Capacitor Switching Contactors

Frako Capacitor Switching Contactors

Advanced Technology Contactors extend both Contactor and Capacitor life!

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FRAKO Capacitor Switching Contactors are specifically designed for capacitor switching to achieve reliability and long life expectancy for your capacitor system. 

FRAKO Contactors are available with or without pre-charge resistors.

Frako Power Factor Correction Capacitors
Contactors with pre-charge resistors (K3-…K… type)

Modern capacitor systems use special contactors that are equipped with resistors to suppress the switching currents. The resistors are switched in series with the capacitor prior to the closing of the main contacts and removed from the circuit after energization, so as not to cause additional power losses.

This feature is referred to as leading transition contact with pre-charge (or pre-insertion) resistor and offers these advantages:

  • Significant damping of inrush current
  • Suppression of voltage transients during switching
  • Protection for both capacitor and contactor
  • Extended capacitor and contactor life
  • May be used with and without series reactors
  • Increased system reliability
Contactor with Pre-charge Resistors

Contactor with Pre-charge Resistors

Part No.

Max AMP Rating
at 50°C

208 V

240 V

480 V

600 V

Cell
Cell

Select by Kvar (range)

K3-18NK10-110

0-18

0-6

0-7

0-15

0-18

K3-24K00-110

14-28

4.5-10

5.5-11

11.5-25

14.5-30

K3-32K00-110

14-36

4.5-12.5

5.5-15

11.5-30

14.5-35

K3-50K00-110

30-48

10-16.7

12.5-20

25-40

31-50

K3-62K00-110

30-72

10-25

12.5-30

25-60

31-75

K3-74K00-110

30-108

10-32

12.5-36

25-72

31-90

K3-90K00-110

50-115

17-40

20-47

40-95

50-120

K3-115K00-110

50-144

17-46

20-56

40-114

50-143

Contactors without pre-charge resistors (K3-…A… type)

Capacitors with series reactors (for tuning or detuning) have lower peak inrush current than systems that do not include reactors. For these applications, FRAKO offers contactors with special wear-resistant contact material which enables them to switch the reactor/capacitor network without the need for pre-charge resistors. These special contactors offer several advantages for capacitor switching applications that include series-connected reactors: Safe switching (ON and OFF) of reactor/capacitor steps

  • Improved voltage quality made possible through chatter-proof switching operations
  • Extended capacitor life
  • Extended contactor life (>100,000 switching operations)
  • Increased system reliability

Call us 1-262-618-2403, Email or visit our Contact us page for Application Engineering or Quotes for Capacitor Switching Contactors.

contactor-without-resistor

Contactor without Pre-charge Resistor

Maximum Current (continuous):

K3-..K Contactors
(with resistors)

K3-18NK

K3-24K

K3-32K

K3-50K

K3-62K

K3-74K

K3-90K

K3-115K

Amps in 50°C ambient

0-18

14-28

14-36

30-48

30-72

30-108

50-115

50-144

Amps in 60°C ambient

0-18

14-28

14-36

30-48

30-72

30-87

50-108

50-130

K3-..A Contactors
(w/o resistors)

K3-18ND

K3-24A

K3-32A

K3-50A

K3-62A

K3-74A

K3-90A

K3-115A

Amps in 50°C ambient

18

28

36

48

32

108

115

144

Amps in 60°C ambient

18

28

36

48

72

87

108

130

General Specification:

Parameter

K3-18

K3-24

K3-32

K3-50

K3-62

K3-74

K3-90

K3-115

Maximum Voltage

600V

600V

600V

600V

600V

600V

600V

600V

Switching Time (msec)

8-16

10-25

10-25

12-28

12-28

12-28

20-35

20-35

Typical RK5 Fuse (A)

50

90

125

200

250

300

300

300

Typical T Fuse (A)

70

110

150

175

175

175

300

300

Power Loss (Watts)

3.5 W

4.7 W

5.3 W

9.2 W

10.9 W

12.5 W

9.3 W

11.0 W

Terminal capacity Flexible (awg)

2x(18-10)

1x(14-4)

1x(14-4)

1x  (10-0)

1x (18-3/0)  plus1x (8-4/0)

Terminal capacity Solid (awg)

2x(18-10)

1x(16-10)

1x(16-10)

1x(12-10)

1x(12-10)

1x(12-10)

Use flexible wires

Coil Voltage range

85% to 110% of rated coil voltage

Coil Terminals Flexible (awg)

18-12

18-12

18-12

18-12

18-12

18-12

18-12

18-12

Coil Terminals Solid (awg)

14-12

14-12

14-12

14-12

14-12

14-12

14-12

14-12

Weight (kg)

0.34

0.62

0.62

1.0

1.0

1.0

2.3

2.3

UL Approval

File # E 41502  for USA and Canada (UL-508)

Frako Power Factor Correction Capacitors
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