UL 497C:2001 pdf download – Protectors for Coaxial Communications Circuits
UL 497C:2001 pdf download – Protectors for Coaxial Communications Circuits.
13 Component Temperature Test
13.1 When tested as described in 13.2— 13,4. the current or overvoltage limiting device shall operate for normal rated current during which the surface of the protector components shall not exceed a 65°C rise above ambient temperature. Normal ambient temperature is 25°C. Two protector samples are to be subjected to this test. One sample per trial is to be tested.
13.2 The location of the thermocouple or heat-measuring device is Illustrated in Figure 12.1. When more than one component is used in the protection circuit, each is to be monitored for temperature The test circuit is the same as shown in Figure 11.1 except the source voltage is to be reduced to rated normal operating voltage. The test cuirent is to be adjusted to the rated value using the limiting resistor shown in Figure 111.
13.3 Upon energization of power, the sample is to be monitored continuously until constant temperatures are obtained, Each test trial is to be conducted a minimum of one hour, The trial is concluded when three separate measurements indicate that there is no change in temperature. Each of the temperature readings is to be measured after a time increment of no less than ten percent of the first time period of one hour or greater,
13.4 The protector, overvoltage and/or overcurrent, shall be classified for use with power limitation (see Installation Instructions, General, Section 35) as defined in the National Electrical Code, ANSI,NFPA 70, for Class 3, non-inherently power sources, and shall be tested in accordance with the limitation shown in Table 13.1.
15 Impulse Sparkover Voltage Measurement Test
15.1 An arrester shall break down at less man iooo volts when subjected separately to single impulse
potentials having both positive and negative polarities. The rate of voltage rise of each impulse is to be
100 ±10 volts per microsecond:
a) From 200 — 1000 volts, inclusive, for the primary protection element: and
b) From 300 — 1500 volts, inclusive, for the back-up or secondary device of the same arrester,
The discharge current shall be sufficient to cause operation in the arc mode but shall not exceed a current
limit of 10 amperes.
152 An arrester intended tot use only as a back-up or secondary device shall break down at less than
16 LImIted Short-Circuit Test
I 6 1 Primary coaxial cable circuit protectors shall withstand the high current conditions of this test without loss of their protective functions or risk of fire and electric shock. Each test trial is to be conducted after conditioning. Different samples are to be subjected to different conditionings and different currents, Sample distribution is shown in Figure 16.1. The conditioning and current combinations are illustrated in Performance. General, Section 10.
16.2 The abnormal high current fault is to be conducted on the center conductor of the coaxial test circuit. The test circuit is connected as illustrated in Figure 16.2. Calibration of the test loads is accomplished by adjusting the voltage and current while the sample has been removed from the circuit,
16.3 The protectors are to be rated for use with a current-limiting device. This information stiall be indicated in accordance with the marking and installation requirements of this standard. During mis test, the protector is to be tested with the current-limiting device specified in the protector’s installation instructions. The location and positioning of both the overvoltage protector and current-limiting device during this test Is illustrated In Figure 16.2.
16.4 In those cases where only a current-limiting device is being evaluated, the circuit is me same as specified In Figure 11.1. During testing, each sample Is to be placed In a position of intended use and all wire connections are to be made using wire gauge sizes large enough to handle the test current wthout ire or abnormal heat to the test fixture. The test ambient is to be 25 ±3°C.