UL 917-2016 pdf download

UL 917-2016 pdf download.Clock-Operated Switches.
28.4 A switch intended for pilot duty shall perform acceptably when operated for the number of cycles indicated in Table 28,1, making and breaking a circuit 01 rated frequency, at the voltage indicated in 24.4 and at the rate of operation indicated in 28.5. The load shall consist of an electromagnet representative ot the rnagnet•coil load that the device is intended to control, The normal current, which is the test current, is to be determined from the voltage and volt-ampere rating of the device. For an alternating-current device, the power factor shall not be more than 0.35 and the inrush current shall be ten times the normal current. The test shall be conducted with the armature of the load, if any, free to move, that is. not blocked in either the opened or dosed position. The device shall be electrically and mechanically operable at the conclusion of the test. at which time the switch shall be capable of performing its intended function and shall show no wear, loosening of parts. or defects of any other description that will diminish appreciably the usefulness of the switch.
28.5 Unless the nature of the device requires a longer time to complete a cycle of operation, the rate of speed of operation for the test mentioned In 28.4 shall be as follows:
a) For a device intended to be operated manually, the first 1000 cycles shall be at the rate of 1 cycle per second — except that the first 10 or 12 operations shall be made as rapidly as
possible — and the remaining cycles shall be at the rate of 6 cycles per minute, with the device closed for approximately 1 second of each cycle.
b) Where there is no provision for manual operation, the entire number of cycles shall be at the rate of 6 cycles per minute. with the device closed for approximately 1 second each cycle.
29 Tungsten-FIlament-Lamp Load Test
29.1 A switch with a tungsten lamp rating of not more than 60 A is to be tested with a tungsten-filament-lamp load so adjusted that the current flow Is the rated current of the switch. The test circuit shall have such ampere capacity as to provide a current inrush through the switch arid load ot not less than ten times the rated current when the circuit is closed on a load equal to the switch rating, but not less than 20 A, and the circuit shall be such that the peak value of inrush current will be reached within 1/240 of a second after the circuit is closed,
292 A synthetic load and a combination synthetic and tungsten-filament lamp load for testing on alternating current shall be investigated as described in 29.3 and 29.10, and also with respect to special conditions which are introduced by use on alternating current.
29.3 The acceptability of a test circuit, inclung the generator or other source of supply, for testing with tungsten-filament lamps is to be determined by means of oscillograph studies. With reference to a 60 Hz timing wave, the peak values of inrush current as shown by oscillograms are to be reached within 114 cycle.
29.4 A tungsten-filament-lamp load and the supply circuit need not provide the inrush current required for
a 20 A load ii when tested for a lower current rating the available inrush current is adequate for the lower
rating and testing is limited to the lower rating as a maximum.
29.5 The characteristics of a direct-current test circuit are to be determined from a number of oscillograms, 12 or more, and testing equipment is acceptable if not less than half the oscillograms show the minimum acceptable or a greater current-inrush factor.