HKD3350 500A Class RK5

106 30 55 HLD3450 500A Class RK5

134 37 75 HLD3500 500A Class RK5

Motor Power (hp)

Breaker

4/hr @ 40°C

a

a

Supporting documentation

Manuals Reference Number

DS6 Instructional Leaflet IL03901001E

a

DS6 Catalog CA03901001E

Program Files none

Outline Drawings none

ote:N In the event that additional help is needed, please contact the Technical

Resource Center at 1-877-ETN-CARE, Option 2, Sub Option 2.

Table 3. 10 Second Ramp, 1 Start per Hour,
300% Current Limit @ 40°C

300%
Current Limit
10 Second Ramp

Catalog Number 230V 400V Fuse

DS6-34DSX041NO-N

DS6-34DSX055NO-N

DS6-34DSX068NO-N

DS6-34DSX081NO-N

DS6-34DSX099NO-N

DS6-34DSX134NO-N

DS6-34DSX161NO-N

DS6-34DSX196NO-N

a

Maximum values are higher than allowed per NEC 430.52 and UL 508A 31.1.

Rated
Current
(A)

41 11 22 HFD3150L 150A Class RK5

55 15 30 HFD3200L 200A Class RK5

68 15 37 HJD3250 200A Class RK5

81 22 45 HKD3300 300A Class RK5

99 30 55 HKD3350 350A Class RK5

134 30 75 HKD3350 500A Class RK5

161 45 90 HLD3450 500A Class RK5

196 55 110 HLD3500 500A Class RK5

Motor Power (hp)

Breaker

4/hr @ 40°C

a

a

2

EATON CORPORATION www.eaton.com

How to select the correct size
DS6 soft starter for standard
duty applications

Application Data AP03900001E

Effective June 2010

Table 5. DS6-34DSX041NO-N

41 Amps Maximum Starting Current

Ramp Time 1/hr 25°C 1/hr 40°C 4/hr 40°C 10/hr 40°C 20/hr 40°C

0.001 155A 136A 133A 129A 127A

3 152A 133A 131A 129A 127A

4 150A 131A 128A 126A 124A

5 149A 129A 126A 124A 121A

6 146A 128A 125A 121A 118A

7 145A 126A 123A 119A 115A

8 144A 125A 121A 117A 113A

9 142A 124A 120A 115A 111A

10 142A 123A 118A 114A 108A

12 123A 111A 104A 98A 94A

13 121A 108A 102A 96A 91A

15 117A 105A 99A 92A 87A

19 112A 101A 93A 86A 80A

20 111A 100A 92A 84A 79A

23 109A 97A 89A 81A 73A

26 108A 96A 87A 79A 67A

29 106A 94A 85A 77A 62A

30 105A 94A 85A 76A 60A

Table 6. DS6-34DSX055NO-N

55 Amps Maximum Starting Current

Ramp Time 1/hr 25°C 1/hr 40°C 4/hr 40°C 10/hr 40°C 20/hr 40°C

0.001 209A 183A 178A 173A 170A

3 204A 178A 176A 173A 170A

4 201A 175A 172A 169A 166A

5 199A 173A 170A 166A 162A

6 196A 171A 167A 163A 158A

7 195A 169A 164A 160A 155A

8 193A 168A 162A 157A 152A

9 191A 166A 160A 155A 148A

10 190A 165A 159A 153A 145A

12 165A 148A 140A 132A 126A

13 162A 145A 137A 129A 121A

15 157A 141A 132A 123A 116A

19 150A 135A 125A 115A 108A

20 149A 134A 123A 113A 106A

23 146A 131A 120A 109A 98A

26 144A 129A 117A 106A 89A

29 142A 127A 115A 103A 83A

30 141A 126A 114A 102A 81A

Table 7. DS6-34DSX068NO-N

68 Amps Maximum Starting Current

Ramp Time 1/hr 25°C 1/hr 40°C 4/hr 40°C 10/hr 40°C 20/hr 40°C

0.001

258A 226A 220A 214A 210A

3 253A 221A 217A 214A 210A

4 249A 217A 213A 209A 205A

5 246A 214A 210A 205A 200A

6 242A 212A 207A 201A 195A

7 241A 209A 203A 198A 191A

8 239A 208A 201A 194A 187A

9 236A 205A 198A 191A 183A

10 235A 204A 196A 189A 180A

12 204A 183A 173A 163A 155A

13 200A 180A 169A 159A 150A

15 194A 174A 164A 153A 144A

19 186A 167A 155A 142A 133A

20 185A 166A 153A 140A 131A

23 181A 162A 148A 135A 121A

26 178A 159A 145A 131A 110A

29 176A 157A 142A 127A 103A

30 174A 155A 140A 126A 100A

Table 8. DS6-34DSX081NO-N

81 Amps Maximum Starting Current

Ramp Time 1/hr 25°C 1/hr 40°C 4/hr 40°C 10/hr 40°C 20/hr 40°C

0.001

307A 269A 262A 255A 251A

3 301A 263A 259A 255A 251A

4 296A 258A 254A 249A 245A

5 293A 255A 250A 245A 238A

6 289A 252A 246A 240A 232A

7 287A 249A 242A 235A 228A

8 284A 248A 239A 231A 223A

9 281A 245A 236A 228A 219A

10 280A 243A 234A 225A 214A

12 243A 219A 206A 194A 185A

13 238A 214A 202A 190A 179A

15 231A 208A 195A 182A 171A

19 222A 199A 184A 170A 159A

20 220A 197A 182A 167A 156A

23 215A 193A 177A 160A 144A

26 212A 190A 173A 156A 131A

29 209A 186A 169A 151A 122A

30 208A 185A 167A 150A 119A

EATON CORPORATION www.eaton.com

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