Description

These 4 Way Test Blocks are used for mounting on switchboard panels for use with proper test equipments to facilitate the testing of AC instruments, meters and relays. Technical Features Type TTB4W test blocks are 4-pole blocks, provided with moulded bakelite base and covers that have an arrangement of internal plug contacts, which make a through positive connection when the cover is in place. The contacts in the blocks are of the line pressure type and provide positive contact with minimum contact resistance. For all current circuits, auxiliary contacts are used which automatically short circuit the current transformer when the cover is removed. Routine testing can be accomplished simply by removing the cover and substituting the properly connected test plug. Thereafter, normal connections are restored by replacing the cover. Contact rating is 250 volts, 10 amperes continuously. Each TTB4 Test Block includes the Test Block and cover with a set of uncounted auxiliary contacts, jumpers, and screws in sufficient variety and quantity to provide the combinations to suit any application desired. Details of the Auxilliary Contacts provided are as below: Auxiliary contact C1 is equal to one pole of contact No. 1, to be used in connection with jumper shown in Figure. Auxiliary contact C2 is used to short circuit the current transformer when the cover or plug is not in place. Auxiliary contact C3 is used as bridge to maintain the circuit during the period that the cover or the plug is not in place. Without this connection, loss of revenue is possible because of interrupted operation if the replacement of the cover or plug is long delayed. Auxiliary contact C4 jumpers is to be used in connection with auxiliary contact C2 or C4, to serve the same purpose as C2 in short circuiting a current transformer, or to interconnect phases, when the cover fastening stud is to be bypassed. The Auxiliary contacts are furnished as a standard along with each TTB4w Test Block are - C1 - 1No., C2 - 2 Nos, C3 - 4 Nos. and C4 - 1 No.