ABB CA-26 Petunjuk Manual - Halaman 7

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Figure 10: External Schematic of the Type CA-26 Relay for Transformer Protection and Bus Protection.

4.5.

ENERGY REQUIREMENTS

Burden of each restraint coil at 5 amperes

VOLT AMPERES

.75

Continuous Rating

1 second rating

Burden of Operating Circuit

VOLT AMPERES

Variable (see Figure 7)

Continuous rating 8 amperes

1 second rating 280 amperes

Courtesy of NationalSwitchgear.com

4.6.

4.6.1. CA-16

To determine the ac connections, identify each pri-

POWER FACTOR

mary circuit as either a "source" or "feeder". As

defined here, a feeder contributes only a small por-

tion of the total fault-current contribution for a bus

14 amperes

fault. Next lump a number of feeders into a "feeder

group" by paralleling feeder ct's, taking the precau-

460 amperes

tion that each feeder group has less than 14 amperes

load current (restraint coil continuous rating). If the

bus reduces to more than four circuits, parallel ct's

until only four circuits remain. Then connect these

ct's to the relays per Figure 8.

The four circuit bus arrangement of Figure 8 must be

used with caution. Tripping speed is dependent on

the net torque (operating minus restraint) applied to

the two induction discs. Restraint torque is zero if the

contribution from each of the four circuits is equal

and the operating time of the relay is as described by

Figure 6. On the other hand, restraint torque is

CONNECTIONS

41-337.3L

Sub 3

606B269