External input protection, Using only 2 legs of a 3-phase system – Rockwell Automation 1606-XLE240F-3 Power Supply Reference Manual User Manual

Page 19

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All parameters are specified at 24V, 2.5A, 230Vac input, 25ªC ambient and after a 5 minutes run-in time unless noted otherwise.

Rockwell Automation Publication 1606-RM031A-EN-P — April 2014

19

Bulletin 1606 Switched Mode Power Supplies

22.5. External Input Protection

The unit is tested and approved for branch circuits up to 30A (U.S.A.) and 32A (IEC). An external protection is only
required, if the supplying branch has an ampacity greater than this. Check also local codes and local requirements. In
some countries local regulations might apply.

If an external fuse is necessary or utilized, minimum requirements need to be considered to avoid nuisance tripping of
the circuit breaker. A minimum value of 6A B- or 3A C-Characteristic breaker should be usee.

22.6. Using Only 2 Legs of a 3-Phase System

oss

e

The power supply is allowed to run permanently on two legs of a 3-phase
system, when the output power is reduced according to the curves below. A
long-term exceeding of these limits will result in a thermal shut-down of the
unit. No external protection device is required to protect against a phase-l
failure. EMC performance, hold-up time and losses differ from a three phas
operation. Therefore, check suitability of your individual application. The
screw of the terminal which remains unused must be securely tightened.
Using only two legs of a 3-phase system is not included in the UL approval. Therefore, additional testing might be
necessary.

DC

L1
L2
L3

open

AC

L1

L2

L3

PE

Power Supply

Fig. 22-4

Allowed output current for use on only two

legs of a 3-phase system

Fig. 22-5

Hold-up time for use on only two legs

of a 3-phase system

Allowed Output Current at 48V

0

-25

0

20

70°C

1

2

3

4

5

6A

40

60

Ambient Temperature

A

B

A... 2x 340-576Vac, 3x 320-576Vac
B... 2x 320-340Vac

0

20

40

60

100ms

320

360

400

440 2x480Vac

Input Voltage

Hold-up Time at 48Vdc

2.5

A,

ty

p.

5A,

typ

.

5A,

min

.

2.5

A,

mi

n.

80

Fig. 22-6

Efficiency vs. output current at 24V for use on

only two legs of a 3-phase system

Fig. 22-7

Losses vs. output current at 24V for use on

only two legs of a 3-phase system

Efficiency

1

89

91

93

88

94%

6A

2

4

5

Output Current

3

90

92

2x400Vac

2x480Vac

Power Losses

0

1

2

4

5

6A

0

4

12

20

24W

2x480Vac

2x400Vac

8

3

16

Output Current

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