Patent GB-989628-A (GB)
Title: Condenser tester
Inventor: RAYBURN CHARLES CALVIN
IPC: G01R31/01
Filed: 1961-07-27
Abstract: 989,628. Impedance and fault testing. ILLINOIS TOOL WORKS Inc. July 27, 1961, No. 27220/61. Heading G1U. [Also in Division B8] Apparatus testing capacitors includes an inclined shoot for gravitational travel of a series of capacitors, means for testing dielectric strength and/or capacitative reactance positioned intermediately of the ends of the shoot and include alternately movable upper and lower spaced gates, electrically operable means controlled by a cycling switch for opening the upper gate to permit a capacitor to move down the shoot and against the lower gate for testing, electrically operable means controlled by a cycling switch for opening the lower gate to permit discharge of the capacitor after test, a first means located in the shoot above the upper gate for retaining a column of capacitors against gravitational movement, and second means interposed between the first means and the upper gate for releasing the lower capacitor of the column for movement to the lower gate. A nonconductive plastic shoot A (Fig. 1) of U- section with a dependent trough (Fig. 7 not shown) is bolted at 1 to vertical wall 2 (Fig. 2) to lie at 45 degrees to the vertical, and contains an end-to-end series of capacitors S. Gates B 1 , B 2 , B 3 , B 4  are disposed along the line of the shoot of which B 1  is operated by rotary solenoid C 1 ; B 2  and B 3  are linked to be opened together in respectively anticlockwise directions by rotary solenoid C 2 ; and B 4  is operated by rotary solenoid C 4 . The solenoids (Fig. 10 not shown) each comprise a ring electromagnet, inwardly attracting an armature and axial shaft supported by ballbearings, with inclined cam grooves to develop a rotary motion for operating an associated gate as well as the axial motion which is absorbed by a withdrawable toothed clutch coupling. Gate B 1  (Fig. 2) comprises an elongated tapered tongue 25 inclinedly interposed between two adjacent capacitors in the shoot and transversely fixed to the clutch shaft of the solenoid C 1 , while gate members B 2 , B 3 , B 4  have hubs 31, 35, 36 fixed to the shafts which carry extensions 32, 38 to which are bolted dependent metal fingers 34, 39 at right angles to the shoot; the extensions 38 of B 3 , B 4  being of insulating material so that the fingers 39 when parallel connect to the end contacts of an interposed capacitor and are in turn connected to external test circuits. A terminal section D of the shoot is orientable by rotary solenoid C 4  to direct emergent capacitors into reject or accept bins H or G. The gate operating solenoids are energized for position sequence by switches J 1 , J 2 , J 3  operated by motor driven cams K, L (Fig. 6 not shown). During an operational cycle (Figs. 1, 8) switch J 1  is initially released by cam K to connect the supply from battery P or smoothed rectifier N through solenoids C 1 , C 3  and limiting resistor 67. Gate B 1  opens allowing the capacitors to slide down to gate B 2  and gate B 4  opens allowing an already tested capacitor to emerge from the test position. Switch J 1  is then restored to close gates B 1  and B 4  with a capacitor S ready for admission to the test position. Switch J 2  is then actuated to open and then close the circuit between terminals 50, 51, (Fig. 8) to prepare a test circuit (see below) and switch J 2  is closed to energize solenoid C 2  over terminals 69 of J 1  (Fig. 8). Gates B 2 , B 3  open allowing the capacitor to slide into the test position until arrested by closed gate B 4 . Upon opening of switch J 3  by further rotation of cam K 1  solenoid C 2  is de-energized to close gates B 2 , B 3  and a test voltage from supply 68 is applied to the capacitor over gates B 3 , B 4  on closure of switch M by cam L. Satisfactory testing joins contacts 76a, 76b externally to energize solenoid C 4  to move shoot D into the accept position. Switch M is then restored by cam L to remove the test voltage and shortcircuit the charge on the capacitor to earth, after which switch J 1  is operated by cam K to open gates B 4  and release the capacitor. In testing, when supply 68 (Fig. 1) is connected through switch M and resistor 83 across the test capacitor in gates B 3 , B 4  a positive voltage is applied to grid 87 of discharge tube V 2  over potentiometer R 2  if the capacitor insulation is satisfactory; thus firing V 2  from A.C. supply 85 to energize relay T 2 . The charging current into the capacitor develops a positive transient across potentiometer R 1  to the grid of discharge tube V 1  which fires if the capacitance exceeds a minimum to energize relay T 1  from a rectified A.C. supply. Closure of contacts of T 1 , T 2  energizes solenoid C4 to direct shoot D to the accept bin, but an insulation or capacitance fault directs it to the reject bin. Conduction of V 1  is terminated by opening switch J 2  by cam M in the operating cycle, and contacts of relay T 2  are held closed for removal of the test voltage until the capacitor passes over shoot D by capacitor C 5  across the relay winding. Standards of insulation and capacitance are set by adjustment of R 1 , R 2 .