35-TYPE TEST SET

Produced in 1951 by Pacific Telephone, this training film was created to show linemen the operation of the Type-35 Test Set. The film explains the use of relays in telephone work, emphasizing their need to operate and release at specific values. It describes the 35-C and 35-D Test Sets used for testing and adjusting these relays. The test sets include components like a milliammeter, telegraph keys, and variable resistors for making precise adjustments. The process involves setting up circuits with batteries, milliammeter, and variable resistances to test the relays under different conditions, such as release, operate, soak, and non-operate values. The narrator also details the steps to connect and adjust the test sets to ensure accurate relay operation.

0:44 - 1:07: Relays in telephone work are designed to operate and release at specific values, which are crucial for the circuits they are part of. These values must meet the requirements in the associated tables.

1:07 - 1:45: The 35c and 35d test sets are used for testing and adjusting apparatus on direct current (DC) bases. The 35d set can also measure external DC voltages. The apparatus is housed in a box with a removable cover and a strap for ladder attachment.

1:45 - 2:08: The main parts of the test set include a milliammeter, telegraph keys, and variable resistors. Right-hand sliders are for coarse adjustments, and left-hand sliders are for fine adjustments.

2:08 - 2:37: To establish a current flow through a relay, a battery, milliammeter, and variable resistance are connected in series. This setup allows for passing a current through the relay, checking its value, and controlling it.

2:37 - 3:01: Relays are designed to work under specific conditions, including release current values. For example, a relay might need to release at 5 milliamps.

3:01 - 3:56: Additional values like the operate value (e.g., 10 milliamps) and soak value (e.g., 150 milliamps) are considered. The relay should operate and release dependably under these values.

3:56 - 4:30: A non-operated value (e.g., 7 milliamps) is also set. The relay should not operate at this value.

4:30 - 5:06: The relay is tested by sending specific currents through its winding and checking its operation and release.

5:06 - 6:00: The circuit drawing in the test set cover can be simplified. Before connecting the test set, all sliders should be restored to the right to protect the milliammeter from overload.

6:00 - 7:07: The relay winding is connected to the test set, and the battery and ground are connected. The telegraph key is short-circuited, and the sliders are adjusted to reach the proper operate value.

7:07 - 8:13: The circuit is traced through the test set, and the relay is tested by adjusting the sliders and checking the milliammeter.

8:13 - 9:01: For a relay with ground on the winding, the test set is connected, and the sliders are adjusted to reach the release and operate values.

9:01 - 10:00: A third condition, the soak value, is added. The relay is soaked, and the operate and release values are tested.

10:00 - 11:12: For a relay with both battery and ground on its windings, the milliammeter and variable resistance are connected in series. Four conditions (release, non-operate, operate, and soak values) are set up and tested.

11:12 - 12:44: The relay is tested under all four conditions, ensuring it operates and releases correctly after soaking and under specified current values.