ABB CA-26 Instructions Manual - Page 10

Browse online or download pdf Instructions Manual for Relays ABB CA-26. ABB CA-26 16 pages. Percentage differential relay for bus protection class 1e applications
Also for ABB CA-26: Instruction Leaflet (16 pages)

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41-337.3L

CA-16 relay or 14 amperes to terminals 9 and 19

of the CA-26 relay. The contacts should close

when the following operating current is applied to

the relay with connections of Figure 11.

17.0 ± 7% amperes

1. CA-16

38.0 ± 7% amperes

2. CA-26

Check each individual restraint winding by apply-

ing 50 amperes to each winding. Apply sufficient

operating current to the operating circuit until the

contacts just close. The operating current should

be:

1. CA-16

3.9 to 5.1 amperes

2. CA-26

15.8 to 18.2 amperes

C. Time Curve

Apply 20 amperes to terminals 12 and 13 of the

relays. The contacts should close in the following

times:

52 ± 5% Milliseconds

1. CA-16

72 ± 5% Milliseconds

2. CA-26

D. Indicating Contactor Switch (ICS)

Close the main relay contacts and pass sufficient

dc current through the trip circuit to close the

contact of the ICS. This value of current should

not be greater than the particular ICS tap setting

being used. The operation indicator target

should drop freely.

The contact gap should be approximately 0.047

inch between the bridging moving contact and

the adjustable stationary contacts. The bridging

moving contact should touch both stationary

contacts simultaneously.

E. Indicating Instantaneous Unit (IIT) – Where sup-

plied) or Fault Detector (FD)

The core screw which is adjustable from the top

of the trip unit determines the pick-up value. The

trip unit has a nominal ratio of adjustment of 1 to

4 and an accuracy within the limits of 10%.

The making of the contacts and target indication

should occur at approximately the same instant.

Courtesy of NationalSwitchgear.com

Position the stationary contact for a minimum of

1/32 inch wipe. The bridging moving contact

should touch both stationary contacts simulta-

neously. Apply sufficient current to operate the

IIT. Fault detector unit has no target.

F. Sensitive Fault Detector (where supplied)

Apply current to terminals 14 and 15 of the relay.

The fault detector should operate between the

limits of 0.142 to 0.158 amperes.

7.2.

Routine Maintenance

All contacts should be periodically cleaned. A contact

burnisher Style number 182a836H01 is recom-

mended for this purpose. The use of abrasive mate-

rial for cleaning contacts is not recommended,

because of the danger of embedding small particles

in the face of the soft silver and thus impairing the

contact.

8. CALIBRATION

The use of the following procedure for calibrating the

relay if the relay has been taken apart for repairs or

the adjustments disturbed. This procedure should not

be used until it is apparent that the relay is not in

proper

working

order.

CHECK").

1. Contacts

Adjust the adjustable stop screw on the upper

disc of the relay so that a contact separation of

0.050 inch is obtained between the moving con-

tact and the stationary contact. Lock the screw

with the nut provided for the purpose.

2. Minimum Trip

The relay should be level for this test. Minimum

trip current can best be determined with the per-

manent magnet removed.

Adjust the spring tension until the relay just

closes its contacts with the following current

applied to terminals 12 and 13 of the relay.

1. CA-16

0.15 amperes

2. CA-26

1.25 amperes

(See

"ACCEPTANCE