UL 1638A-2016 pdf download
UL 1638A-2016 pdf download.Visual Signal Appliances for General Signaling Use.
14.10 A temperature is considered to be constant when three successive readings, measured at not less than 5-minute Intervals, indicate no change.
14.11 The appliance under test is to be connected to a maximum source of supply voltage or power and operated for at least 1 hour or until stable temperatures are obtained under intended service conditions deemed likely to produce the highest temperatures.
14.12 An appliance intended to produce a signal as long as its energizing circuit is closed is to be operated for a continuous signal; except that an appliance marked to indicate intermittent duty cycles is to be operated at such duty cycles.
15 Endurance Test
15.1 A visual signaling appliance shall operate during and upon completion of the tests specified in 15.2 without risk of fire or shock hazard.
152 The appliance is to be operated for for 72 hours of alternate 5-minute periods of being energized and de-energized from maximum rated voltage or power.
16 Component Failure Test
16.1 The stress level of a component shall not exceed 90 percent of its rating. For capacitors. the voltage drop developed across the capacitor is to be measured and the stress level is to be obtained by dividing measured voltage by the rated voltage of the capacitor. All other type of components shall be evaluated for operation at 90 percent ot the manufacturer’s maximum power rating.
Exception. When an open or short in the capacitor has no effect upon p,roper operation of the appliance or would result in a system trouble signal. derating is not required.
16.2 An open or short-circuit malfunction of any component located In a high-voltage circuit (greater than or equal to 30 V rms or 42.4 V DC or peak) shall not introduce the risk ot tire or electric shock. For multiport devices, the component shall be tested with each part individually faulted.
16.3 To determine compliance with 16.2, the product is to be conditioned as follows:
a) Energized from maximum rated voltage;
b) Any interchangeable fuse replaced with a tuse of the highest available current rating which fits the fuseholder:
C) The appliance covered with a single layer of bleached cheesecloth fabricated at 14 — 15 square yards to the pound (26 —28 m2/kg) and having a thread count of 32 by 28, loosely draped over the product; and
d) The enclosure, when of metal, connected to ground through a fuse rated to correspond to the input rating of the appliance.
First, an open, and then a short-circuit, are to be individually applied to the component. Each fault condition is to be maintained until ultimate Conditions are reached as determined by constant temperatures or burnout.
17 Abnormal Operation and Burnout Test
17.1 A unit which is normally intended to be operated for a limited period, and is capable of being operated continuously under abnormal conditions, shall be capable of such extended operation without resulting in the risk of fire.
17.2 To determine when a unit complies with the requirement in 17.1 it is to be operated under the most severe abnormal conditions that will be encountered in service, and while connected to a maximum rated source of supply. The test shall not cause emission of flame or molten metal, or any other manifestation of a risk of fire.
17.3 In determining when a unit complies with the requirement with regard to installation-wiring circuit fault conditions, the fault conditions are to be maintained continuously until constant temperatures are attained, or until burnout occurs, when the fault does not result in the operation of an overcurrent•protective device.
17.4 There shall be no emission of flame or molten metal or other manifestation of a fire, or risk of electric shock, when each output circuit of the unit is individually shorted. Accessible. interchangeabletype fuses are to be replaced with a fuse of the size fitting the fuseholder but having the highest available current rating.
18 DielectrIc Voltage-Withstand Test
18.1 A visual signal appliance shall withstand for 1 minute, without breakdown, the application of an essentially sinusoidal AC potential of a frequency within the range of 40 — 70 hertz, or a DC potential, between live parts and the enclosure, between live parts and exposed dead-metal parts, and between live parts of circuits operating at different potentials or frequencies. The test potential is to be (also, sec 18.2).
